LEGO Nikon IR Remote

Step 3 The program

Of course, as you might guess just shining an LED at your camera won't do the trick. Infrared remote signals consist of a number of blinks with defined lengths and intervals. But it gets even more complicated. The whole signal is modulated at 38kHz, which means that the beam is switched on and off 38 000 times per second. For this we will need a computer. More percisely, a microcomputer. I used a PIC because I'm familiar with programing one and I have a programmer for it. I already bought four 12F509 ICs for another project which I gave up on some time ago.

The following signal has been measured from an original Nikon ML-L3 remote:
2.0ms on
27.8ms off
0.5ms on
1.5ms off
0.5ms on
3.5ms off
0.5 ms on
repeated once more after a 63.0 ms pause

I got these values form www.alanmacek.com/nikon/

Using roughly these times I wrote a code that modulates the output at pin 5 of the PIC and drives the LED via a transistor. The supplied assembly code is meant to work with the 4MHz internal oscillator and must be modified for any other clock frequencies. The hex file is guaranteed to work only on a 12F509 chip.


This is not the place to go over programming a microcontroller and there are plenty of instructables out there for that. Just make sure that the thing works for you before you start soldering everything together, it will be hard to fix anything after. I just built the circuit on a breadboard and switched on my sister's camera's remote shutter mode.