Sensors

 

SENSORS :- Inductive Sensor, Capacitive Sensor, Ultrasonic Sensor, Optical Sensor, Fibre Sensor, Laser Sensor, Conductive Sensor, Magnetic Sensor, Float Sensor, Loop Detectors, Hot Metal Detector (HMD), Light Curtain, Wind Sensors all types of sensors.

SENSORS :-

Inductive Sensor :- An inductive proximity sensor is a type of non-contact electronic proximity sensor that is used to detect the position of metal objects. The sensing range of an inductive switch is dependent on the type of metal being detected.

How does an inductive proximity sensor work?
Inductive Sensor Operating Principles. Inductive proximity sensors are used for non-contact detection of metallic objects. Their operating principle is based on a coil and oscillator that creates an electromagnetic field in the close surroundings of the sensing surface. … Sensitivity when different metals are present.

Inductive Proximity Sensors. Our Inductive Proximity Sensors detect metal objects without touching them. This technology is used in applications where the metal object to be detected is within an inch or two of the sensor face.

How do proximity switches work?
A proximity sensor often emits an electromagnetic field or a beam of electromagnetic radiation (infrared, for instance), and looks for changes in the field or return signal. The object being sensed is often referred to as the proximity sensor’s target. Different proximity sensor targets demand different sensors.

What is a capacitive proximity sensor?
Typical Applications. Capacitive Proximity Sensing. Capacitive sensing is a noncontact technology suitable for detecting metals, nonmetals, solids, and liquids, although it is best suited for nonmetallic targets because of its characteristics and cost relative to inductive proximity sensors.

What is the use of proximity switch?
A proximity switch is a device which causes a switching action without physical contact. SCHMERSAL proximity switches respond to targets that come within the active range of their generated sensing fields.

What is a capacitive sensor?
In electrical engineering, capacitive sensing is a technology, based on capacitive coupling, that takes human body capacitance as input. Capacitive sensors detect anything that is conductive or has a dielectric different from that of air.

What is a photoelectric sensor?
A photoelectric sensor, or photo eye, is an equipment used to discover the distance, absence, or presence of an object by using a light transmitter, often infrared, and a photoelectric receiver. They are largely used in industrial manufacturing.

What is PNP and NPN proximity switch?
Most industrial proximity sensors (inductive, capacitive, ultrasonic and photo electric) are solid state. The term solid state refers to the type of components used within the sensor. Solid state electronic components such as transistors are used to switch the output of the sensor upon detection of an object.

How does a proxy switch work?
A proximity switch works by emitting an electromagnetic field and monitoring it, activating whenever a sensor detects a change in the field. The activation of the sensor then sends an output or an electrical signal to switch on a light, alarm or device.

What are the different types of proximity sensors?
Proximity Sensors Compared: Inductive, Capacitive, Photoelectric, and Ultrasonic. Proximity sensors detect the presence or absence of objects using electromagnetic fields, light, and sound. There are many types, each suited to specific applications and environments.

How does a capacitive sensor works?
Capacitance and Distance. Noncontact capacitive sensors work by measuring changes in an electrical property called capacitance. Capacitance describes how two conductive objects with a space between them respond to a voltage difference applied to them.

What is an inductive proximity switch?
An inductive proximity sensor is a type of non-contact electronic proximity sensor that is used to detect the position of metal objects. The sensing range of an inductive switch is dependent on the type of metal being detected.

What is an ultrasonic proximity sensor?
Ultrasonic proximity sensors emit and receive sound waves. The carrier signal is a high frequency, inaudible sound wave. They detect the presence of the target object in one of two configurations. … When a target enters the sensing range of the device, the ultrasonic waves are reflected back to the sensor.

How does it work capacitive touch screen?
Unlike resistive touch screens, capacitive screens do not use the pressure of your finger to create a change in the flow of electricity. Instead, they work with anything that holds an electrical charge – including human skin

How does the touch sensor work?
Tactile sensors are sensitive to touch, force or pressure, and are made using light (optical), electricity or magnetism. The stimulus-to-response pathways seen in electronic touch sensor operation mimics the human body process that involves our skin, signal transmission via the nervous system, and brain

What is a through beam sensor?
The emitter and receiver are in separate housings and are aimed directly opposite each other or in direct line of sight. When the target breaks the light beam, which can be infrared, visible red or laser, the output is activated. Through-beam sensors offer the longest sensing range of up to 100 meters

How does a photoelectric sensor work?
As with diffused mode sensing, the transmitter and receiver are in the same housing, but a reflector is used to reflect the light from the transmitter back to the receiver. The target is detected when it blocks the beam from the photoelectric sensor to the reflector.

What is the difference between a PNP and NPN sensor?
PNP sensors are sometimes called “sourcing sensors” because they source positive power to the output. NPN sensors are sometime called “sinking sensors” because they sink ground to the output. The term “load” identifies the device the sensor powers.

What is the difference between NPN and PNP?
The outputs of some sensors will behave like transistors, when a sensor senses an object it will trigger the transistor controlling the output (which essentially acts like a switch) and depending on its design it’ll act as an NPN or PNP type transistor. An NPN output is commonly called a “sinking” output.

What is the use of ambient light sensor in mobile phones?
The ambient light sensor adjusts the brightness of your display according to the external environment. Meanwhile, the proximity sensor detects changes in distance between objects and your phone. For example, it allows the screen of your smartphone to timeout during a call because the phone is placed next to your ear.

What is L sensor?
Modern mobile phones come with a variety of sensors that automate or easy many of our daily tasks. This field takes into account the presence of an accelerometer, a gyroscope, a compass, and a barometer. Accelerometer and gyroscope. Accelerometers in mobile phones are used to detect the orientation of the phone.

What are all the sensors in a car?
MAF (mass air flow sensor), MAP (manifold air pressure sensor), Oxygen Sensor, TPS (throttle position sensor), wheel speed sensor, lateral acceleration sensor, engine coolant temperature sensor, ACRS (air cushion restraint system), HVAC (heating ventilation and air conditioning), EGO (exhaust gas oxygen), crankshaft

What are the different types of sensors?
Temperature Sensor.
IR Sensor.
Ultrasonic Sensor.
Touch Sensor.
Proximity Sensors.
Pressure Sensor.
Level Sensors.
Smoke and Gas Sensors.

What is meant by capacitive transducer?
The capacitive transducer comprises of two parallel metal plates that are separated by the material such as air, which is called as the dielectric material. In the typical capacitor the distance between the two plates is fixed, but in variable capacitance transducers the distance between the two plates is variable.

What is a capacitive touch screen?
Capacitive touchscreen displays rely on the electrical properties of the human body to detect when and where on a display the user touches. Because of this, capacitive displays can be controlled with very light touches of a finger and generally cannot be used with a mechanical stylus or a gloved hand.

What is the use of proximity sensor in android?
The proximity sensor on most smart-phones with touchscreen exists to disable accidental touch events. The most common scenario is the ear coming in contact with the screen and generating touch events, while on a call.

What is a Hall effect sensor?
A Hall effect sensor is a transducer that varies its output voltage in response to a magnetic field. Hall effect sensors are used for proximity switching, positioning, speed detection, and current sensing applications. In its simplest form, the sensor operates as an analog transducer, directly returning a voltage.

What is an ultrasonic sensor?
Active ultrasonic sensors generate high-frequency sound waves and evaluate the echo which is received back by the sensor, measuring the time interval between sending the signal and receiving the echo to determine the distance to an object.

What is the use of ultrasonic sensor?
Distance Measurement Sensor Applications. Ultrasonic Sensors measure the distance of target objects or materials through the air using “non-contact” technology. They measure distance without damage and are easy to use and reliable. Whether used indoors or out, sensors can take abuse.

What is the touch sensor?
A touch sensor is a type of equipment that captures and records physical touch or embrace on a device and/or object. It enables a device or object to detech touch, typically by a human user or operator. A touch sensor may also be called a touch detector.

What is a touch switch?
A touch switch is a type of switch that only has to be touched by an object to operate. It is used in many lamps and wall switches that have a metal exterior as well as on public computer terminals. A touchscreen includes an array of touch switches on a display. A touch switch is the simplest kind of tactile sensor.

What is a diffuse photoelectric sensor?
Diffuse sensors operate on the principal that when a light source is shined on a surface the light is scattered or diffused in many directions. A small portion of the light, which can be infrared, red or laser, is reflected back to the sensor receiver.

What is a retro reflective sensor?
Retroreflective sensors are photoelectric sensors. They consist of an emitter and receiver in a single housing. The light produced by the emitter is reflected back to the receiver with a reflector. Whenever this light beam is obstructed, the output signal of the sensor changes state.

What is the photo sensor?
A photosensor is an electronic component that detects the presence of visible light, infrared transmission (IR), and/or ultraviolet (UV) energy. … Photosensors are used in a great variety of electronic devices, circuits, and systems, including: fiber optic systems. optical scanners.

How does optical sensors work?
Optical sensors work by converting light into an electronic signal. The sensor is attached to a measuring instrument and an electrical trigger. When light strikes the sensor, it trips the trigger, so a measurement is taken.

Is NPN sinking or sourcing?
This configuration is called common collector or emitter follower. Now the NPN is sourcing, and the PNP is sinking. So, sourcing or sinking doesn’t really have much to do with the type of transistor, but rather what it’s doing. … If the transistor is connected between the device and ground, it is sinking current.

What does NPN stand for in electronics?
NPN stands for negative, positive, negative. Also known as sinking. PNP stands for positive, negative, positive. Also known as sourcing. NPN or PNP typicaly relates to digital signals.

What is the use of gyroscope sensor in mobile phones?
Accelerometers in mobile phones are used to detect the orientation of the phone. The gyroscope, or gyro for short, adds an additional dimension to the information supplied by the accelerometer by tracking rotation or twist.

What are the sensors used in smartphones?
One of the feature that attracts the mobile phone buyer is the smart work it does. Different types of sensors like accelerometer, ambient light sensor, GPS sensor, compass, proximity sensor, pressure sensor, gyroscope etc are behind these smartphones.

What is compass sensor in Android phones?
Compass functionality in phones and tablets is enabled by something a bit more sophisticated – a sensor called a magnetometer, which is used to measure the strength and direction of magnetic fields. By analyzing Earth’s magnetic field, the sensor allows a phone to determine its orientation pretty accurately.

What is the use of light sensor in mobile phones?
They sense changes in the environment and send them to the CPU—the phone’s heart. Sensors commonly used in handsets include accelerometer, gyroscope, proximity sensor, ambient light sensor, and barometer. Let’s see how they work to make our phone smarter.

How does a car sensor work?
Car proximity sensors do very much what they say on the tin – they sense when your vehicle gets close to an object. … Electromagnetic and ultrasonic sensors are the two most often used sensors for parking, and feature in many other applications, including burglar alarms.

What is a sensor PDF?
phenomena into an electrical signal. Active element of a sensor is called a transducer. When input is a physical quantity and output electrical Sensor. When input is electrical and output a physical quantity ? Actuator.

What is the sensor technology?
A sensor is a device that detects and responds to some type of input from the physical environment. The specific input could be light, heat, motion, moisture, pressure, or any one of a great number of other environmental phenomena.

What is the transducer?
A transducer is an electronic device that converts energy from one form to another. Common examples include microphones, loudspeakers, thermometers, position and pressure sensors, and antenna.

How does a capacitive sensor works?
Capacitance and Distance. Noncontact capacitive sensors work by measuring changes in an electrical property called capacitance. Capacitance describes how two conductive objects with a space between them respond to a voltage difference applied to them.

What is meant by inductive transducer?
Like other inductive transducers, this transducer is also used for converting a linear motion into an electrical signal. The basic construction of an LVDT is explained and shown in the figure below. Construction. LVDT Construction. The device consists of a primary winding (P) and two secondary windings named S1 and S2.

What is a resistive touch screen?
Resistive touchscreen displays are composed of multiple layers that are separated by thin spaces. Pressure applied to the surface of the display by a finger or stylus causes the layers to touch, which completes electrical circuits and tells the device where the user is touching.

What is a capacitive sensor?
In electrical engineering, capacitive sensing (sometimes capacitance sensing) is a technology, based on capacitive coupling, that can detect and measure anything that is conductive or has a dielectric different from air.

