I am using arduino pro micro 5v 16Mhz. I have built a simple IR transmitter circuit as shown. Led is connected to pin 9 through 330ohm resistor

The code i am using is https://github.com/z3t0/Arduino-IRremote/blob/master/examples/IRsendDemo/IRsendDemo.ino

Although this worked yesterday, it doesn't seem to work now. I was able to turn on and off my TV yesterday but the led is not even blinking now. I checked led, its working.

After hours of trying to make it work I tried different library. https://github.com/cyborg5/IRLib2/blob/master/IRLib2/examples/send/send.ino

Surprisingly this seems to work but the code is a bit complicated for receiver.

I want to use the first library. Any help is appreciated. Thank you.

  • I'm not sure what help anyone can give you here. You had it working, presumably changed nothing, and now it doesn't -- how can we debug that?
    – Mark Smith
    Feb 15, 2017 at 15:40
  • It seems the library got the timer pins wrong I changed them and its working now. Feb 15, 2017 at 16:10
  • How did it ever work?
    – Mark Smith
    Feb 16, 2017 at 7:21
  • I used nrf24l01 module in between and maybe it changed timer settings. Feb 18, 2017 at 12:34

1 Answer 1


The problem was with timer timer settings in library. I checked different timer configurations with different pins and its working now. I found out that timer4 uses pin 13 which is not used in Pro Micro board so I am now using timer 3.

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