Friday, August 5, 2011

Using stereo 3.5mm jack to communicate with IR remote

I was thinking about making a universal 3.5mm jack device (IR and more).

This is not a new idea, versions of it has been around for 7 years, but it is still a cool project.

Griffin had something like that patented for several years, read this article, it is still cool. RedEye Mini has recently covered it commercially. Total Control seems to have Android version.
    For IR remote, the first approach is to communicate to 3.5mm jack, it seems that you can pre-record messages as 36kHz - 44kHz, 16bit Stereo square PCM (pulse-code modulation) wave files. Here is a geeky in-depth article from

    RedMote is providing Android source code and apk as well as few sample WAV files. The design is very cool:

    Here are the components needed as provided by RedMote: (Former Bender) is providing great schematics for the project:

    Quoting from the article: "two IR LEDs mounted in reverse [..] each IR LED will emit half the signal/frequency (15~20Khz). Together they will reproduce the original IR frequency exactly like the original remote."

    The optimal solution of course it to develop a sound generator and plug in the remote specifications.
    Here is a listing of remote specifications.

    I also think it would be cool to design Arduino board/shield that would plug in to 3.5mm jack and be able to receive:
    • IR emitter for controlling AV equipment (and add some social sharing component to TV watching)
    • IR proximity sensor to trigger stuff like alarm, or camera/voice recording
    • Ultrasound Sonar for various distance detection
    • and more..

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