What is the meaning of proximity sensor in mobile phones?
Today, mobile phones use IR-based proximity sensors to detect the presence of a human ear. This sensing is done for two purposes: Reduce display power consumption by turning off the LCD backlight and to disable the touch screen to avoid inadvertent touches by the cheek.

What is the use of proximity switch?
A proximity switch is a device which causes a switching action without physical contact. SCHMERSAL proximity switches respond to targets that come within the active range of their generated sensing fields.

How do you test a Hall effect sensor?
To check the sensor output, turn the DVOM to AC Volts. Rotate the wheel or whatever speed you are measuring. Place the meter leads across the sensor and measure the AC voltage output. Typically, if the shaft is rotated at about one turn every 2 seconds the output should be around .7 to 1.0 Volts AC.

How does a sonar sensor work?
The Ultrasonic Sensor sends out a high-frequency sound pulse and then times how long it takes for the echo of the sound to reflect back. The sensor has 2 openings on its front. One opening transmits ultrasonic waves, (like a tiny speaker), the other receives them, (like a tiny microphone).

What is the range of ultrasonic sensor?
Provides precise, non-contact distance measurements within a 2 cm to 3 m range. Ultrasonic measurements work in any lighting condition, making this a good choice to supplement infrared object detectors. Simple pulse in/pulse out communication requires just one I/O pin.

What is an ultrasound transducer?
A device that produces sound waves that bounce off body tissues and make echoes. The transducer also receives the echoes and sends them to a computer that uses them to create a picture called a sonogram. Transducers (probes) come in different shapes and sizes for use in making pictures of different parts of the body.

How does it work capacitive touch screen?
Unlike resistive touch screens, capacitive screens do not use the pressure of your finger to create a change in the flow of electricity. Instead, they work with anything that holds an electrical charge – including human skin

What is a capacitive keyboard?
A capacitive keyboard is a type of computer keyboard that uses a change of capacitance on the capacitor pad to detect a pressed key on a keyboard. It provides functionality similar to a standard contact keyboard, but its internal structure is different and is fairly quicker and more reliable.

How does a photo eye work?
A photoelectric sensor, or photo eye, is an equipment used to discover the distance, absence, or presence of an object by using a light transmitter, often infrared, and a photoelectric receiver. They are largely used in industrial manufacturing.

What is diffuse reflective?
Diffuse reflection is the reflection of light from a surface such that an incident ray is reflected at many angles rather than at just one angle as in the case of specular reflection.

What is a photoelectric transducer?
When light falls on photosensitive element electric current is generated that is measured directly or after amplification. PHOTOELECTRIC EFFECT is the ejection of electrons from a metal or semiconductor surface when illuminated by light or any radiation of suitable wavelength. PASSIVE TRANSDUCERS

How does a photoelectric sensor work?
As with diffused mode sensing, the transmitter and receiver are in the same housing, but a reflector is used to reflect the light from the transmitter back to the receiver. The target is detected when it blocks the beam from the photoelectric sensor to the reflector.

What is a through beam sensor?
The emitter and receiver are in separate housings and are aimed directly opposite each other or in direct line of sight. When the target breaks the light beam, which can be infrared, visible red or laser, the output is activated. Through-beam sensors offer the longest sensing range of up to 100 meters.

What is a diffuse photoelectric sensor?
Diffuse sensors operate on the principal that when a light source is shined on a surface the light is scattered or diffused in many directions. A small portion of the light, which can be infrared, red or laser, is reflected back to the sensor receiver.

What is a fiber optic sensor?
A fiber optic sensor is a sensor that uses optical fiber either as the sensing element (“intrinsic sensors”), or as a means of relaying signals from a remote sensor to the electronics that process the signals (“extrinsic sensors”). Fibers have many uses in remote sensing.

What is optical proximity sensor?
Optical Proximity Sensors. … These sensors are more commonly known as light beam sensors of the thru-beam type or of the retro reflective type. Both sensor types are shown below. A complete optical proximity sensor includes a light source, and a sensor that detects the light.

What is the difference between NPN and PNP?
PNP sensors are sometimes called “sourcing sensors” because they source positive power to the output. NPN sensors are sometime called “sinking sensors” because they sink ground to the output. The term “load” identifies the device the sensor powers. The load could be a lamp, pneumatic valve, relay or PLC input.

What is NPN sensor?
The outputs of some sensors will behave like transistors, when a sensor senses an object it will trigger the transistor controlling the output (which essentially acts like a switch) and depending on its design it’ll act as an NPN or PNP type transistor. An NPN output is commonly called a “sinking” output

What is a gyro sensor?
Gyro sensors, also known as angular rate sensors or angular velocity sensors, are devices that sense angular velocity. Angular velocity. In simple terms, angular velocity is the change in rotational angle per unit of time. Angular velocity is generally expressed in deg/s (degrees per second).

What is a barometer sensor?
Modern mobile phones come with a variety of sensors that automate or easy many of our daily tasks. This field takes into account the presence of an accelerometer, a gyroscope, a compass, and a barometer. Accelerometer and gyroscope. Accelerometers in mobile phones are used to detect the orientation of the phone.

What do you mean by G sensor?
Gravity sensor is an accelerometer. An accelerometer is a device that measures proper acceleration (“g-force”). … For example, an accelerometer at rest on the surface of the Earth will measure an acceleration g= 9.81 m/s2 straight upwards.

How do reverse parking sensors work?
Ultrasonic Sensors. These types emit radio or ultrasonic waves that bounce off of objects behind the vehicle, much like some animals use echolocation. … For example, some surface types can interfere with how sound waves reflect, or, if an object is too narrow or small to reflect sound waves, your sensor will not see it.

What is a proximity detector?
A proximity sensor is a sensor able to detect the presence of nearby objects without any physical contact. A proximity sensor often emits an electromagnetic field or a beam of electromagnetic radiation (infrared, for instance), and looks for changes in the field or return signal.

What is an inductive sensor?
An inductive proximity sensor is a type of non-contact electronic proximity sensor that is used to detect the position of metal objects. The sensing range of an inductive switch is dependent on the type of metal being detected.

What are electronic sensors used for?
A sensor is a device that detects and responds to some type of input from the physical environment. The specific input could be light, heat, motion, moisture, pressure, or any one of a great number of other environmental phenomena.

What is an active transducer?
Solution: A transducer is a device that converts input energy into output energy. Typically the output energy is differing in kind but related to the input. Active transducers generate electric current or voltage directly in response to environmental stimulation.

What is the difference between a sensor and transducer?
Sensors are almost always transducers but transducers are not necessarily sensors. A transducer is a device which converts signals from one form to another. This can include loudspeakers and linear positioners are well as physical quantity to electrical signal devices.

What is a temperature sensor used for?
A temperature sensor is a device, typically, a thermocouple or RTD, that provides for temperature measurement through an electrical signal. A thermocouple (T/C) is made from two dissimilar metals that generate electrical voltage in direct proportion to changes in temperature.

Capacitive Sensor :-

In electrical engineering, capacitive sensing (sometimes capacitance sensing) is a technology, based on capacitive coupling, that can detect and measure anything that is conductive or has a dielectric different from air.

Many types of sensors use capacitive sensing, including sensors to detect and measure proximity, position or displacement, humidity, fluid level, and acceleration. Human interface devices based on capacitive sensing, such as trackpads, can replace the computer mouse. Digital audio players, mobile phones, and tablet computers use capacitive sensing touchscreens as input devices. Capacitive sensors can also replace mechanical buttons.

Ultrasonic Sensor :-

What is an Ultrasonic Sensor?
An Ultrasonic sensor is a device that can measure the distance to an object by using sound waves. It measures distance by sending out a sound wave at a specific frequency and listening for that sound wave to bounce back. By recording the elapsed time between the sound wave being generated and the sound wave bouncing back, it is possible to calculate the distance between the sonar sensor and the object.

Since it is known that sound travels through air at about 344 m/s (1129 ft/s), you can take the time for the sound wave to return and multiply it by 344 meters (or 1129 feet) to find the total round-trip distance of the sound wave. Round-trip means that the sound wave traveled 2 times the distance to the object before it was detected by the sensor; it includes the ‘trip’ from the sonar sensor to the object AND the ‘trip’ from the object to the Ultrasonic sensor (after the sound wave bounced off the object). To find the distance to the object, simply divide the round-trip distance in half.

NOTE: The accuracy of Ultrasonic sensor can be affected by the temperature and humidity of the air it is being used in. However, for these tutorials and almost any project you will be using these sensors in, this change in accuracy will be negligible.

It is important to understand that some objects might not be detected by ultrasonic sensors. This is because some objects are shaped or positioned in such a way that the sound wave bounces off the object, but are deflected away from the Ultrasonic sensor. It is also possible for the object to be too small to reflect enough of the sound wave back to the sensor to be detected. Other objects can absorb the sound wave all together (cloth, carpeting, etc), which means that there is no way for the sensor to detect them accurately. These are important factors to consider when designing and programming a robot using an ultrasonic sensor.

Ultrasonic sensors are based on measuring the properties of sound waves with frequency above the human audible range. They are based on three physical principles: time of flight, the Doppler effect, and the attenuation of sound waves. Ultrasonic sensors are non-intrusive in that they do not require physical contact with their target, and can detect certain clear or shiny targets otherwise obscured to some vision-based sensors. On the other hand, their measurements are very sensitive to temperature and to the angle of the target.

Ultrasonic sensors “are based on the measurement of the properties of acoustic waves with frequencies above the human audible range,” often at roughly 40 kHz 1). They typically operate by generating a high-frequency pulse of sound, and then receiving and evaluating the properties of the echo pulse.

Three different properties of the received echo pulse may be evaluated, for different sensing purposes. They are:

Time of flight (for sensing distance)
Doppler shift (for sensing velocity)
Amplitude attenuation (for sensing distance, directionality, or attenuation coefficient)

The ultrasonic sensor uses this information along with the time difference between sending and receiving the sound pulse to determine the distance to an object.

Ultrasonic transducers are divided into three broad categories: transmitters, receivers and transceivers. Transmitters convert electrical signals into ultrasound, receivers convert ultrasound into electrical signals, and transceivers can both transmit and receive ultrasound.

In a similar way to radar and sonar, ultrasonic transducers are used in systems which evaluate targets by interpreting the reflected signals. For example, by measuring the time between sending a signal and receiving an echo the distance of an object can be calculated. Passive ultrasonic sensors are basically microphones that detect ultrasonic noise that is present under certain conditions.

Ultrasonic probes and ultrasonic baths apply ultrasonic energy to agitate particles in a wide range of materials

Optical Sensor :-
Electro-optical sensor
Electro-optical sensors are electronic detectors that convert light, or a change in light, into an electronic signal. They are used in many industrial and consumer applications, for example:

Lamps that turn on automatically in response to darkness
Position sensors that activate when an object interrupts a light beam
Flash detection, to synchronize one photographic flash to another
Photoelectric sensors that detect the distance, absence, or presence of an object

Types of Optical Sensors and Switches
There are many different kinds of optical sensors, the most common types are:

Photoconductive devices convert a change of incident light into a change of resistance.
Photovoltaics, commonly known as solar cells, convert an amount of incident light into an output voltage.
Photodiodes convert an amount of incident light into an output current.
Phototransistors are a type of bipolar transistor where the base-collector junction is exposed to light. This results in the same behaviour of a photodiode, but with an internal gain.
Optical Switches are usually used in optical fibers, where the electro-optic effect is used to switch one circuit to another. These switches can be implemented with, for example, microelectromechanical systems or piezoelectric systems.

Applications
Electro-optical sensors are used whenever light needs to be converted to energy. Because of this, electro-optical sensors can be seen almost anywhere. Common applications are smartphones where sensors are used to adjust screen brightness, and smartwatches in which sensors are used to measure the wearer’s heartbeat.

Optical sensors can be found in the energy field to monitor structures that generate, produce, distribute, and convert electrical power. The distributed and nonconductive nature of optical fibres makes optical sensors perfect for oil and gas applications, including pipeline monitoring. They can also be found in wind turbine blade monitoring, offshore platform monitoring, power line monitoring and downhole monitoring. Other applications include the civil and transportation fields such as bridge, airport landing strip, dam, railway, airplane, wing, fuel tank and ship hull monitoring.

