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

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

Picture of 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

Picture of 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


eric gani (author)2017-07-09

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

ahmet_024102 (author)2017-06-29

distance how much meter axcept ? 2 meter ?

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

About This Instructable




Bio: I like making new things from trash. For more cool content please subscribe to my YouTube channel @
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