Create a LEGO IR Remote Transmitter with headphone jack for Sony NEX-5

Editor: Jim kajpust

I made an IR remote controller for NEX-5. Here is the picture:

IR transmitter in a LEGO brick

It’s actually a “sound wave to infrared signal converter“. Before using it to control the NEX-5, you’ll have to “record” the IR signal and convert it into a sound wave. For more information about the IR recording process, please read this blog: “World’s cheapest remote control replicator: just 1$ !’ by jumpjack“.

IR transmitter in a LEGO brick

I’ve already recorded the shutter release and the 2 second delay shutter release signal in WAV, AIFF and MP3 format (here is the zip compressed file). You can play back the sound file from any MP3 player, iPod/iPhone/iPad, Android phone, PSP,… to control your NEX-5.

Here is how the sound file looks like on the HTC Desire android phone:

use android phone to control Sony NEX-5

Of course, this “controller” can be used to control almost any IR device, as long as you have the proper IR signal in sound wave format.

The schematic of the IR transmitter with  headphone jack is pretty simple, you only need two IR LEDs ( I got those from old remote controllers), and one stereo audio plug or jack:

IR Transmitter schematic

By the way, there’s a problem with the IR port. If someone nearby is using a remote controller, your device might also react to the controller. That’s not good. Therefore, I think it’s better to make sure your controller is the only one that is commanding the device. My solution is simple: use a LEGO brick to cover the IR port, so it will not be interfered by other controllers.

Fortunately, the IR port on NEX-5 is just about the height of one LEGO brick:

IR transmitter holder construction

We can put the IR LEDs below one brick, that’s the exact location of the IR sensor.

Here are the parts I use:

IR transmitter parts

Here are the construction steps:

Solder the IR LEDs to audio jack:

Solder the IR LEDs to audio jack

The other side view:

Solder the IR LEDs to audio jack

Put them into one brick and stuff a small piece of eraser into the empty space behind the audio jack.

Put IR LED and audio jack into LEGO brick and stuff a small piece of eraser into the empty space

Finally, connect a stereo cable to the LEGO IR controller and MP3 player or a countdown timer application.

IR transmitter in action

Here is the rear view of the construction:

IR transmitter in action

I tried to connect the IR controller with a stereo Bluetooth headset to control NEX-5 wireless; however, it doesn’t work :-(

IR transmitter with bluetooth receiever

The ping pong ball diffuser is a replica of the idea from virodri in dpreview foruum, and it works great!

A simple Time-lapse solution and Long Exposure solution

If you want to take a series of time-lapse photos, such as taking photos every 5 seconds, you can use a Sound Editing tool, like the free and open source Audacity, to add 5 seconds of silence (no sound) at the end of the IR sound wave.

After that, use your MP3 device to loop-play the sound wave… tadaaa, you just made a time-lapse remote controller!

For a long exposure, just set the alarm clock sound effect of your iPod or mobile phone to the IR wave file.

And finally, I’ve made a EVILRemote controller for the Android phone (Android 2.2 and above is required) which has to use with is IR device. The app is free and open source and you can compile the source code into iPhone / iPod touch app.

Have fun!