Among other applications, optical switches can be found in thermal methods which vary the refraction index in one leg of an interferometer in order to switch the signal, MEMS approaches involving arrays of micromirrors that can deflect an optical signal to the appropriate receiver, piezoelectric beam steering liquid crystals which rotate polarized light depending on the applied electric field and acousto-optic methods which change the refraction index as a result of strain induced by an acoustic field to deflect light.

Another important application of optical sensor is to measure the concentration of different compounds by both visible and infrared spectroscopy.

Fibre Sensor :-

A fiber optic sensor is a sensor that uses optical fiber either as the sensing element (“intrinsic sensors”), or as a means of relaying signals from a remote sensor to the electronics that process the signals (“extrinsic sensors”). Fibers have many uses in remote sensing. Depending on the application, fiber may be used because of its small size, or because no electrical power is needed at the remote location, or because many sensors can be multiplexed along the length of a fiber by using light wavelength shift for each sensor, or by sensing the time delay as light passes along the fiber through each sensor. Time delay can be determined using a device such as an optical time-domain reflectometer and wavelength shift can be calculated using an instrument implementing optical frequency domain reflectometry.

Fiber optic sensors are also immune to electromagnetic interference, and do not conduct electricity so they can be used in places where there is high voltage electricity or flammable material such as jet fuel. Fiber optic sensors can be designed to withstand high temperatures as well.

Intrinsic sensors
Optical fibers can be used as sensors to measure strain, temperature, pressure and other quantities by modifying a fiber so that the quantity to be measured modulates the intensity, phase, polarization, wavelength or transit time of light in the fiber.

Extrinsic sensors

Extrinsic fiber optic sensors use an optical fiber cable, normally a multimode one, to transmit modulated light from either a non-fiber optical sensor, or an electronic sensor connected to an optical transmitter.

Diffuse Scan Sensors
These sensors are made of high-grade raw material and components procured from reliable vendors. Our range of photoelectric sensors includes diffuse scan

The Fibre Optical Sensors

1. INTRODUCTION
Recently, fibre optical sensors (FOS) have gained increased popularity and market acceptance. In comparison to conventional sensors they offer a number of distinct advantages which makes them unique for certain types of applications, mainly where conventional sensors are difficult or impossible to deploy or can not provide the same wealth of information.

2. TYPES OF FIBRE OPTICAL SENSORS
According to the spatial distribution of the measurand (the quantity to be measured), FOS can be classified as…

Point sensors: the measurement is carried out at a single point in space, but possibly multiple channels for addressing multiple points.
Examples are Fabry-Perot sensors and single Fibre Bragg Grating (FBG) sensors.

Integrated sensors: the measurement averages a physical parameter over a certain spatial section and provides a single value.
An example is a deformation sensor measuring strain over a long base length.

Quasi-distributed or multiplexed sensors: the measurand is determined at a number of fixed, discrete points along a single fibre optical cable. The most common example are multiplexed FBG’s.

Distributed sensor: the parameter of interest is measured with a certain spatial resolution at any point along a single optical cable.
Examples include systems based on Rayleigh, Raman and Brillouin scattering.

3. GENERAL ADVANTAGES OF FIBRE OPTICAL SENSORS

Completely passive: can be used in explosive environment.

Immune to electromagnetic interference: ideal for microwave environment.

Resistant to high temperatures and chemically reactive environment: ideal for harsh and hostile environment.

Small size: ideal for embedding and surface mounting.

High degree of biocompatibility, non-intrusive nature and electromagnetic immune: ideal for medical applications like intra-aortic balloon pumping.

Can monitor a wide range of physical and chemical parameters.

Potential for very high sensitivity, range and resolution.

Complete electrical insulation from high electrostatic potential.

Remote operation over several km lengths without any lead sensitivity: ideal for deployment in boreholes or measurements in hazardous environment.
Multiplexed and distributed sensors are unique in that they provide measurements at a large number of points along a single optical cable: ideal for minimising cable deployment and cable weight, or for monitoring extended structures like pipelines, dams etc.

In what follows we give a brief explanation of the working principles of optical fibres and each type of sensors.

4. OPTICAL FIBRES
An optical fibre consists of a thin, low-loss glass wire with a centre or core region having a slightly higher refractive index than its surrounding region or cladding.

A fiber optic sensor is a sensor that uses optical fiber either as the sensing element (“intrinsic sensors”), or as a means of relaying signals from a remote sensor to the electronics that process the signals (“extrinsic sensors”). Fibers have many uses in remote sensing.

How does optical sensors work?
Optical sensors work by converting light into an electronic signal. The sensor is attached to a measuring instrument and an electrical trigger. When light strikes the sensor, it trips the trigger, so a measurement is taken.

What is a fiber optic?
A technology that uses glass (or plastic) threads (fibers) to transmit data. A fiber optic cable consists of a bundle of glass threads, each of which is capable of transmitting messages modulated onto light waves.

What is an optical sensor?
An optical sensor is generally part of a larger system that integrates a source of light, a measuring device and the optical sensor. This is often connected to an electrical trigger. The trigger reacts to a change in the signal within the light sensor.

What is an optical detector?
Detectors perform the opposite function of light emitters. They convert optical signals back into electrical impulses that are used by the receiving end of the fiber optic data, video, or audio link. The most common detector is the semiconductor photodiode, which produces current in response to incident light.

 

What is optical proximity sensor?
Optical Proximity Sensors These sensors are more commonly known as light beam sensors of the thru-beam type or of the retro reflective type. Both sensor types are shown below. A complete optical proximity sensor includes a light source, and a sensor that detects the light.

 

How do heart rate monitor work?
Optical heart rate sensors use a methodology called photoplethysmography (PPG) to measure heart rate. PPG is a technical term for shining light into the skin and measuring the amount of light that is scattered by blood flow.

What is a heart rate sensor?
A comfortable heart rate sensor strap which you connect via bluetooth to your fitness app or training device. Monitor your real-time, accurate heart rate while you train, review and analyze it during or after workouts.

What is an optical switch?
In telecommunication, an optical switch is a switch that enables signals in optical fibers or integrated optical circuits (IOCs) to be selectively switched from one circuit to another.

How does a fiber optic cable work?
Imagine what they’d make of modern fiber-optic cables—”pipes” that can carry telephone calls and emails right around the world in a seventh of a second! Photo: Light pipe: fiber optics means sending light beams down thin strands of plastic or glass by making them bounce repeatedly off the walls

What is a sensor in electronics?
A sensor is a device that detects and responds to some type of input from the physical environment. The specific input could be light, heat, motion, moisture, pressure, or any one of a great number of other environmental phenomena.

Laser Sensor : –
Laser Sensors
Laser sensors can detect, count, trigger, map, profile, scan, and guide as well as verify levels, proximities and distances to practically anything you can think of. LTI’s laser sensors are ideal for many specific applications in Plant Management and Automation, Security and Surveillance, Vehicle Guidance and Automation and Traffic Management.

Laser sensors for collision avoidance
The variation in material characteristics or the difference in environmental conditions is typically the contributing factor of why a certain measurement technology won’t work. Some equipment and methods struggle to recognize a moving target in dusty conditions whereas others have difficulties obtaining a valid level measurement to liquids.

Considering all these factors and more, it would be nearly impossible to design an all-encompassing laser sensor that could work in a wide variety of scenarios. This is why Laser Technology has engineered a unique line of laser sensors with specific characteristics and capabilities that can overcome particular challenges.

All laser sensors are non-contact (a.ka. reflectorless), allowing you to measure a distance to a target or material without the need of reflective material. The other key to non-contact measurements is that the laser sensor can be aligned to the target from practically any distance or angle within its range. Sensors will also return an accurate measurement to more difficult targets, including most liquids and solids.

Laser sensors measuring bin levels
Some key benefits to infrared laser sensors are: fast data rates, small beam footprint, and ability to penetrate air-borne particulates, scanning capabilities, multiple target detection, and measurements to most surfaces and targets that are independent of incident angle.

All laser sensors are eye safe and highly configurable allowing the user to optimize and customize the measurement performance to meet demanding conditions easily, safely, reliably and inexpensively. Where other measurement alternatives fall short, non-contact, pulse-laser technology rises to the challenge.

How laser sensors measure up:

Easily identifies difficult targets such as liquids, non-reflective material and fast moving objects.
Makes non-contact and non-intrusive measurements without the need for frequent calibration.
Recognizes small targets at long distances, within narrow openings and from sharp angles.
Performs under temperature variations, background noise, vapor pressure and low dielectric or acoustically absorbing materials.

 

Conductive Sensor : –
In electrical engineering, capacitive sensing (sometimes capacitance sensing) is a technology, based on capacitive coupling, that can detect and measure anything that is conductive or has a dielectric different from air. In general, the measurement of conductivity is a rapid and inexpensive way of determining the ionic strength of a solution. Conductivity is used to measure the purity of water or the concentration of ionized chemicals in water. Conductivity sensors measure the ability of a solution to conduct an electrical current. It is the presence of ions in a solution that allow the solution to be conductive: the greater the concentration of ions, the greater the conductivity.

In electrical engineering, capacitive sensing (sometimes capacitance sensing) is a technology, based on capacitive coupling, that can detect and measure anything that is conductive or has a dielectric different from air.

Many types of sensors use capacitive sensing, including sensors to detect and measure proximity, position or displacement, humidity, fluid level, and acceleration. Human interface devices based on capacitive sensing, such as trackpads, can replace the computer mouse. Digital audio players, mobile phones, and tablet computers use capacitive sensing touchscreens as input devices. Capacitive sensors can also replace mechanical buttons.

 

Magnetic Sensor :-

MAGNETIC SENSORS
Magnetic sensors detect changes and disturbances in a magnetic field like flux, strength and direction. Other types of detection sensors work with characteristics like temperature, pressure, light. From established knowledge about the existing magnetic field and the data collected from sensors regarding changes and alterations, many things can be known. Rotation, angles, direction, presence and electrical current can all be monitored. Magnetic sensors are divided into two groups, those that measure the complete magnetic field and those that measure vector components of the field. The vector components are the individual points of the magnetic field. The techniques used to create these sensors involve various combinations of physics and electronics.

MEASURING A MAGNETIC FIELD
A magnetic field surrounds an electric current. The field is detectable by its force or interaction on electrical charges, magnets and magnetic products. The strength and direction of a magnetic field can be measured and documented. Fluctuations in that field are sensed and adjustments or changes are made in a machines response, a doctors decisions, the direction the navigational instrument gives or the response of a detection system. The Earth’s magnetic field is a great example. It is measured and tracked by magnetic sensors which are part of the navigational tools that Honeywell and other corporations design and manufacture. Most magnetic sensors are used for measurement in industrial processes, navigational tools, and scientific measuring.

MAGNETIC SENSING TECHNOLOGY
There are several types of technologies used to make a magnetic sensor work. Fluxgate, Hall Effect, magnetoresisitive, magnetoinductive, proton precession, optical pump, , nuclear precession, and SQUID (superconducting quantum interference devices) each have a different approach to using magnetic sensors. Magnetoresistive devices record electrical resistance of the magnetic field. Magnetoinductive are coils surrounding magnetic material whose ability to be permeated changes within the Earth’s magnetic field. Fluxgate measures magnetic fields against a known internally created magnetic based response that runs through a continually fluxing set of parameters. Each type of technology focuses on a particular area for detection, a measurement to be detected and way of recording changes.

THE SMALLEST MAGNETIC SENSOR
A recent discovery may allow improvements to magnetic sensors across the board. The NIST (National Institute of Standards And Technology) have revealed that combining layers of magnetic alloy with nano layers of silver increase magnetic sensitivity. Being able to use an extremely thin magnetic sensor (called thin films) is a necessity in applications found in medical devices, weapon detection and data storage.

Float Sensor :-
A float switch is a device used to detect the level of liquid within a tank. The switch may be used in a pump, an indicator, an alarm, or other devices.

