Infrared Sensor Ir Sensor Circuit Diagram. Here in this infrared sensor the lm358 ic is used as a comparator for comparing the sensor and reference voltage. The circuit diagram of the ir sensor using transistors namely obstacle detection using two transistors is shown below.
So when an object comes to the ir sensor the amount of ir rays from the ir transmitter falls on the ir receiver increases and therefore the voltage at the resistor increases. And non inverting end pin 3 is connected to the junction of photodiode and a resistor. Photo diode is connected in reverse bias inverting end of lm358 pin 2 is connected to the variable resistor to adjust the sensitivity of the sensor.
The ir circuit described below is mainly designed for liquid level detection or proximity detection.
The pir sensor typically operates at 5v so we are using a positive voltage regulator ic 7805 which will give 5v output to feed the sensor. So this circuit can be built with two transistors like npn and pnp. H ere is the circuit diagram of an infrared motion detector that can be used to sense intrusions. The ir sensors used here are an ir led and an ir photo diode.
