• A Potentiometer is a 3 terminal variable resistor in which the resistance is manually varied to control the flow of electric current. A potentiometer acts as an adjustable voltage divider.

• To know more about the working principle of a potentiometer, click on the link below:

https://www.electrical4u.com/potentiometer/

• A flex sensor or a bend sensor is a low-cost and easy-to-use sensor specifically designed to measure the amount of deflection or bending.

• To know more about the working principle and application of the flex sensor click on the links below:

https://lastminuteengineers.com/flex-sensor-arduino-tutorial/

https://www.electronicshub.org/interfacing-flex-sensor-with-arduino/

• A force sensitive resistor (FSR) is a material that changes its resistance when a force or pressure is applied. A conductive film is an example of such force resistance material. In other words, force sensitive resistor is a sensor that allows you to detect physical pressure, squeezing and weight.

• To know more about the working principle and application of force sensitive resistor click on the links below:

https://learn.adafruit.com/force-sensitive-resistor-fsr/using-an-fsr

https://lastminuteengineers.com/fsr-arduino-tutorial/

• LDR (Light Dependent Resistor) sensor

• A Light Dependent Resistor (also known as a photoresistor or LDR) is a device whose resistivity is a function of the incident electromagnetic radiation. Hence, they are light-sensitive devices. They are also called as photoconductors, photoconductive cells or simply photocells.

• To know about the working principle and applications of LDR click on the link below:

https://www.electrical4u.com/light-dependent-resistor-ldr-working-principle-of-ldr/

• A water level sensor is a device used to sense the level of liquid within a tank, it may actuate a pump, an indicator, an alarm, or other device. A float switch is a device used to sense the level of liquid within a tank. The switch may actuate a pump, an indicator, an alarm, or other device. When water flows through the valve it rotates the rotor. By this, the change can be observed in the speed of the motor.

• To know more about the working principle and application of a water level sensor click on the links below:

https://lastminuteengineers.com/water-level-sensor-arduino-tutorial/

https://create.arduino.cc/projecthub/123lYT/simple-water-level-sensor-with-led-ebf3f7

• Water flow sensor consists of a plastic valve from which water can pass. A water rotor along with a hall effect sensor is present the sense and measure the water flow.

• To know more about the working principle and application of water flow sensor click on the inks below:

https://www.electroschematics.com/working-with-water-flow-sensors-arduino/

https://www.instructables.com/id/How-to-Use-Water-Flow-Sensor-Arduino-Tutorial/

• A rain sensor or rain switch is a switching device activated by rainfall. There are two main applications for rain sensors. The first is a water conservation device connected to an automatic irrigation system that causes the system to shut down in the event of rainfall.

• The alternating pattern on the sensor is a highly resistive circuit, and when water falls on the circuit, it provides a less resistive path for the current to flow, resulting in a decrease in the resistance.

• To know more about the working principle and application of rainwater sensor click on the links below:

https://lastminuteengineers.com/rain-sensor-arduino-tutorial/

https://create.arduino.cc/projecthub/MisterBotBreak/how-to-use-a-rain-sensor-bcecd9

• The soil moisture sensor is a kind of sensor used to gauge the volumetric content of water within the soil.

• These sensors measure the volumetric water content not directly with the help of some other rules of soil like dielectric constant, electrical resistance, otherwise interaction with neutrons, and replacement of the moisture content.

• Two conductive probes given in the sensor is immersed inside the soil and if the moisture content in the soil is high, the resistance between probes will be less.

• To know more about the working principle and applications of rainwater sensor click on the links below:

https://lastminuteengineers.com/soil-moisture-sensor-arduino-tutorial/

https://create.arduino.cc/projecthub/MisterBotBreak/how-to-use-a-soil-moisture-sensor-ce769b

• MQ2 gas sensor is a robust Gas sensor suitable for sensing LPG, Smoke, Alcohol, Propane, Hydrogen, Methane and Carbon Monoxide concentrations in the air.

• To know more about working principle and application of MQ2 gas sensor, click on the links below:

https://lastminuteengineers.com/mq2-gas-senser-arduino-tutorial/

https://create.arduino.cc/projecthub/Aritro/smoke-detection-using-mq-2-gas-sensor-79c54a

• DHT humidity and temperature sensor is a type of sensor that can be used to calculate temperature and humidity of surroundings. With a capacitive humidity sensor, a thermistor and a microchip, this sensor can measure temperature and humidity in the atmosphere.

• It can be used as a digital as well as an analog sensor. It has two variants named DHT11 and DHT22. They both come with varying properties and accuracy.

• To know more about the working procedure and applications of DHT sensors, click on the links below:

https://lastminuteengineers.com/dht11-dht22-arduino-tutorial/

https://howtomechatronics.com/tutorials/arduino/dht11-dht22-sensors-temperature-and-humidity-tutorial-using-arduino/

https://create.arduino.cc/projecthub/techno_z/dht11-temperature-humidity-sensor-98b03b

• A barometric pressure sensor is a sensor that detects atmospheric pressure. This sensor can measure temperature and air pressure, and that data can be used to determine the altitude from sea level. It is generally called as BMP180 barometric and pressure sensor.