How does a float sensor work?
The purpose of a float switch is to open or close a circuit as the level of a liquid rises or falls. Most float switches are “normally closed,” meaning the two wires coming from the top of the switch complete a circuit when the float is at its low point, resting on its bottom clip (for example, when a tank is dry).

What is a liquid level sensor?
Level sensors detect the level of liquids and other fluids and fluidized solids, including slurries, granular materials, and powders that exhibit an upper free surface.

What is a float switch in an air conditioner?
The fix for an overflow that the drain pan cannot handle is a safety float switch. If the moisture begins to collect in the drainage line, a small ball valve, within the safety switch, will begin to float thus transmitting a signal to the compressor unit to turn off.

What is the use of pressure switch?
A pressure switch is a form of switch that closes an electrical contact when a certain set pressure has been reached on its input. The switch may be designed to make contact either on pressure rise or on pressure fall.

What is the level switch?
A float switch is a device used to detect the level of liquid within a tank. The switch may be used in a pump, an indicator, an alarm, or other devices.

What is the level measurement?
Level measurement devices can detect, indicate, and/or help control liquid or solid levels. Level measurement devices can be separated into two categories: direct, or mechanical, measurement and electronic measurement.

What is the use of level transmitter?
A Level Transmitter is simply an instrument that provides continuous level measurement. Level transmitters can be used to determine the level of a given liquid or bulk-solid at any given time.

How does an automobile coolant level sensor work?
While manufacturers use different types of coolant-level sensors, the simplest is a float that activates a switch. If the coolant drops below the designated level, the switch opens, sending a signal to the indicator light. Manufacturers install these switches either in the coolant recovery tank or in the radiator.

What is ultrasonic level transmitter?
Sonic is the sound we can hear. Ultrasonic is the sound above human hearing range. Human can hear maximum up to a frequency of 20 KHz. Ultrasonic frequencies are above 20 KHz. Ultrasonic waves are used to measure level of liquids and solid objects in industries.

What is the principle of capacitance type level transmitter?
Capacitance level instruments operate on the basic principle of the variation of the electrical capacity of a capacitor formed by the sensor, the vessel wall and the dielectric material. A capacitor is made of two conductive plates which are isolated from each other by a dielectric.

What is the use of differential pressure switch?
The Differential Pressure Switch just like the pressure switch is a simple electro- mechanical device that operates on the basic principles of Levers and opposing forces. They are mainly used for sensing a difference in pressure between two points in a plant or system.

What is the function of the limit switch?
The limit switch then regulates the electrical circuit that controls the machine and its moving parts. These switches can be used as pilot devices for magnetic starter control circuits, allowing them to start, stop, slow down, or accelerate the functions of an electric motor.

Float switch

A float switch is a device used to detect the level of liquid within a tank. The switch may be used in a pump, an indicator, an alarm, or other devices.

Float switches range from small to large and may be as simple as a mercury switch inside a hinged float or as complex as a series of optical or conductance sensors producing discrete outputs as the liquid reaches many different levels within the tank. Perhaps the most common type of float switch is simply a float raising a rod that actuates a microswitch.

Tilt Sensors

Microelectromechanical systems

A MEMS-based magnetic field sensor is a small-scale microelectromechanical (MEMS) device for detecting and measuring magnetic fields. Many of these operate by detecting effects of the Lorentz force: a change in voltage or resonant frequency may be measured electronically, or a mechanical displacement may be measured optically. Compensation for temperature effects is necessary. Such instruments have medical and biomedical applications.

How does a pressure transmitter works?
A pressure transducer, often called a pressure transmitter, is a transducer that converts pressure into an analog electrical signal. Although there are various types of pressure transducers, one of the most common is the strain-gage base transducer.

How does an ultrasonic distance sensor work?
The Ultrasonic Sensor sends out a high-frequency sound pulse and then times how long it takes for the echo of the sound to reflect back. The sensor has 2 openings on its front. One opening transmits ultrasonic waves, (like a tiny speaker), the other receives them, (like a tiny microphone).

Loop Detectors :-

Induction loop

An induction or inductive loop is an electromagnetic communication or detection system which uses a moving magnet to induce an electric current in a nearby wire. Induction loops are used for transmission and reception of communication signals, or for detection of metal objects in metal detectors or vehicle presence indicators. A common modern use for induction loops is to provide hearing assistance to hearing-aid users.

Vehicle detection loops, called inductive-loop traffic detectors, can detect vehicles passing or arriving at a certain point, for instance approaching a traffic light or in motorway traffic. An insulated, electrically conducting loop is installed in the pavement.

How does an induction loop system work?
An induction loop system transmits an audio signal directly into a hearing aid via a magnetic field, greatly reducing background noise, competing sounds, reverberation and other acoustic distortions that reduce clarity of sound.

How does a stop light work?
These detectors are buried in or under the roadway. Inductive detector loops are the most common type. They are sensors buried in the road to detect the presence of traffic waiting at the light, and thus can reduce the time when a green signal is given to an empty road.

How does a hearing loop system work?
A hearing loop (sometimes called an audio induction loop) is a special type of sound system for use by people with hearing aids. The hearing loop provides a magnetic, wireless signal that is picked up by the hearing aid when it is set to ‘T’ (Telecoil) setting.

What is a sound loop?
Audio induction loop. … Audio induction loop systems, also called audio-frequency induction loops (AFILs) or hearing loops, are an assistive listening technology for individuals with reduced ranges of hearing.

Hot Metal Detector (HMD) :-

Series of optical sensor are designed to detect the presence of hot infrared emitting bodies. Typical applications are the material presence detection in hot wire rod, bar and section mills or in plate and hot strip mills, but they can be applied in any situation where hot objects should be detected. Series of sensors have been designed specifically for the steel industry and are capable of being directly installed in harsh environmental conditions. Several solutions are available in terms of mechanical arrangements (e.g. fiberoptic sensing head options), temperature ranges and field of view geometries.

Hot Metal Detectors (HMD) are used in many different applications throughout the metals rolling process, for target detection, tracking and length determination. They are also an essential component of cut-to-length systems.

ROLLING MILLS
To Control cut to length shearing, monitor hot rods, controlling roller tables, coil regulating, switching in crosscut hauler, monitor de-scaler, cooling beds, winder control, monitor edge washing, continuous casting or tracking of high speed wire.
Detection of Hot Metal or Hot Product in a Rod Mill, Bar Mall, Rolling Mill, Plate Mill, Roughing Mill, Reversing Mill, Hot Strip Mill or other Steel Mill and Industrial Applications.

 

Light Curtain :-
Safety Light curtains are opto-electronic devices that are used to safeguard personnel in the vicinity of moving machinery with the potential to cause harm such as presses, winders and palletisers. Safety Light curtains can be used as an alternative to mechanical barriers and other forms of traditional machine guarding. By reducing the need for physical guards and barriers, safety light curtains can increase the maintainability of the equipment they are guarding. The operability and efficiency of machinery can also be improved by the use of safety light curtains by, for example, allowing easier access for semi-automatic procedures.

Safety Light curtains fall into a category of equipment known as presence detection devices. Other common presence detection devices are pressure-sensitive safety mats and laser scanners (often used on Remotely Operated Vehicles (ROV) when in industrial settings). Most important application of safety relays is in automation industries dealing with robotic cell set up.

Safety Light curtains are supplied as a pair with a transmitter and receiver. The transmitter projects an array of parallel infrared light beams to the receiver which consists of a number of photoelectric cells. When an object breaks one or more of the beams a stop signal is sent to the guarded equipment.

The light beams emitted from the transmitter are sequenced, one after the other, and pulsed at a specific frequency. The receiver is designed to only accept the specific pulse and frequency from its dedicated transmitter. This enables the rejection of spurious infrared light and thus enhances their suitability as components within a safety system.

Typically, safety light curtains are connected to a safety relay which will remove motive power from the hazard in the event that an object is detected. Safety relays can be provided with muting functionality which enables the temporary disabling of the safety function to allow objects to pass through the safety light curtains without tripping the safety relay. This is particularly useful for machinery which has some semi-automatic procedures.

Flexible, cost-saving installation and maintenance with the highest safety
Safety light curtains reliably and cost-effectively protect against access into hazardous points and areas. Depending on the variant, different machine functions are integrated or can be selected via safe control solutions. The range from small and compact types to extremely robust and resistant variants that withstand special ambient conditions up to the highest safety level

Wind Sensors :-

Wind is measured using a so called anemometer. The term is derived from the Greek word anemos, meaning wind. For the measurement of wind speed and wind direction several principles may be used. At this moment wind sensors or anemometers can be divided into two types. Static ones based upon the ultrasonic principle and mechanical cup and vane types sensors. Observator offers a wide range of wind sensors with these two principles, which all have one thing in common: designed to be used within the hardest environmental conditions.

The Wind Sensor is a thermal anemometer based on a traditional technique for measuring wind speed. The technique is called the “hot-wire” technique, and involves heating an element to a constant temperature and then measuring the electrical power that is required to maintain the heated element at temperature as the wind changes. This measured electrical input is then directly proportional to the square of the wind speed.

Principle that makes the sensor function is the same as the traditional hot-wire technique. This technique excels at low to medium wind speed, and is the preferred technique for sensing indoor air movement, where the spinning cup anemometers typically seen on weather stations are ineffective. As an experimenters tool, the sensor is exquisitely sensitive, with a small puff of air being sensed at a distance of 18-24?. Possible applications include human breath detection, room occupancy detection, hvac system monitoring, weather stations and many more.

Wind Turbine Sensors
Wind Speed Sensors

Speed sensor

Speed sensors are machines used to detect the speed of an object, usually a transport vehicle. They include:

Wheel speed sensors
Speedometers
Pitometer logs
Pitot tubes
Airspeed indicators
Piezo sensors (e.g. in a road surface)
LIDAR
Ground speed radar
Doppler radar
ANPR (where vehicles are timed over a fixed distance)
Laser surface velocimeters for moving surfaces

 

all types of sensors etc.

Category: .

Description

SENSORS :- Inductive Sensor, Capacitive Sensor, Ultrasonic Sensor, Optical Sensor, Fibre Sensor, Laser Sensor, Conductive Sensor, Magnetic Sensor, Float Sensor, Loop Detectors, Hot Metal Detector (HMD), Light Curtain, Wind Sensors all types of sensors.

SENSORS :-

Inductive Sensor :- An inductive proximity sensor is a type of non-contact electronic proximity sensor that is used to detect the position of metal objects. The sensing range of an inductive switch is dependent on the type of metal being detected.

How does an inductive proximity sensor work?
Inductive Sensor Operating Principles. Inductive proximity sensors are used for non-contact detection of metallic objects. Their operating principle is based on a coil and oscillator that creates an electromagnetic field in the close surroundings of the sensing surface. … Sensitivity when different metals are present.

Inductive Proximity Sensors. Our Inductive Proximity Sensors detect metal objects without touching them. This technology is used in applications where the metal object to be detected is within an inch or two of the sensor face.

How do proximity switches work?
A proximity sensor often emits an electromagnetic field or a beam of electromagnetic radiation (infrared, for instance), and looks for changes in the field or return signal. The object being sensed is often referred to as the proximity sensor’s target. Different proximity sensor targets demand different sensors.

What is a capacitive proximity sensor?
Typical Applications. Capacitive Proximity Sensing. Capacitive sensing is a noncontact technology suitable for detecting metals, nonmetals, solids, and liquids, although it is best suited for nonmetallic targets because of its characteristics and cost relative to inductive proximity sensors.

What is the use of proximity switch?
A proximity switch is a device which causes a switching action without physical contact. SCHMERSAL proximity switches respond to targets that come within the active range of their generated sensing fields.

What is a capacitive sensor?
In electrical engineering, capacitive sensing is a technology, based on capacitive coupling, that takes human body capacitance as input. Capacitive sensors detect anything that is conductive or has a dielectric different from that of air.

What is a photoelectric sensor?
A photoelectric sensor, or photo eye, is an equipment used to discover the distance, absence, or presence of an object by using a light transmitter, often infrared, and a photoelectric receiver. They are largely used in industrial manufacturing.

