How to Make IR Security Alarm & a IR Detector Using LM358




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In this project i will show you how to make a IR Security Alarm and a IR Detector with the same circuit, just with little modification. For the indication we have included both Buzzer & LED.


Step 1: Parts List

***Parts List***

1. LM358

2. 7805

3. 8 Pin IC Base

4. 2 Pin Terminal Block - 2 No's

5. Female Header

6. IR Rx

7. IR Tx

8. Resistor (39 Ohm, 10K & 470 Ohm)

9. Ceramic Capacitor - 0.1uF

10. 10k Pot

11. Buzzer

12. Red LED

***Affiliate Links or Purchasing Links***

1. LM358 -

2. 7805 -

3. 8 Pin IC Base -

4. IR Rx -

5. IR Tx -

6. Buzzer -

Amazon USA

1. LM358 -

2. 7805 -

3. 8 Pin IC Base -

4. IR Rx & TX -

5. Buzzer -

***Other Required Components***

a. Soldering Equipment -

b. PCB Board -

c. Wires -

d. Multi-meter -

Amazon USA

a. Soldering Equipment -

b. PCB Board -

c. Wires -

d. Multi-meter -

Step 2: Circuit Diagram

Construct the circuit as shown in the circuit diagram.


a. Alarm OFF state : When there is continuous IR signal transmitted from the Tx circuit there will be no Light & Buzzer Indication.

b. Alarm ON state: When there is an obstacle between the the Tx & the Rx circuit blocking the IR signal only then the buzzer & LED goes to ON state.

c. You can use the pot to set the range of the LED

Note : Please use the voltage range between 4.5 to 6 volt for better performance of the circuit.

***How to test***

After completion of the circuit, power the circuit with 9 Volt battery (Since we are using 7805) & let the IR Tx & IR Rx led face each other. When they are facing each other there should not be any LED or Buzzer Indication. Now introduce any obstacle between the IR Tx & IR Rx, When the obstacle is introduced there must be Light & Buzzer indication .


You can watch the test results in the video attached in the first page or CLICK HERE to watch it on YouTube

Step 3: IR Detector or Remote Tester

Now let us see how to modify the previous circuit to make it a IR Detector or Remote Tester.

You can also watch the video attached in this step or continue reading to know the odification

Step 4: Modified Circuit

***Tx Part***

The Tx Circuit remains the same.

Note: For this circuit you don't need a Tx circuit, You can use any kind of remote for testing

***Rx Part***

To modify the previous circuit to detect IR, you just need to interchange the connection of Pin 2 & Pin.

a. Connect the Pin 3 to the node where Anode of IR Rx & 10k meet

b. Connect the Pin 2 to the center terminal of the 10k pot

Rest of the circuit remains the same


To test the circuit simply power the circuit with 9v battery & press any button on your remote. When you press a button on your remote you will get both the LED & light indication.

You can also watch the video which includes testing. The video is attached in the previous step or you can also watch it on YouTube by CLICKING HERE



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    3 Discussions

    eric gani

    1 year ago

    how this things useful to me?how to use it`s properly?


    Reply 1 year ago

    when i tested the circuit the distance was around 8 Feet that's around 2.4 meter