Infrared IR Sensor using LM324 IC

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Here is a simple project of an IR sensor using LM324 IC. The purpose of this circuit is to provide a visual indication by activating an LED whenever an object is placed in front of the IR LED and the photodiode. This circuit is really simple and is only using a few components like a battery, an IR LED, photodiode, LM324 op-amp IC, LED, and some discrete components. IR or infrared sensors are used in a lot of electronic devices nowadays like TV, DVDs, and many other appliances.

In a standard IR sensor circuit, there are three important components, an IR transmitting LED, a photodiode to receive the IR signal/light, and a signal amplification circuit. This circuit is also comprised of all these components to make it work. IR sensors have an infrared transmitter LED and a photodiode, the IR LED emits the IR signals continuously that are detected by the photodiode. The IR signal detection can be done by two procedures, one is directly or in front of each other and the second is by reflection.

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Hardware Components

The following components are required to make IR Sensor Circuit

S.no	Component	Value	Qty
1.	Input Supply DC	5-12V	1
2.	IR LED	–	1
3.	Photodiode	–	1
4.	IC	LM324	1
5.	LED	–	1
6.	Resistor	10KΩ, 470RΩ	1
7.	Variable resistor	20KΩ	1

LM324 Pinout

For a detailed description of pinout, dimension features, and specifications download the datasheet of 555 LM324

IR Sensor Circuit

Working Explanation

The operating voltage of this circuit is 5 to 12 volts. The working of this circuit is quite simple. We have to place the IR transmitter LED and the photodiode side by side (as shown in the circuit diagram). When an object or obstacle comes in between them the IR rays reflect through that obs\tacle and are received by the photodiode and it sends the signal to the op-amp IC LM324. LM324 is used for amplification and it receives the signal due to which its output pin 1 goes high and it activated the LED to give us a visual representation.