What is PNP and NPN proximity switch?
Most industrial proximity sensors (inductive, capacitive, ultrasonic and photo electric) are solid state. The term solid state refers to the type of components used within the sensor. Solid state electronic components such as transistors are used to switch the output of the sensor upon detection of an object.

How does a proxy switch work?
A proximity switch works by emitting an electromagnetic field and monitoring it, activating whenever a sensor detects a change in the field. The activation of the sensor then sends an output or an electrical signal to switch on a light, alarm or device.

What are the different types of proximity sensors?
Proximity Sensors Compared: Inductive, Capacitive, Photoelectric, and Ultrasonic. Proximity sensors detect the presence or absence of objects using electromagnetic fields, light, and sound. There are many types, each suited to specific applications and environments.

How does a capacitive sensor works?
Capacitance and Distance. Noncontact capacitive sensors work by measuring changes in an electrical property called capacitance. Capacitance describes how two conductive objects with a space between them respond to a voltage difference applied to them.

What is an inductive proximity switch?
An inductive proximity sensor is a type of non-contact electronic proximity sensor that is used to detect the position of metal objects. The sensing range of an inductive switch is dependent on the type of metal being detected.

What is an ultrasonic proximity sensor?
Ultrasonic proximity sensors emit and receive sound waves. The carrier signal is a high frequency, inaudible sound wave. They detect the presence of the target object in one of two configurations. … When a target enters the sensing range of the device, the ultrasonic waves are reflected back to the sensor.

How does it work capacitive touch screen?
Unlike resistive touch screens, capacitive screens do not use the pressure of your finger to create a change in the flow of electricity. Instead, they work with anything that holds an electrical charge – including human skin

How does the touch sensor work?
Tactile sensors are sensitive to touch, force or pressure, and are made using light (optical), electricity or magnetism. The stimulus-to-response pathways seen in electronic touch sensor operation mimics the human body process that involves our skin, signal transmission via the nervous system, and brain

What is a through beam sensor?
The emitter and receiver are in separate housings and are aimed directly opposite each other or in direct line of sight. When the target breaks the light beam, which can be infrared, visible red or laser, the output is activated. Through-beam sensors offer the longest sensing range of up to 100 meters

How does a photoelectric sensor work?
As with diffused mode sensing, the transmitter and receiver are in the same housing, but a reflector is used to reflect the light from the transmitter back to the receiver. The target is detected when it blocks the beam from the photoelectric sensor to the reflector.

What is the difference between a PNP and NPN sensor?
PNP sensors are sometimes called “sourcing sensors” because they source positive power to the output. NPN sensors are sometime called “sinking sensors” because they sink ground to the output. The term “load” identifies the device the sensor powers.

What is the difference between NPN and PNP?
The outputs of some sensors will behave like transistors, when a sensor senses an object it will trigger the transistor controlling the output (which essentially acts like a switch) and depending on its design it’ll act as an NPN or PNP type transistor. An NPN output is commonly called a “sinking” output.

What is the use of ambient light sensor in mobile phones?
The ambient light sensor adjusts the brightness of your display according to the external environment. Meanwhile, the proximity sensor detects changes in distance between objects and your phone. For example, it allows the screen of your smartphone to timeout during a call because the phone is placed next to your ear.

What is L sensor?
Modern mobile phones come with a variety of sensors that automate or easy many of our daily tasks. This field takes into account the presence of an accelerometer, a gyroscope, a compass, and a barometer. Accelerometer and gyroscope. Accelerometers in mobile phones are used to detect the orientation of the phone.

What are all the sensors in a car?
MAF (mass air flow sensor), MAP (manifold air pressure sensor), Oxygen Sensor, TPS (throttle position sensor), wheel speed sensor, lateral acceleration sensor, engine coolant temperature sensor, ACRS (air cushion restraint system), HVAC (heating ventilation and air conditioning), EGO (exhaust gas oxygen), crankshaft

What are the different types of sensors?
Temperature Sensor.
IR Sensor.
Ultrasonic Sensor.
Touch Sensor.
Proximity Sensors.
Pressure Sensor.
Level Sensors.
Smoke and Gas Sensors.

What is meant by capacitive transducer?
The capacitive transducer comprises of two parallel metal plates that are separated by the material such as air, which is called as the dielectric material. In the typical capacitor the distance between the two plates is fixed, but in variable capacitance transducers the distance between the two plates is variable.

What is a capacitive touch screen?
Capacitive touchscreen displays rely on the electrical properties of the human body to detect when and where on a display the user touches. Because of this, capacitive displays can be controlled with very light touches of a finger and generally cannot be used with a mechanical stylus or a gloved hand.

What is the use of proximity sensor in android?
The proximity sensor on most smart-phones with touchscreen exists to disable accidental touch events. The most common scenario is the ear coming in contact with the screen and generating touch events, while on a call.

What is a Hall effect sensor?
A Hall effect sensor is a transducer that varies its output voltage in response to a magnetic field. Hall effect sensors are used for proximity switching, positioning, speed detection, and current sensing applications. In its simplest form, the sensor operates as an analog transducer, directly returning a voltage.

What is an ultrasonic sensor?
Active ultrasonic sensors generate high-frequency sound waves and evaluate the echo which is received back by the sensor, measuring the time interval between sending the signal and receiving the echo to determine the distance to an object.

What is the use of ultrasonic sensor?
Distance Measurement Sensor Applications. Ultrasonic Sensors measure the distance of target objects or materials through the air using “non-contact” technology. They measure distance without damage and are easy to use and reliable. Whether used indoors or out, sensors can take abuse.

What is the touch sensor?
A touch sensor is a type of equipment that captures and records physical touch or embrace on a device and/or object. It enables a device or object to detech touch, typically by a human user or operator. A touch sensor may also be called a touch detector.

What is a touch switch?
A touch switch is a type of switch that only has to be touched by an object to operate. It is used in many lamps and wall switches that have a metal exterior as well as on public computer terminals. A touchscreen includes an array of touch switches on a display. A touch switch is the simplest kind of tactile sensor.

What is a diffuse photoelectric sensor?
Diffuse sensors operate on the principal that when a light source is shined on a surface the light is scattered or diffused in many directions. A small portion of the light, which can be infrared, red or laser, is reflected back to the sensor receiver.

What is a retro reflective sensor?
Retroreflective sensors are photoelectric sensors. They consist of an emitter and receiver in a single housing. The light produced by the emitter is reflected back to the receiver with a reflector. Whenever this light beam is obstructed, the output signal of the sensor changes state.

What is the photo sensor?
A photosensor is an electronic component that detects the presence of visible light, infrared transmission (IR), and/or ultraviolet (UV) energy. … Photosensors are used in a great variety of electronic devices, circuits, and systems, including: fiber optic systems. optical scanners.

How does optical sensors work?
Optical sensors work by converting light into an electronic signal. The sensor is attached to a measuring instrument and an electrical trigger. When light strikes the sensor, it trips the trigger, so a measurement is taken.

Is NPN sinking or sourcing?
This configuration is called common collector or emitter follower. Now the NPN is sourcing, and the PNP is sinking. So, sourcing or sinking doesn’t really have much to do with the type of transistor, but rather what it’s doing. … If the transistor is connected between the device and ground, it is sinking current.

What does NPN stand for in electronics?
NPN stands for negative, positive, negative. Also known as sinking. PNP stands for positive, negative, positive. Also known as sourcing. NPN or PNP typicaly relates to digital signals.

What is the use of gyroscope sensor in mobile phones?
Accelerometers in mobile phones are used to detect the orientation of the phone. The gyroscope, or gyro for short, adds an additional dimension to the information supplied by the accelerometer by tracking rotation or twist.

What are the sensors used in smartphones?
One of the feature that attracts the mobile phone buyer is the smart work it does. Different types of sensors like accelerometer, ambient light sensor, GPS sensor, compass, proximity sensor, pressure sensor, gyroscope etc are behind these smartphones.

What is compass sensor in Android phones?
Compass functionality in phones and tablets is enabled by something a bit more sophisticated – a sensor called a magnetometer, which is used to measure the strength and direction of magnetic fields. By analyzing Earth’s magnetic field, the sensor allows a phone to determine its orientation pretty accurately.

What is the use of light sensor in mobile phones?
They sense changes in the environment and send them to the CPU—the phone’s heart. Sensors commonly used in handsets include accelerometer, gyroscope, proximity sensor, ambient light sensor, and barometer. Let’s see how they work to make our phone smarter.

How does a car sensor work?
Car proximity sensors do very much what they say on the tin – they sense when your vehicle gets close to an object. … Electromagnetic and ultrasonic sensors are the two most often used sensors for parking, and feature in many other applications, including burglar alarms.

What is a sensor PDF?
phenomena into an electrical signal. Active element of a sensor is called a transducer. When input is a physical quantity and output electrical Sensor. When input is electrical and output a physical quantity ? Actuator.

What is the sensor technology?
A sensor is a device that detects and responds to some type of input from the physical environment. The specific input could be light, heat, motion, moisture, pressure, or any one of a great number of other environmental phenomena.

What is the transducer?
A transducer is an electronic device that converts energy from one form to another. Common examples include microphones, loudspeakers, thermometers, position and pressure sensors, and antenna.

How does a capacitive sensor works?
Capacitance and Distance. Noncontact capacitive sensors work by measuring changes in an electrical property called capacitance. Capacitance describes how two conductive objects with a space between them respond to a voltage difference applied to them.

What is meant by inductive transducer?
Like other inductive transducers, this transducer is also used for converting a linear motion into an electrical signal. The basic construction of an LVDT is explained and shown in the figure below. Construction. LVDT Construction. The device consists of a primary winding (P) and two secondary windings named S1 and S2.

What is a resistive touch screen?
Resistive touchscreen displays are composed of multiple layers that are separated by thin spaces. Pressure applied to the surface of the display by a finger or stylus causes the layers to touch, which completes electrical circuits and tells the device where the user is touching.

What is a capacitive sensor?
In electrical engineering, capacitive sensing (sometimes capacitance sensing) is a technology, based on capacitive coupling, that can detect and measure anything that is conductive or has a dielectric different from air.

What is the meaning of proximity sensor in mobile phones?
Today, mobile phones use IR-based proximity sensors to detect the presence of a human ear. This sensing is done for two purposes: Reduce display power consumption by turning off the LCD backlight and to disable the touch screen to avoid inadvertent touches by the cheek.

What is the use of proximity switch?
A proximity switch is a device which causes a switching action without physical contact. SCHMERSAL proximity switches respond to targets that come within the active range of their generated sensing fields.

How do you test a Hall effect sensor?
To check the sensor output, turn the DVOM to AC Volts. Rotate the wheel or whatever speed you are measuring. Place the meter leads across the sensor and measure the AC voltage output. Typically, if the shaft is rotated at about one turn every 2 seconds the output should be around .7 to 1.0 Volts AC.

How does a sonar sensor work?
The Ultrasonic Sensor sends out a high-frequency sound pulse and then times how long it takes for the echo of the sound to reflect back. The sensor has 2 openings on its front. One opening transmits ultrasonic waves, (like a tiny speaker), the other receives them, (like a tiny microphone).

What is the range of ultrasonic sensor?
Provides precise, non-contact distance measurements within a 2 cm to 3 m range. Ultrasonic measurements work in any lighting condition, making this a good choice to supplement infrared object detectors. Simple pulse in/pulse out communication requires just one I/O pin.

What is an ultrasound transducer?
A device that produces sound waves that bounce off body tissues and make echoes. The transducer also receives the echoes and sends them to a computer that uses them to create a picture called a sonogram. Transducers (probes) come in different shapes and sizes for use in making pictures of different parts of the body.

How does it work capacitive touch screen?
Unlike resistive touch screens, capacitive screens do not use the pressure of your finger to create a change in the flow of electricity. Instead, they work with anything that holds an electrical charge – including human skin

What is a capacitive keyboard?
A capacitive keyboard is a type of computer keyboard that uses a change of capacitance on the capacitor pad to detect a pressed key on a keyboard. It provides functionality similar to a standard contact keyboard, but its internal structure is different and is fairly quicker and more reliable.

How does a photo eye work?
A photoelectric sensor, or photo eye, is an equipment used to discover the distance, absence, or presence of an object by using a light transmitter, often infrared, and a photoelectric receiver. They are largely used in industrial manufacturing.

