Table of Contents
What are Sensors?
The sensor may be defined as a machine, module, subsystem, or device whose purpose is to detect changes and events in the environment. The information regarding these changes is further sent to various other electronics mostly comprising of a computer processor. A sensor is always used along with an electronic device.
Sensors are used in various everyday objects comprising of lamps with touch sensation which dim and light up by touching the base and touch-sensitive elevator buttons. With time, there have been advances in micromachinery and microcontroller platforms that are easy to use.
With time, the uses of sensors have increased beyond pressure or flow measurement and traditional fields of temperature. Analog sensors such as force-sensing resistors and potentiometers are widely in use even today.
The applications comprise airplanes and aerospace, medicine, cars, manufacturing and machinery, robotics, and various other aspects related to daily life. There are various sensors available that are used for measuring the physical and chemical properties of materials.
Now let’s read about the classification of sensors after which we will go through the types of sensors and how sensors work.
Classification of Sensors
Sensors are classified on the basis of the output signal, physical parameters measured by them, and various other points. Sensors on the basis of the output signal are classified into analog and digital output sensors.
The output given by the sensors in the case of analog output sensors is an analog voltage that can be measured and used for determining the required physical parameter. This is done by making use of the sensor’s transfer function. It may be resistive, capacitive, or anything which is analog.
The digital data which can be read via parallel or serial communication buses is the output of digital output sensors. The format for the data, in this case, is demonstrated in the sensor’s datasheet. An accelerometer sensor is an example of a digital sensor that is used for sending the output data by using the I2C two-wire bus.
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The sensors are further classified on the basis of physical parameters; these types may be used for measuring anything. The most common sensors are tilt sensor, magnetic sensor, cameras, color sensor, pressure sensor, fingerprint sensor, current sensor, light sensor, etc.
Different Types of Sensors with Their Applications
In daily life, it has become our habit to implement various types of sensors frequently in the power systems comprising of load control systems, electrical and electronics appliances, and industrial and home automation. All types of sensors are further divided into analog and digital sensors.
However, there are few types of sensors that are used in electronic applications such as pressure sensors, touch sensors, IR sensors, ultrasonic sensors, temperature sensors, proximity sensors, and so on.
Temperature Sensors:
Temperature is the commonly measured environmental quantity for various reasons. There are different types of temperature sensors that are used for measuring temperature such as thermistors, resistance temperature detectors, thermocouples, semiconductor temperature sensors, and so on.
On the basis of requirements, various types of sensors are used for the purpose of measuring temperature in different applications. A simple temperature sensor with a circuit may be used for switching the load on and off at a specific temperature.
This temperature is detected by the temperature sensor, in these cases, a thermistor is put to use. The temperature sensor circuit comprises a thermistor, transistor, relay, and battery. The temperature sensor activates the relay by detecting the required temperature.
The relay switches on the load that is connected to it which can be AC or DC. This circuit may be further utilized for the purpose of controlling the fan on the basis of temperature. Primarily, this type of sensor may be further classified into various other types such as digital temperature sensors, thermistors, and so on.
IR Sensors:
The small photo chips comprising of photocells that are used for detecting and emitting infrared light are termed IR sensors. These sensors are most commonly used for the purpose of designing remote-control technology.
These sensors may be used for detecting various obstacles of the robotic vehicle and controlling the direction of the same. There are different types of sensors that might be used for the detection of infrared lights.
A simple example of an IR sensor circuit that we use in our day-to-day life is a TV remote control. It comprises IR receiver circuits and IR emitter circuits that may be designed. The IR emitter circuit is used as a remote by the user for the purpose of emitting infrared light.
This infrared light is transmitted or sent to the IR receiver circuit which interfaces to the devices such as IR remote-controlled robots or a TV. These sensors are further used for designing television remote controls.
A TV remote is an example of a simple IR sensor-based electronics project which is used for the purpose of controlling a robotic vehicle in remote areas by using IR or TV remote. This type of TV remote is being utilized for sending commands to the robotic vehicle.
Ultrasonic Sensor:
An ultrasonic sensor or transceiver is a transducer that works on the principle alike radar or sonar and is known for estimating the attributes of the target by interpreting. These sensors are classified as active and passive ultrasonic sensors and maybe differentiated on their working.
