The sensor is a sophisticated device that is frequently used to sense and respond to electrical (or) optical signals. Usually, the output of the sensor will be in the form of an electrical signal or optical signal. In our daily life, we use different types of sensors frequently in various applications like the Infrared sensor is used to operate the TV remote, PIR sensor is used in automatic door opening and closing, LDR sensor is used in street lighting system, etc. In this article, e will discuss a few kinds of sensors and their uses in brief.
Different Types of Sensors and Their Applications
The most frequently used types of sensors for making electrical projects are classified based on the quantities, namely IR (infrared), speed, PIR (passive infrared), temperature, touch, ultrasonic sensors.
What is a Speed Sensor?
The speed sensor is used to detect the speed of an object or vehicle. There are different kinds of sensors to detect the speed like speedometers, Wheel speed sensors, LIDAR, ground speed radar, Doppler radar, pitot tubes, airspeed indicators, and so on.
Speed Sensor Application
The typical application of speed sensor is speed synchronization of multiple motors in industries using wireless technology based on PIC microcontroller. One of the several motors in the industry is considered as the main motor which performs as transmitters and other motors acting as receivers, will track the motor’s speed. The motors used in this project are BLDC motors that are controlled using PWM with the RF (radio frequency) wireless communication mode.
Reference RPM is given to each motor shaft which has an IR sensor mounted and a closed loop is found by feeding this o/p to the microcontroller in the circuit. Full speed will show on the display unit and the mandatory speed of all motors can be attained by giving the chosen percentage using the keypad. The given percentage is matched with running RPM by keeping appropriate DC power to the motor with automatic change of pulse width o/p of the microcontroller.
Thus, by changing the speed of transmitting motor, we can change the speed of all motors using this technology
What is a Temperature Sensor?
A sensor which gives the measurement of temperature as an electrical signal is termed as Temperature sensor.This electrical signal will be in the form of electrical voltage and is proportional to the temperature measurement.
There are different kinds of temperature sensors used for measuring temperature, namely Contact type, Non-contact type temperature sensors. These two are again divided as Mechanical temperature sensors such as Thermometer & Bimetal. Electrical temperature sensors such as Thermistor, Resistance Thermometer, Thermocouple, and Si bandgap temperature sensor.
Temperature Sensor Application
The design of “Industrial Temperature Controller” for adjusting the temperature of devices used in industrial applications is one of the often used practical applications. In this circuit, IC DS1621 is a digital thermometer used as a temperature sensor, which gives 9-bit temperature readings. This circuit mainly comprises of 8051 microcontrollers, temperature sensor, EEPROM, LCD display and other required electrical and electronic components.
The LCD is used to show temperatures in the range of -55degress to +125degrees. EEPROM is used to store pre-defined temperature settings by an operator through the 8051 series microcontroller. The contact of the relay is used to load, is driven by the microcontroller using a transistor driver.
What is a PIR Sensor?
A PIR sensor is used to measure the IR radiation produced from objects in its field of view. Every object has a temperature that emits heat energy in the radiation form, that radiates at infrared wavelengths which are unseen to the human eye but can be noticed by special purpose electronic devices like PIR motion detectors.
PIR Sensor Application
The typical application of PIR sensor is an Automatic Door Opening System, which is proposed for automatic door opening operations based on body movement near the door. PIR sensor-based automatic door opening system is built with an 8051 microcontroller, PIR sensor, a driver IC, a door motor.
If any of the body movement is present nearby the door, then IR radiation produced by the body will make the sensor to generate sensing signal which is fed to 8051 series microcontroller.
Then the door motor is operated and then controlled by the microcontroller through driver IC. So, if anyone comes close to the door, then a signal will be sent by the microcontroller for door opening and a time delay is fixed for closing door automatically. The proposed system is projected for operating and closing the doors at public places like theaters, shopping malls, and hotels.
What is an Ultrasonic Sensor?
The principle of the ultrasonic sensor is like radar in which clarification of echoes from radio to estimate the qualities of a target by producing the high-frequency sound waves (around 40kHz).The transducer is used to convert energy into ultrasound with ranges above the range of human hearing range is named an ultrasonic transducer.
Application of Ultrasonic Sensor
The typical application of the ultrasonic sensor is the distance measurement at unreachable areas. This circuit contains an ultrasonic module, LCD display, and 8051 series microcontroller. The ultrasonic module is interfaced with the 8051 series microcontroller and this transducer comprises a transmitter and receiver.
The waves transmitted by the transducer are received back again after the waves are reflected back from the object. The velocity of sound is considered for calculating the time taken for sending and receiving waves. The distance is calculated by executing a program on the microcontroller, and then it is displayed on the LCD display.
What is a Touch Sensor?
The touch sensor is a switch that can be activated by the touch. There are different kinds of touch sensors that are categorized based on the type of touches like a resistance touch switch, capacitance touch switch, and a piezo touch switch.
Touch Sensor Application
A touch sensitive load is intended to control the load. The touch controlled load switch project block diagram is shown in the figure.
The block diagram of touch controlled load switch consists of various blocks like power supply block, 555 timers, touch sensor plate or touch plate, relay, and load as shown in the block diagram of touch controlled load switch.
The 555 timer IC is used in the circuit that is connected in monostable mode. This circuit is used for switching ON a load by driving a relay for a fixed time duration. The trigger pin of the IC is connected to the touch plate, thus this IC can be activated by touch.
Whenever 555 timers is activated by touch it gives logic high for a fixed time interval. This fixed time interval can be changed by varying the RC time constant which is connected to the timer. Thus, the output of the timer drives the load using the relay and the load turns off automatically after fixed time duration.
Similarly, we can develop simple and innovative engineering projects different types of sensors For designing different types of sensor-based projects on your own. You can also approach us for technical help by posting your ideas in the comments section below. Here is a question for you, what are impact sensors?