What is diffuse reflective?
Diffuse reflection is the reflection of light from a surface such that an incident ray is reflected at many angles rather than at just one angle as in the case of specular reflection.

What is a photoelectric transducer?
When light falls on photosensitive element electric current is generated that is measured directly or after amplification. PHOTOELECTRIC EFFECT is the ejection of electrons from a metal or semiconductor surface when illuminated by light or any radiation of suitable wavelength. PASSIVE TRANSDUCERS

How does a photoelectric sensor work?
As with diffused mode sensing, the transmitter and receiver are in the same housing, but a reflector is used to reflect the light from the transmitter back to the receiver. The target is detected when it blocks the beam from the photoelectric sensor to the reflector.

What is a through beam sensor?
The emitter and receiver are in separate housings and are aimed directly opposite each other or in direct line of sight. When the target breaks the light beam, which can be infrared, visible red or laser, the output is activated. Through-beam sensors offer the longest sensing range of up to 100 meters.

What is a diffuse photoelectric sensor?
Diffuse sensors operate on the principal that when a light source is shined on a surface the light is scattered or diffused in many directions. A small portion of the light, which can be infrared, red or laser, is reflected back to the sensor receiver.

What is a fiber optic sensor?
A fiber optic sensor is a sensor that uses optical fiber either as the sensing element (“intrinsic sensors”), or as a means of relaying signals from a remote sensor to the electronics that process the signals (“extrinsic sensors”). Fibers have many uses in remote sensing.

What is optical proximity sensor?
Optical Proximity Sensors. … These sensors are more commonly known as light beam sensors of the thru-beam type or of the retro reflective type. Both sensor types are shown below. A complete optical proximity sensor includes a light source, and a sensor that detects the light.

What is the difference between NPN and PNP?
PNP sensors are sometimes called “sourcing sensors” because they source positive power to the output. NPN sensors are sometime called “sinking sensors” because they sink ground to the output. The term “load” identifies the device the sensor powers. The load could be a lamp, pneumatic valve, relay or PLC input.

What is NPN sensor?
The outputs of some sensors will behave like transistors, when a sensor senses an object it will trigger the transistor controlling the output (which essentially acts like a switch) and depending on its design it’ll act as an NPN or PNP type transistor. An NPN output is commonly called a “sinking” output

What is a gyro sensor?
Gyro sensors, also known as angular rate sensors or angular velocity sensors, are devices that sense angular velocity. Angular velocity. In simple terms, angular velocity is the change in rotational angle per unit of time. Angular velocity is generally expressed in deg/s (degrees per second).

What is a barometer sensor?
Modern mobile phones come with a variety of sensors that automate or easy many of our daily tasks. This field takes into account the presence of an accelerometer, a gyroscope, a compass, and a barometer. Accelerometer and gyroscope. Accelerometers in mobile phones are used to detect the orientation of the phone.

What do you mean by G sensor?
Gravity sensor is an accelerometer. An accelerometer is a device that measures proper acceleration (“g-force”). … For example, an accelerometer at rest on the surface of the Earth will measure an acceleration g= 9.81 m/s2 straight upwards.

How do reverse parking sensors work?
Ultrasonic Sensors. These types emit radio or ultrasonic waves that bounce off of objects behind the vehicle, much like some animals use echolocation. … For example, some surface types can interfere with how sound waves reflect, or, if an object is too narrow or small to reflect sound waves, your sensor will not see it.

What is a proximity detector?
A proximity sensor is a sensor able to detect the presence of nearby objects without any physical contact. A proximity sensor often emits an electromagnetic field or a beam of electromagnetic radiation (infrared, for instance), and looks for changes in the field or return signal.

What is an inductive sensor?
An inductive proximity sensor is a type of non-contact electronic proximity sensor that is used to detect the position of metal objects. The sensing range of an inductive switch is dependent on the type of metal being detected.

What are electronic sensors used for?
A sensor is a device that detects and responds to some type of input from the physical environment. The specific input could be light, heat, motion, moisture, pressure, or any one of a great number of other environmental phenomena.

What is an active transducer?
Solution: A transducer is a device that converts input energy into output energy. Typically the output energy is differing in kind but related to the input. Active transducers generate electric current or voltage directly in response to environmental stimulation.

What is the difference between a sensor and transducer?
Sensors are almost always transducers but transducers are not necessarily sensors. A transducer is a device which converts signals from one form to another. This can include loudspeakers and linear positioners are well as physical quantity to electrical signal devices.

What is a temperature sensor used for?
A temperature sensor is a device, typically, a thermocouple or RTD, that provides for temperature measurement through an electrical signal. A thermocouple (T/C) is made from two dissimilar metals that generate electrical voltage in direct proportion to changes in temperature.

Capacitive Sensor :-

In electrical engineering, capacitive sensing (sometimes capacitance sensing) is a technology, based on capacitive coupling, that can detect and measure anything that is conductive or has a dielectric different from air.

Many types of sensors use capacitive sensing, including sensors to detect and measure proximity, position or displacement, humidity, fluid level, and acceleration. Human interface devices based on capacitive sensing, such as trackpads, can replace the computer mouse. Digital audio players, mobile phones, and tablet computers use capacitive sensing touchscreens as input devices. Capacitive sensors can also replace mechanical buttons.

Ultrasonic Sensor :-

What is an Ultrasonic Sensor?
An Ultrasonic sensor is a device that can measure the distance to an object by using sound waves. It measures distance by sending out a sound wave at a specific frequency and listening for that sound wave to bounce back. By recording the elapsed time between the sound wave being generated and the sound wave bouncing back, it is possible to calculate the distance between the sonar sensor and the object.

Since it is known that sound travels through air at about 344 m/s (1129 ft/s), you can take the time for the sound wave to return and multiply it by 344 meters (or 1129 feet) to find the total round-trip distance of the sound wave. Round-trip means that the sound wave traveled 2 times the distance to the object before it was detected by the sensor; it includes the ‘trip’ from the sonar sensor to the object AND the ‘trip’ from the object to the Ultrasonic sensor (after the sound wave bounced off the object). To find the distance to the object, simply divide the round-trip distance in half.

NOTE: The accuracy of Ultrasonic sensor can be affected by the temperature and humidity of the air it is being used in. However, for these tutorials and almost any project you will be using these sensors in, this change in accuracy will be negligible.

It is important to understand that some objects might not be detected by ultrasonic sensors. This is because some objects are shaped or positioned in such a way that the sound wave bounces off the object, but are deflected away from the Ultrasonic sensor. It is also possible for the object to be too small to reflect enough of the sound wave back to the sensor to be detected. Other objects can absorb the sound wave all together (cloth, carpeting, etc), which means that there is no way for the sensor to detect them accurately. These are important factors to consider when designing and programming a robot using an ultrasonic sensor.

Ultrasonic sensors are based on measuring the properties of sound waves with frequency above the human audible range. They are based on three physical principles: time of flight, the Doppler effect, and the attenuation of sound waves. Ultrasonic sensors are non-intrusive in that they do not require physical contact with their target, and can detect certain clear or shiny targets otherwise obscured to some vision-based sensors. On the other hand, their measurements are very sensitive to temperature and to the angle of the target.

Ultrasonic sensors “are based on the measurement of the properties of acoustic waves with frequencies above the human audible range,” often at roughly 40 kHz 1). They typically operate by generating a high-frequency pulse of sound, and then receiving and evaluating the properties of the echo pulse.

Three different properties of the received echo pulse may be evaluated, for different sensing purposes. They are:

Time of flight (for sensing distance)
Doppler shift (for sensing velocity)
Amplitude attenuation (for sensing distance, directionality, or attenuation coefficient)

The ultrasonic sensor uses this information along with the time difference between sending and receiving the sound pulse to determine the distance to an object.

Ultrasonic transducers are divided into three broad categories: transmitters, receivers and transceivers. Transmitters convert electrical signals into ultrasound, receivers convert ultrasound into electrical signals, and transceivers can both transmit and receive ultrasound.

In a similar way to radar and sonar, ultrasonic transducers are used in systems which evaluate targets by interpreting the reflected signals. For example, by measuring the time between sending a signal and receiving an echo the distance of an object can be calculated. Passive ultrasonic sensors are basically microphones that detect ultrasonic noise that is present under certain conditions.

Ultrasonic probes and ultrasonic baths apply ultrasonic energy to agitate particles in a wide range of materials

Optical Sensor :-
Electro-optical sensor
Electro-optical sensors are electronic detectors that convert light, or a change in light, into an electronic signal. They are used in many industrial and consumer applications, for example:

Lamps that turn on automatically in response to darkness
Position sensors that activate when an object interrupts a light beam
Flash detection, to synchronize one photographic flash to another
Photoelectric sensors that detect the distance, absence, or presence of an object

Types of Optical Sensors and Switches
There are many different kinds of optical sensors, the most common types are:

Photoconductive devices convert a change of incident light into a change of resistance.
Photovoltaics, commonly known as solar cells, convert an amount of incident light into an output voltage.
Photodiodes convert an amount of incident light into an output current.
Phototransistors are a type of bipolar transistor where the base-collector junction is exposed to light. This results in the same behaviour of a photodiode, but with an internal gain.
Optical Switches are usually used in optical fibers, where the electro-optic effect is used to switch one circuit to another. These switches can be implemented with, for example, microelectromechanical systems or piezoelectric systems.

Applications
Electro-optical sensors are used whenever light needs to be converted to energy. Because of this, electro-optical sensors can be seen almost anywhere. Common applications are smartphones where sensors are used to adjust screen brightness, and smartwatches in which sensors are used to measure the wearer’s heartbeat.

Optical sensors can be found in the energy field to monitor structures that generate, produce, distribute, and convert electrical power. The distributed and nonconductive nature of optical fibres makes optical sensors perfect for oil and gas applications, including pipeline monitoring. They can also be found in wind turbine blade monitoring, offshore platform monitoring, power line monitoring and downhole monitoring. Other applications include the civil and transportation fields such as bridge, airport landing strip, dam, railway, airplane, wing, fuel tank and ship hull monitoring.

Among other applications, optical switches can be found in thermal methods which vary the refraction index in one leg of an interferometer in order to switch the signal, MEMS approaches involving arrays of micromirrors that can deflect an optical signal to the appropriate receiver, piezoelectric beam steering liquid crystals which rotate polarized light depending on the applied electric field and acousto-optic methods which change the refraction index as a result of strain induced by an acoustic field to deflect light.

Another important application of optical sensor is to measure the concentration of different compounds by both visible and infrared spectroscopy.

Fibre Sensor :-

A fiber optic sensor is a sensor that uses optical fiber either as the sensing element (“intrinsic sensors”), or as a means of relaying signals from a remote sensor to the electronics that process the signals (“extrinsic sensors”). Fibers have many uses in remote sensing. Depending on the application, fiber may be used because of its small size, or because no electrical power is needed at the remote location, or because many sensors can be multiplexed along the length of a fiber by using light wavelength shift for each sensor, or by sensing the time delay as light passes along the fiber through each sensor. Time delay can be determined using a device such as an optical time-domain reflectometer and wavelength shift can be calculated using an instrument implementing optical frequency domain reflectometry.

Fiber optic sensors are also immune to electromagnetic interference, and do not conduct electricity so they can be used in places where there is high voltage electricity or flammable material such as jet fuel. Fiber optic sensors can be designed to withstand high temperatures as well.

Intrinsic sensors
Optical fibers can be used as sensors to measure strain, temperature, pressure and other quantities by modifying a fiber so that the quantity to be measured modulates the intensity, phase, polarization, wavelength or transit time of light in the fiber.

Extrinsic sensors

Extrinsic fiber optic sensors use an optical fiber cable, normally a multimode one, to transmit modulated light from either a non-fiber optical sensor, or an electronic sensor connected to an optical transmitter.

Diffuse Scan Sensors
These sensors are made of high-grade raw material and components procured from reliable vendors. Our range of photoelectric sensors includes diffuse scan

The Fibre Optical Sensors

1. INTRODUCTION
Recently, fibre optical sensors (FOS) have gained increased popularity and market acceptance. In comparison to conventional sensors they offer a number of distinct advantages which makes them unique for certain types of applications, mainly where conventional sensors are difficult or impossible to deploy or can not provide the same wealth of information.

