I am in a pickle and want to know if you can help me. I have an IR sensor and receiver and want a program that makes a light bulb flash or detect whenever the IR receiver is in range. So whenever the IR sender detects the receiver, it should print "detect". This will be done using the Arduino program. And it is an Arduino Nano I am using.

These are the things I use:



How should this program look like? Anyone have the code for this?

Never mind the LED blinking, I just want the program to know whenever the receiver is detected and probably display it somehow. My plan is to send the number of times the transmitter detects the receiver to an Android app in the end.


2 Answers 2


You can't.

IR is a one-way protocol. The transmitter has no way of knowing whether a receiver is in range; it's literally just an LED that emits infrared instead of visible light.


Assuming you got receiver and transmitter mixed up, then its simple. Otherwise, its not as simple. As @duskwuff points out, simple IR is one-way. The Transmitter here is just an IR Led. That's it. The Receiver is a Remote Control type IR Receiver, looks for a 38khz modulated IR signal, and removes the 38khz carrier wave, passing on the data to be read by the other end.

For a IR beacon type setup, in either simple or two way mode, you'd need two micro controllers.


  • Microcontroller A is the Transmitter. All it does is repeatedly send out an IR modulated code. The Arduino IRLib library can do this.

  • Microcontroller B is the Receiver. It looks for that specific code, and if found, does X, which could be print to serial, or send over bluetooth to a phone.

Complex, both receive and send:

  • Microcontroller A is the main part. It sends a code then switches to receive mode for X seconds. If it receives a confirmation or its own code back, it tells the phone/pc it has been found or flashes a different LED.

  • Microcontroller B is a beacon/repeater. It waits to receive the code above, then switches to transmit mode, and sends the same code or a different code back. That's all it does. A Basic IR Remote Control Repeater.

This tutorial at Adafruit explains it all, with code examples.

  • Yes, How would I do this? I have 2 arduino nanos. How would I program the 1 to be a receiver and the other 1 to be a transmitter? Is there code anywhere of someone that did this? I have an IR emitter and receiver. Should I use 1 emitter on the 1 arduino and 1 receiver on the other?
    – Face
    Jul 28, 2016 at 8:07

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