Active IR DSLR Camera Remote for Android Smartphone

This is a set of instructions on how to build an active (externaly powered) Infrared remote for your DSLR camera or other IR device. You could use this device to control your TV or even as part of an intravalometer (time lapse) photography kit, the possibilities are endless!

The unit plugs into the audio jack of your smartphone which controls the unit by playing audio files of the correct frequency and pattern, i used 'DSLR remote' from the android market which worked well with my SONY NEX-5. Unlike other IR remotes this should work on any phone hardware, android, windows, Apple iOS even an MP3 player!

For this project you will need:
- 4 X 300Ohm resistors
- 2 X 13 Ohm resistors
- 2 X NPN transistor (BC547)
- 1 X PNP transistor (2N4126)
- 2 X IR LED (LD 274-3)
- AAA 2 cell battery holder
- 3.5mm audio jack

Step 1: Circuit

IR remotes are modulated at ~38kHz, so to start off we need to be able to produce a signal in this frequency range.
Unfortunately all audio amplifiers are only good for below 20kHz