2. TYPES OF FIBRE OPTICAL SENSORS
According to the spatial distribution of the measurand (the quantity to be measured), FOS can be classified as…

Point sensors: the measurement is carried out at a single point in space, but possibly multiple channels for addressing multiple points.
Examples are Fabry-Perot sensors and single Fibre Bragg Grating (FBG) sensors.

Integrated sensors: the measurement averages a physical parameter over a certain spatial section and provides a single value.
An example is a deformation sensor measuring strain over a long base length.

Quasi-distributed or multiplexed sensors: the measurand is determined at a number of fixed, discrete points along a single fibre optical cable. The most common example are multiplexed FBG’s.

Distributed sensor: the parameter of interest is measured with a certain spatial resolution at any point along a single optical cable.
Examples include systems based on Rayleigh, Raman and Brillouin scattering.

3. GENERAL ADVANTAGES OF FIBRE OPTICAL SENSORS

Completely passive: can be used in explosive environment.

Immune to electromagnetic interference: ideal for microwave environment.

Resistant to high temperatures and chemically reactive environment: ideal for harsh and hostile environment.

Small size: ideal for embedding and surface mounting.

High degree of biocompatibility, non-intrusive nature and electromagnetic immune: ideal for medical applications like intra-aortic balloon pumping.

Can monitor a wide range of physical and chemical parameters.

Potential for very high sensitivity, range and resolution.

Complete electrical insulation from high electrostatic potential.

Remote operation over several km lengths without any lead sensitivity: ideal for deployment in boreholes or measurements in hazardous environment.
Multiplexed and distributed sensors are unique in that they provide measurements at a large number of points along a single optical cable: ideal for minimising cable deployment and cable weight, or for monitoring extended structures like pipelines, dams etc.

In what follows we give a brief explanation of the working principles of optical fibres and each type of sensors.

4. OPTICAL FIBRES
An optical fibre consists of a thin, low-loss glass wire with a centre or core region having a slightly higher refractive index than its surrounding region or cladding.

A fiber optic sensor is a sensor that uses optical fiber either as the sensing element (“intrinsic sensors”), or as a means of relaying signals from a remote sensor to the electronics that process the signals (“extrinsic sensors”). Fibers have many uses in remote sensing.

How does optical sensors work?
Optical sensors work by converting light into an electronic signal. The sensor is attached to a measuring instrument and an electrical trigger. When light strikes the sensor, it trips the trigger, so a measurement is taken.

What is a fiber optic?
A technology that uses glass (or plastic) threads (fibers) to transmit data. A fiber optic cable consists of a bundle of glass threads, each of which is capable of transmitting messages modulated onto light waves.

What is an optical sensor?
An optical sensor is generally part of a larger system that integrates a source of light, a measuring device and the optical sensor. This is often connected to an electrical trigger. The trigger reacts to a change in the signal within the light sensor.

What is an optical detector?
Detectors perform the opposite function of light emitters. They convert optical signals back into electrical impulses that are used by the receiving end of the fiber optic data, video, or audio link. The most common detector is the semiconductor photodiode, which produces current in response to incident light.

 

What is optical proximity sensor?
Optical Proximity Sensors These sensors are more commonly known as light beam sensors of the thru-beam type or of the retro reflective type. Both sensor types are shown below. A complete optical proximity sensor includes a light source, and a sensor that detects the light.

 

How do heart rate monitor work?
Optical heart rate sensors use a methodology called photoplethysmography (PPG) to measure heart rate. PPG is a technical term for shining light into the skin and measuring the amount of light that is scattered by blood flow.

What is a heart rate sensor?
A comfortable heart rate sensor strap which you connect via bluetooth to your fitness app or training device. Monitor your real-time, accurate heart rate while you train, review and analyze it during or after workouts.

What is an optical switch?
In telecommunication, an optical switch is a switch that enables signals in optical fibers or integrated optical circuits (IOCs) to be selectively switched from one circuit to another.

How does a fiber optic cable work?
Imagine what they’d make of modern fiber-optic cables—”pipes” that can carry telephone calls and emails right around the world in a seventh of a second! Photo: Light pipe: fiber optics means sending light beams down thin strands of plastic or glass by making them bounce repeatedly off the walls

What is a sensor in electronics?
A sensor is a device that detects and responds to some type of input from the physical environment. The specific input could be light, heat, motion, moisture, pressure, or any one of a great number of other environmental phenomena.

Laser Sensor : –
Laser Sensors
Laser sensors can detect, count, trigger, map, profile, scan, and guide as well as verify levels, proximities and distances to practically anything you can think of. LTI’s laser sensors are ideal for many specific applications in Plant Management and Automation, Security and Surveillance, Vehicle Guidance and Automation and Traffic Management.

Laser sensors for collision avoidance
The variation in material characteristics or the difference in environmental conditions is typically the contributing factor of why a certain measurement technology won’t work. Some equipment and methods struggle to recognize a moving target in dusty conditions whereas others have difficulties obtaining a valid level measurement to liquids.

Considering all these factors and more, it would be nearly impossible to design an all-encompassing laser sensor that could work in a wide variety of scenarios. This is why Laser Technology has engineered a unique line of laser sensors with specific characteristics and capabilities that can overcome particular challenges.

All laser sensors are non-contact (a.ka. reflectorless), allowing you to measure a distance to a target or material without the need of reflective material. The other key to non-contact measurements is that the laser sensor can be aligned to the target from practically any distance or angle within its range. Sensors will also return an accurate measurement to more difficult targets, including most liquids and solids.

Laser sensors measuring bin levels
Some key benefits to infrared laser sensors are: fast data rates, small beam footprint, and ability to penetrate air-borne particulates, scanning capabilities, multiple target detection, and measurements to most surfaces and targets that are independent of incident angle.

All laser sensors are eye safe and highly configurable allowing the user to optimize and customize the measurement performance to meet demanding conditions easily, safely, reliably and inexpensively. Where other measurement alternatives fall short, non-contact, pulse-laser technology rises to the challenge.

How laser sensors measure up:

Easily identifies difficult targets such as liquids, non-reflective material and fast moving objects.
Makes non-contact and non-intrusive measurements without the need for frequent calibration.
Recognizes small targets at long distances, within narrow openings and from sharp angles.
Performs under temperature variations, background noise, vapor pressure and low dielectric or acoustically absorbing materials.

 

Conductive Sensor : –
In electrical engineering, capacitive sensing (sometimes capacitance sensing) is a technology, based on capacitive coupling, that can detect and measure anything that is conductive or has a dielectric different from air. In general, the measurement of conductivity is a rapid and inexpensive way of determining the ionic strength of a solution. Conductivity is used to measure the purity of water or the concentration of ionized chemicals in water. Conductivity sensors measure the ability of a solution to conduct an electrical current. It is the presence of ions in a solution that allow the solution to be conductive: the greater the concentration of ions, the greater the conductivity.

In electrical engineering, capacitive sensing (sometimes capacitance sensing) is a technology, based on capacitive coupling, that can detect and measure anything that is conductive or has a dielectric different from air.

Many types of sensors use capacitive sensing, including sensors to detect and measure proximity, position or displacement, humidity, fluid level, and acceleration. Human interface devices based on capacitive sensing, such as trackpads, can replace the computer mouse. Digital audio players, mobile phones, and tablet computers use capacitive sensing touchscreens as input devices. Capacitive sensors can also replace mechanical buttons.

 

Magnetic Sensor :-

MAGNETIC SENSORS
Magnetic sensors detect changes and disturbances in a magnetic field like flux, strength and direction. Other types of detection sensors work with characteristics like temperature, pressure, light. From established knowledge about the existing magnetic field and the data collected from sensors regarding changes and alterations, many things can be known. Rotation, angles, direction, presence and electrical current can all be monitored. Magnetic sensors are divided into two groups, those that measure the complete magnetic field and those that measure vector components of the field. The vector components are the individual points of the magnetic field. The techniques used to create these sensors involve various combinations of physics and electronics.

MEASURING A MAGNETIC FIELD
A magnetic field surrounds an electric current. The field is detectable by its force or interaction on electrical charges, magnets and magnetic products. The strength and direction of a magnetic field can be measured and documented. Fluctuations in that field are sensed and adjustments or changes are made in a machines response, a doctors decisions, the direction the navigational instrument gives or the response of a detection system. The Earth’s magnetic field is a great example. It is measured and tracked by magnetic sensors which are part of the navigational tools that Honeywell and other corporations design and manufacture. Most magnetic sensors are used for measurement in industrial processes, navigational tools, and scientific measuring.

MAGNETIC SENSING TECHNOLOGY
There are several types of technologies used to make a magnetic sensor work. Fluxgate, Hall Effect, magnetoresisitive, magnetoinductive, proton precession, optical pump, , nuclear precession, and SQUID (superconducting quantum interference devices) each have a different approach to using magnetic sensors. Magnetoresistive devices record electrical resistance of the magnetic field. Magnetoinductive are coils surrounding magnetic material whose ability to be permeated changes within the Earth’s magnetic field. Fluxgate measures magnetic fields against a known internally created magnetic based response that runs through a continually fluxing set of parameters. Each type of technology focuses on a particular area for detection, a measurement to be detected and way of recording changes.

THE SMALLEST MAGNETIC SENSOR
A recent discovery may allow improvements to magnetic sensors across the board. The NIST (National Institute of Standards And Technology) have revealed that combining layers of magnetic alloy with nano layers of silver increase magnetic sensitivity. Being able to use an extremely thin magnetic sensor (called thin films) is a necessity in applications found in medical devices, weapon detection and data storage.

Float Sensor :-
A float switch is a device used to detect the level of liquid within a tank. The switch may be used in a pump, an indicator, an alarm, or other devices.

How does a float sensor work?
The purpose of a float switch is to open or close a circuit as the level of a liquid rises or falls. Most float switches are “normally closed,” meaning the two wires coming from the top of the switch complete a circuit when the float is at its low point, resting on its bottom clip (for example, when a tank is dry).

What is a liquid level sensor?
Level sensors detect the level of liquids and other fluids and fluidized solids, including slurries, granular materials, and powders that exhibit an upper free surface.

What is a float switch in an air conditioner?
The fix for an overflow that the drain pan cannot handle is a safety float switch. If the moisture begins to collect in the drainage line, a small ball valve, within the safety switch, will begin to float thus transmitting a signal to the compressor unit to turn off.

What is the use of pressure switch?
A pressure switch is a form of switch that closes an electrical contact when a certain set pressure has been reached on its input. The switch may be designed to make contact either on pressure rise or on pressure fall.

What is the level switch?
A float switch is a device used to detect the level of liquid within a tank. The switch may be used in a pump, an indicator, an alarm, or other devices.

What is the level measurement?
Level measurement devices can detect, indicate, and/or help control liquid or solid levels. Level measurement devices can be separated into two categories: direct, or mechanical, measurement and electronic measurement.

What is the use of level transmitter?
A Level Transmitter is simply an instrument that provides continuous level measurement. Level transmitters can be used to determine the level of a given liquid or bulk-solid at any given time.

How does an automobile coolant level sensor work?
While manufacturers use different types of coolant-level sensors, the simplest is a float that activates a switch. If the coolant drops below the designated level, the switch opens, sending a signal to the indicator light. Manufacturers install these switches either in the coolant recovery tank or in the radiator.

What is ultrasonic level transmitter?
Sonic is the sound we can hear. Ultrasonic is the sound above human hearing range. Human can hear maximum up to a frequency of 20 KHz. Ultrasonic frequencies are above 20 KHz. Ultrasonic waves are used to measure level of liquids and solid objects in industries.

What is the principle of capacitance type level transmitter?
Capacitance level instruments operate on the basic principle of the variation of the electrical capacity of a capacitor formed by the sensor, the vessel wall and the dielectric material. A capacitor is made of two conductive plates which are isolated from each other by a dielectric.

What is the use of differential pressure switch?
The Differential Pressure Switch just like the pressure switch is a simple electro- mechanical device that operates on the basic principles of Levers and opposing forces. They are mainly used for sensing a difference in pressure between two points in a plant or system.

