Infrared Sensor And Working Principle

An Infrared Sensor is an electronic device that emits some radiation in order to sense some aspects of the surroundings. The infrared sensor can measure the heat of an object and also detects the motion. These types of sensors measures only IR radiation, rather than emitting it that is called as a passive infrared sensor. Usually in the IR spectrum, all the objects radiate some form of thermal radiations. These types of radiations are invisible to our eyes that can be detected by an IR sensor. The emitter is simply an infrared LED (Light Emitting Diode) and the detector is simply an infrared photo diode which is sensitive to infrared light of the same wavelength as that emitted by the infrared LED. When infrared light falls on the photo diode, the resistances and these output voltages, change in proportion to the magnitude of the infrared light received.

An Infrared  sensor is a device that detects moving objects, particularly people. An Infrared  sensor is often integrated as a component of a system that automatically performs a task or alerts a user of motion in an area. An electronic Infrared  sensor contains an optical sensor, and in many cases a transmitter for illumination. However, a Infrared  sensor only senses a signal emitted by the moving object itself. Changes in the optical signal in the device’s proximity are interpreted by the electronics based system. Most inexpensive Infrared  sensor can detect up to distances of at least 15 feet (5 meters).

IR Sensor Working Principle

1.     Infrared spectrum

2.     Transmitter

3.     Receiver

4.     Reflection by object

5.     Voltage level

IR Sensor Circuit Diagram and Working Principle

An IR sensor circuit is one of the basic and popular sensor modules in an electronic device. This IR sensor is analogous to human’s visionary senses, which can be used to detect obstacles and it is one of the common applications in real time.