IR Sensor Pinout Working Details:
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.
IR Sensor or Infrared Sensor has two main parts. IR Transmitter and IR Reciever. The work of IR transmitter or Infrared transmitter is to transmit the infrared waves whereas the work of IR receiver is to receive these infrared waves.
IR receiver constantly sends digital data in the form of 0 or 1 to Vout pin of the sensor. If there is an object in front of IR sensor, the transmitted infrared waves from IR transmitter reflects from that object and is received by the IR receiver. IR sensor gives 0 or LOW in this condition. Whereas, if there is no object in front of the IR sensor, the transmitted infrared waves from IR transmitter is not received by the IR receiver. And IR sensor gives 1 or HIGH in this condition.
Pin Configuration:

Pin Name Description
VCC Power Supply +5v
GND Power Supply Ground
OUTPUT Active High Output

The IR sensor module consists mainly of the IR Transmitter and Receiver, Opamp, Variable Resistor (Trimmer pot), output LED in details.

IR LED Transmitter:
IR LED emits light, in the range of Infrared frequency. IR light is invisible to us as its wavelength (700nm – 1mm) is much higher than the visible light range. IR LEDs have light emitting angle of approx. 20-60 degree and range of approx. few centimeters to several feets, it depends upon the type of IR transmitter and the manufacturer. Some transmitters have the range in kilometers. IR LED white or transparent in colour, so it can give out amount of maximum light.

Photodiode Receiver:
Photodiode acts as the IR receiver as its conducts when light falls on it. Photodiode is a semiconductor which has a P-N junction, operated in Reverse Bias, means it start conducting the current in reverse direction when Light falls on it, and the amount of current flow is proportional to the amount of Light. This property makes it useful for IR detection. Photodiode looks like a LED, with a black colour coating on its outer side, Black colour absorbs the highest amount of light.

LM358 Opamp:
LM358 is an Operational Amplifier (Op-Amp) is used as voltage comparator in the IR sensor. the comparator will compare the threshold voltage set using the preset (pin2) and the photodiode’s series resistor voltage (pin3).
Photodiode’s series resistor voltage drop > Threshold voltage = Opamp output is High
Photodiode’s series resistor voltage drop < Threshold voltage = Opamp output is Low
When Opamp’s output is high the LED at the Opamp output terminal turns ON (Indicating the detection of Object).
Variable Resistor
The variable resistor used here is a preset. It is used to calibrate the distance range at which object should be detected.

IR Sensor Module Features:
1. 5VDC Operating voltage
2. I/O pins are 5V and 3.3V compliant
3. Range: Up to 20cm
4. Adjustable Sensing range
5. Built-in Ambient Light Sensor
6. 20mA supply current
7. Mounting hole

1. Obstacle Detection
2. Industrial safety devices
3. Wheel encoder.

About the Author


Hello! My Dear Friends. I am Subramanian. I am writing posts on androiderode about Electronics testing and equipments.

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