What is the function of the limit switch?
The limit switch then regulates the electrical circuit that controls the machine and its moving parts. These switches can be used as pilot devices for magnetic starter control circuits, allowing them to start, stop, slow down, or accelerate the functions of an electric motor.

Float switch

A float switch is a device used to detect the level of liquid within a tank. The switch may be used in a pump, an indicator, an alarm, or other devices.

Float switches range from small to large and may be as simple as a mercury switch inside a hinged float or as complex as a series of optical or conductance sensors producing discrete outputs as the liquid reaches many different levels within the tank. Perhaps the most common type of float switch is simply a float raising a rod that actuates a microswitch.

Tilt Sensors

Microelectromechanical systems

A MEMS-based magnetic field sensor is a small-scale microelectromechanical (MEMS) device for detecting and measuring magnetic fields. Many of these operate by detecting effects of the Lorentz force: a change in voltage or resonant frequency may be measured electronically, or a mechanical displacement may be measured optically. Compensation for temperature effects is necessary. Such instruments have medical and biomedical applications.

How does a pressure transmitter works?
A pressure transducer, often called a pressure transmitter, is a transducer that converts pressure into an analog electrical signal. Although there are various types of pressure transducers, one of the most common is the strain-gage base transducer.

How does an ultrasonic distance sensor work?
The Ultrasonic Sensor sends out a high-frequency sound pulse and then times how long it takes for the echo of the sound to reflect back. The sensor has 2 openings on its front. One opening transmits ultrasonic waves, (like a tiny speaker), the other receives them, (like a tiny microphone).

Loop Detectors :-

Induction loop

An induction or inductive loop is an electromagnetic communication or detection system which uses a moving magnet to induce an electric current in a nearby wire. Induction loops are used for transmission and reception of communication signals, or for detection of metal objects in metal detectors or vehicle presence indicators. A common modern use for induction loops is to provide hearing assistance to hearing-aid users.

Vehicle detection loops, called inductive-loop traffic detectors, can detect vehicles passing or arriving at a certain point, for instance approaching a traffic light or in motorway traffic. An insulated, electrically conducting loop is installed in the pavement.

How does an induction loop system work?
An induction loop system transmits an audio signal directly into a hearing aid via a magnetic field, greatly reducing background noise, competing sounds, reverberation and other acoustic distortions that reduce clarity of sound.

How does a stop light work?
These detectors are buried in or under the roadway. Inductive detector loops are the most common type. They are sensors buried in the road to detect the presence of traffic waiting at the light, and thus can reduce the time when a green signal is given to an empty road.

How does a hearing loop system work?
A hearing loop (sometimes called an audio induction loop) is a special type of sound system for use by people with hearing aids. The hearing loop provides a magnetic, wireless signal that is picked up by the hearing aid when it is set to ‘T’ (Telecoil) setting.

What is a sound loop?
Audio induction loop. … Audio induction loop systems, also called audio-frequency induction loops (AFILs) or hearing loops, are an assistive listening technology for individuals with reduced ranges of hearing.

Hot Metal Detector (HMD) :-

Series of optical sensor are designed to detect the presence of hot infrared emitting bodies. Typical applications are the material presence detection in hot wire rod, bar and section mills or in plate and hot strip mills, but they can be applied in any situation where hot objects should be detected. Series of sensors have been designed specifically for the steel industry and are capable of being directly installed in harsh environmental conditions. Several solutions are available in terms of mechanical arrangements (e.g. fiberoptic sensing head options), temperature ranges and field of view geometries.

Hot Metal Detectors (HMD) are used in many different applications throughout the metals rolling process, for target detection, tracking and length determination. They are also an essential component of cut-to-length systems.

ROLLING MILLS
To Control cut to length shearing, monitor hot rods, controlling roller tables, coil regulating, switching in crosscut hauler, monitor de-scaler, cooling beds, winder control, monitor edge washing, continuous casting or tracking of high speed wire.
Detection of Hot Metal or Hot Product in a Rod Mill, Bar Mall, Rolling Mill, Plate Mill, Roughing Mill, Reversing Mill, Hot Strip Mill or other Steel Mill and Industrial Applications.

 

Light Curtain :-
Safety Light curtains are opto-electronic devices that are used to safeguard personnel in the vicinity of moving machinery with the potential to cause harm such as presses, winders and palletisers. Safety Light curtains can be used as an alternative to mechanical barriers and other forms of traditional machine guarding. By reducing the need for physical guards and barriers, safety light curtains can increase the maintainability of the equipment they are guarding. The operability and efficiency of machinery can also be improved by the use of safety light curtains by, for example, allowing easier access for semi-automatic procedures.

Safety Light curtains fall into a category of equipment known as presence detection devices. Other common presence detection devices are pressure-sensitive safety mats and laser scanners (often used on Remotely Operated Vehicles (ROV) when in industrial settings). Most important application of safety relays is in automation industries dealing with robotic cell set up.

Safety Light curtains are supplied as a pair with a transmitter and receiver. The transmitter projects an array of parallel infrared light beams to the receiver which consists of a number of photoelectric cells. When an object breaks one or more of the beams a stop signal is sent to the guarded equipment.

The light beams emitted from the transmitter are sequenced, one after the other, and pulsed at a specific frequency. The receiver is designed to only accept the specific pulse and frequency from its dedicated transmitter. This enables the rejection of spurious infrared light and thus enhances their suitability as components within a safety system.

Typically, safety light curtains are connected to a safety relay which will remove motive power from the hazard in the event that an object is detected. Safety relays can be provided with muting functionality which enables the temporary disabling of the safety function to allow objects to pass through the safety light curtains without tripping the safety relay. This is particularly useful for machinery which has some semi-automatic procedures.

Flexible, cost-saving installation and maintenance with the highest safety
Safety light curtains reliably and cost-effectively protect against access into hazardous points and areas. Depending on the variant, different machine functions are integrated or can be selected via safe control solutions. The range from small and compact types to extremely robust and resistant variants that withstand special ambient conditions up to the highest safety level

Wind Sensors :-

Wind is measured using a so called anemometer. The term is derived from the Greek word anemos, meaning wind. For the measurement of wind speed and wind direction several principles may be used. At this moment wind sensors or anemometers can be divided into two types. Static ones based upon the ultrasonic principle and mechanical cup and vane types sensors. Observator offers a wide range of wind sensors with these two principles, which all have one thing in common: designed to be used within the hardest environmental conditions.

The Wind Sensor is a thermal anemometer based on a traditional technique for measuring wind speed. The technique is called the “hot-wire” technique, and involves heating an element to a constant temperature and then measuring the electrical power that is required to maintain the heated element at temperature as the wind changes. This measured electrical input is then directly proportional to the square of the wind speed.

Principle that makes the sensor function is the same as the traditional hot-wire technique. This technique excels at low to medium wind speed, and is the preferred technique for sensing indoor air movement, where the spinning cup anemometers typically seen on weather stations are ineffective. As an experimenters tool, the sensor is exquisitely sensitive, with a small puff of air being sensed at a distance of 18-24?. Possible applications include human breath detection, room occupancy detection, hvac system monitoring, weather stations and many more.

Wind Turbine Sensors
Wind Speed Sensors

Speed sensor

Speed sensors are machines used to detect the speed of an object, usually a transport vehicle. They include:

Wheel speed sensors
Speedometers
Pitometer logs
Pitot tubes
Airspeed indicators
Piezo sensors (e.g. in a road surface)
LIDAR
Ground speed radar
Doppler radar
ANPR (where vehicles are timed over a fixed distance)
Laser surface velocimeters for moving surfaces

 

all types of sensors etc.

 

pH/ORP sensors are based on two different measurement techniques: Conventional combinational and Differential Electrode Measurement Technique (DEMT). Our range of conventional combinational sensors can withstand extreme temperatures from -5°C to 140°C. They have large reference junctions to minimize clogging problems by process media.

Unlike run of the mill pH/ORP sensors we also provide the DEMT sensor technology. These DEMT sensors provide unsurpassed accuracy, reduce reference junction fouling, and virtually eliminate ground loop problems. A field reparable model is also available to reduce downtime. These sensors are certified for use in hazardous areas too.

Our range of analyzers and transmitters come with a wide array of functional capabilities and control strategies to suit your needs.

The 2-wire transmitters are certified by CCOE, Nagpur for meeting intrinsic safety standards to eliminate the need for flame proof enclosures.

For extreme pH and hence difficult to measure applications our success has greatly depended on our retraction assembly. Some of these difficult to measure applications where we have proved our pH/ORP systems are caustic chlorine, enzymatic reactions such as 6APA, malathione, cyanide processing, scrubber for acidic gases, high purity water ….

 

contacting conductivity sensors come in a range of cell constants from 0.01 to 10 enabling measurable conductivities upto 200 mS/cm. We also provide customised cell constants for your specific needs. Each of these sensors undergo stringent quality checks through precise measurements and tests hence providing accurate results. High pressure and temperature styles are also available. They have pressure ratings upto 150 bar and can withstand temperatures of 250°C. The sensors come in a variety of materials – titanium, graphite and stainless steel. Optional integral junction boxes are also available.

The analyzers can accept upto 2 sensor inputs and also are capable of accepting nearly all cell constants.

Some of the applications that we have successfully put our systems to use are high purity water, multi distill columns, oleum (65 %), phase separations, heavy water line upto 150 bar ….

 

electrodeless conductivity sensors come in a variety of materials – PP, PVDF and Hastelloy C. We are proud to be the first in the world to successfully introduce the Hastelloy C sensor. These sensors have pressure ratings upto 100 psig at 120°C and can withstand temperatures from 0°C to 200°C. Conductivities in the range of 0 – 2000 ms/cm can be measured using them.

The analyzers and transmitters are capable of measuring both conductivity as well as concentrations of various liquid medias. Total of 9 most widely used in-built concentration tables have been pre-programmed. In addition to these, a user-defined table is also available to the user for his specific application.

Few of the applications in which we have successfully proven our electrodeless conductivity systems are pan evaporation (sugar industry), acid/alkali/salt concentrations, phase separations, CIP ….

Our dissolved oxygen sensor technology are based on two different types: Amperometric – Polarographic and Electro-chemical. These have a modular style of construction, which has served the user better in terms of reducing downtime through their rebuildable capability.

Our model 672D analyzer, an original research product from BI, is truly of world class quality and performance. In fact 672D is a case of reverse technology transfer, that has been acknowledged and accepted by our international partner for marketing overseas.

Few of the applications where our dissolved oxygen systems have been successfully used are active bed (aerated lagoons), fish ponds, swimming pools ….

 

level measurement systems are based on capacitance and RF technology. These systems can be used for both conductive as well as non-conductive liquid medias. They can be used in liquid medias with conductivities as low as 1 µS/cm.

Level sensors are available in a variety of lengths and materials which are customized to meet specific needs. Sensors have temperature ratings upto 232°C and can withstand pressures of 68 bar at 65.5°C derated to 0 bar @ 176.6°C. The electronics are housed in an explosion proof designed enclosure allowing their use in all environments.

Our systems have a triangular wave harmonic recognition and rejection that provides greater accuracy than conventional sinusoidal admittance error correction techniques. This reduces the error effect of conductive material build-up on the electrode surface.

Some of the applications where our level systems have been successfully used are phase separation, HCl tanks (MOC Hastelloy C and Teflon), various organic solvents storage tanks, pure water ….

Dedicated systems specifically for the purpose of fermentation control application form an integral part of the BI product line.

pH & DO being the most widely measured analytical parameters in the fermentation process industry, special focus has been paid to analyzing these parameters. In fact as a service to this industry BI along with a leading industrial fermentation expert has written an article “Measurement and control of Fermentors” that has been published in the Chemical Industry Digest (Issue: Sept-Oct 2001) giving details of the above.

Other measurement and control capabilities include RPM, Antifoam, Airflow and Back pressure. In addition our systems are built on a batch concept. This enables the user to statistically analyze selective parameters from batch to batch.

Few of the fermentation based processes where our systems have been used are Vitamin B12, Enzymes, Recombinant vaccines, Yeast, Recombinant proteins, Rifampicin ….