The active ultrasonic sensors are known for generating high-frequency sound waves that are received back by the ultrasonic sensor for the evaluation of echo. The time interval taken for receiving and transmitting the echo helps in the determination of the distance to an object.
However, the passive ultrasonic sensors are merely used for the detection of ultrasonic noise whose presence can be found in specific conditions. When it comes to the practical application of an ultrasonic sensor with a circuit, it may also be used as an ultrasonic distance sensor circuit.
Touch Sensor:
The switches that are activated by touch may be said to have touch sensors. These sensors are classified into different types on the basis of their touch-type such as piezo touch switch, capacitance touch switch, and resistance touch switch.
For the purpose of controlling the load, a touch-sensitive load is designed. The touch-controlled load switch which is touch sensor principle-based comprises various blocks such as touch sensor plate, load, relay, and power supply block.
Proximity Sensor:
The proximity sensor is a type of IoT sensor in which the existence and non-existence of the surrounding objects are identified. After this, the detected signal is converted into a form that the user understands.
This type of sensor is mainly applied in the retail domain where any movement is found out and an association is present between the consumer and product. The users are provided with quick notifications related to exclusive offers and discount updates of the products in which they are interested.
Chemical Sensor:
A chemical sensor helps in determining various kinds of changes in liquid and for detecting the air chemical variations. These are mainly put to use in bigger cities and towns as it is important to look after the changes for providing safety to the people.
This type of sensor is essentially implemented in commercially atmospheric observation. It is used for processing management which may comprise of fortuitously or intentionally evolved chemicals, radioactive exposure, pharmaceutical industries, and reusable operations in space stations.
The most commonly used chemical sensors include chemical FET, electrochemical gas type, chemi resistor, non-dispersive IR, zinc oxide nanorod, and fluorescent chloride type.
Gas Sensor:
Gas sensors are similar to chemical sensors but are specially implemented for observing modifications in the quality of air. This is done to find out which types of gases are present in it. This sensor is being used in multiple domains such as health, manufacturing, agriculture, for supervision of gas in coal industries, chemical laboratory investigations, etc.
Some of the gas sensors that have been put to use include hydrogen type, hygrometer, carbon-dioxide sensor, ozone monitoring type, air pollution type, gas detection type, etc.
Humidity Sensors:
Humidity is used for defining the vapor present in the atmosphere or in gaseous substances. Humidity sensors are used as temperature sensors as the manufacturing operations require similar operating conditions. By measuring humidity, it can be ensured that the complete procedure will pass away easily.
In case of modification, immediate action can be taken as these sensors are known for quickly identifying the variations. There are numerous domains in which these are used such as ventilators, residential and commercial use for heating purposes, etc. Some other domains include meteorology, greenhouses, automobile, painting, coating industries, and hospitals.
Acceleration Sensor:
An acceleration sensor is used for calculating the acceleration and angular values. The accelerometer is primarily used for calculating acceleration. There are two types of forces that create an impact on the accelerometer; these are static force and dynamic force.
These sensors are present in numerous configurations and their type of selection is dependent on the industry’s requirement. There are few parameters that are required to be checked before selecting the sensors such as total number of axes, bandwidth, sensitivity, type of outputs, etc.
Sound Sensor:
Sound sensors can generally be identified as the microphone devices that are used for delivering the corresponding level of voltage and sound on the basis of the sound level detection. By implementing the sound sensor, a small robot may be manufactured for navigation on the basis of sound received.
In comparison to light sensors, the design process of sound sensors is complicated. The reason being the delivery of minimal voltage difference by them. This is further to be amplified for providing voltage variation that is measurable.
Various other sensors include a light sensor, tactile sensors, force sensors, etc. The types of sensors used in building include motion detection sensors, camera sensors, gas sensors, smoke and fire detection sensors, electric voltage and current sensors, and temperature sensors.
Uses of Sensors
If we look around carefully, sensors are used in many products that we use in our day-to-day life. Sensors are used in various industries comprising automotive, medical, aerospace, defense, and agriculture.