• To know more about the working principle an application of barometric pressure sensor, click on the links below:

https://lastminuteengineers.com/bmp180-arduino-tutorial/

https://create.arduino.cc/projecthub/electropeak/determining-the-pressure-and-altitude-using-gy-68-bmp180-and-93fd6f

• A sound sensor uses a microphone to detect sound and has an inbuilt potentiometer which you can use to increase or decrease the sensitivity of the sound reception. This can be used in a variety of application where the use of sound reception is required.

• With a vibrating diaphragm due to sound waves, this sensor can measure the level of sound present in the atmosphere.

• To know more about the working process, hardware overview and applications of a sound sensor, click on the link below:

https://lastminuteengineers.com/sound-sensor-arduino-tutorial/

https://create.arduino.cc/projecthub/iotboys/control-led-by-clap-using-arduino-and-sound-sensor-e31809

• This sensor is used to measure distance of any object from itself using ultrasonic sound waves. This sensor is named as HC-SR04 Ultrasonic sensor.

• To know more about working procedure and applications of the sensor, click on the links below:

https://lastminuteengineers.com/arduino-sr04-ultrasonic-sensor-tutorial/

https://create.arduino.cc/projecthub/abdularbi17/ultrasonic-sensor-hc-sr04-with-arduino-tutorial-327ff6

• An infrared sensor is an electronic device, that emits in order to sense some aspects of the surroundings. An IR sensor can measure the heat of an object as well as detects the motion. These types of sensors measure only infrared radiation, rather than emitting it that is called a passive IR sensor. Usually, in the infrared spectrum, all the objects radiate some form of thermal radiation.

• IR (Infrared) sensor is a distance sensor and works on the phenomenon of reflection of Infrared light.

• To know more about the working principle and its application click on the links below:

https://www.elprocus.com/infrared-ir-sensor-circuit-and-working/#:~:text=An%20infrared%20sensor%20is%20an,called%20a%20passive%20IR%20sensor.

https://create.arduino.cc/projecthub/Raushancpr/arduino-with-ir-sensor-1579b6

• PIR sensor detects a human being moving around within approximately 10m from the sensor. This is an average value, as the actual detection range is between 5m and 12m. PIR is fundamentally made of a pyroelectric sensor, which can detect levels of infrared radiation.

• Passive Infrared (PIR) sensor detects motion. It can be used in projects like Burglar alert alarm.

• To know more about the working principle and applications of the PIR sensor, click on the links below:

https://lastminuteengineers.com/pir-sensor-arduino-tutorial/

https://www.elprocus.com/pir-sensor-basics-applications/

https://create.arduino.cc/projecthub/electropeak/pir-motion-sensor-how-to-use-pirs-w-arduino-raspberry-pi-18d7fa

• The Pulse Sensor is a well-designed low-power plug-and-play heart-rate sensor for the Arduino. It can be used by students, artists, athletes, manufacturers, and game & mobile developers who want to incorporate live heart-rate data into their projects.

• And the best part is that this sensor plugs right into Arduino and easily clips onto a fingertip or earlobe. It is also super small (button-shaped) with holes, so it can be sewn into fabric.

• To know more about the working principle, hardware overview and applications of the sensor, click on the links below:

https://lastminuteengineers.com/pulse-sensor-arduino-tutorial/

https://create.arduino.cc/projecthub/Ingeimaks/diy-heart-rate-sensor-a96e89

• The Hall Effect is the most common method of measuring magnetic field and this sensor is used to detect the magnetic field with the help of a current conductor element inside it.

• Top know more about the working principle and application of hall effect sensor, click on the links below:

https://howtomechatronics.com/how-it-works/electrical-engineering/hall-effect-hall-effect-sensors-work/

https://www.electronics-tutorials.ws/electromagnetism/hall-effect.html

https://create.arduino.cc/projecthub/instrumentation-system/acs712-current-sensor-87b4a6

• The joystick module has a greater advantage when it comes to applications used in robotics. This module enables directional movement on different axis.

• The joystick module has a variable resistor on two different axes. It gives you analog output on 2 pins.

• To know more about the hardware configuration, working principle and application of the joystick module, click on the links below:

https://lastminuteengineers.com/joystick-interfacing-arduino-processing/

https://components101.com/modules/joystick-module

https://create.arduino.cc/projecthub/MisterBotBreak/how-to-use-a-joystick-with-serial-monitor-1f04f0

• Touch Sensors are the electronic sensors that can detect touch. They operate as a switch when touched.

• This is a touch sensor which gives you digital output when human finger touches the sensing part.

• To know more about the working principle, hardware configuration and application of capacitive touch sensor module, click on the links below:

https://www.electronicshub.org/touch-sensors/

https://www.elprocus.com/touch-sensor-working-and-its-appplications/

https://www.watelectronics.com/what-is-touch-sensor-working-its-applications/

https://create.arduino.cc/projecthub/CodeRocks/touch-sensor-01d36e

• The first ever sensor invented was by Warren Johnson and it was an electric thermostat.

• It was used to measure atmospheric temperature.

• It was launched in market in 1883.