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Position sensors are used for the purpose of measuring movement, displacement, and position and maybe rotary or linear. These are used for controlling the throttle, measuring wind direction, positioning the ramp and bridge, simulating flights, and steering angle measurement.
Pressure sensors are being used for measuring pressure and can be a differential, gauge, or absolute. The most common types of pressure sensors that are used comprise transducers which are also known as pressure switches or pressure transmitters.
Some of the areas of pressure sensor application are oil pressure, tire pressure, vehicle braking systems, oil pressure, fans, filters, and diesel and engines applications. The force sensors also known as load cells or weight sensors are used for weighing applications in scales.
The weight sensors are known for giving the exact weight measurement by measuring the amount of force that is being applied. The load sensors are used in counting scales, hopper scales, platform scales, tank weighing, and on-boarding weighing.
Temperature sensors are put to use when it comes to monitoring and measuring the temperature of liquid, solid, and gas. It is the most commonly used sensor in homes and it is used in various shapes and sizes for serving different purposes.
This type of sensor is used in motors, surface plates, computers, industrial equipment, electrical radiators, exhaust gas monitoring, and home appliances. Sensors are highly beneficial and are used in various equipment used in our daily lives.
Applications of Digital Sensors
Digital sensors are the electrochemical sensors or electronic sensors in which the transmission and conversion of data take place. Digital sensors are known to have overcome the drawbacks present in analog sensors and have slowly begun to replace them.
Digital sensors are of different types such as digital accelerometers and digital temperature sensors. A digital accelerometer is known for generating variable frequency square wave output termed pulse-width modulation. In this, the readings are taken at a fixed rate by the pulse width modulated accelerometer.
A digital temperature sensor is known for providing device temperature with 9-bit temperature readings. It is known for acting as a thermostat with the presence of three thermal alarm outputs. It is being considered as a digital temperature control system that uses digital temperature sensors.
This control system has various advantages and provides accurate results in comparison to the analog temperature control system. A digital temperature control system is capable of providing a temperature display and switches off when the temperature exceeds a set point.
How do Sensors work?
Sensors are known to react as per the changing physical conditions by bringing a change in their electrical properties. It has been observed that artificial sensors in most cases rely on electronic systems for analyzing, capturing, and relaying environment information.
In simple words, it can be said that a sensor converts the stimuli such as sound, motion, heat, and light into electrical signals. These signals are passed through an interface that further converts these into a binary code passing them on to a computer to get processed.
Mostly, the sensors act as a switch and are used for controlling the flow of electric charges passing via the circuit. Switches form an important part of electronics as these are known for changing the state of the circuit.
The components present in sensors such as transistors, diodes, and integrated circuits or chips consist of semiconducting material. These materials are included in the sensor circuits so that they can be used as switches.
Mostly, sensors use radiation such as laser or light, infrared radio waves, or other waves such as ultrasonic ones for detecting the changes and objects present in the environment. This is possible if they have an energy source that assists them in emitting radiation in the direction of their target object.
This radiation is reflected back by the object and gets detected by the sensor; it is termed an active sensor. Passive sensors don’t send radiation or waves that are their own and detect what is being emitted by the target objects such as thermal infrared radiation, heat, or radiation from external sources like Sun reflected off the objects.
Pros and Cons of Different Sensors
Now let’s go through the pros of different sensors. When it comes to a touch sensor, the axle hole present in the sensor area may be used for creating its own bumper. The color sensor is known for detecting color, avoiding ambient light, and following lines.
The gyro sensor can be used for accurately turning and measuring the robot turning. An infrared sensor helps in finding the beacon and remote receiver. It is known for working and helping in measuring the proximity accurately.
An ultrasonic sensor measures in and cm and provides accurate distance measurement and wall following. These were the pros of different sensors, let’s know the cons of different sensors. The con in the case of a touch sensor is that the object must touch the sensor’s red part and its sensor area is small.
The color sensor is known to be reliable only when it is at a close range and the light color that it detects is white. In the case of a gyro sensor, the robot is required to be still when it is plugged. It can be unreliable and touch many times.
The other cons of different sensors include the sound of ultrasonic which may interfere with the sensor. The infrared sensor is not allowed in FLL and is not measured in cm or in. Hope you have received a great insight regarding sensors through this blog.
