Triggering a DSLR shutter with an audio clip

Apparently Pentax DSLR cameras have a remote shutter option that used infrared signals. [Pies for you] gathered up several different hacks and built a method of triggering the camera using custom audio. He put together the dongle above, just a headphone extension cord and two IR LEDs, which plugs into the headphone jack of any audio device like an iPod or an Android phone. When you play back a file the audio signals drive the IR LEDs. This is completely worthless unless you craft your own audio file using the correct frequency, duty cycle, and bit encoding. [Pies for you] did just that and got things up and running. Looks like the system doesn’t do so well with MP3 compression, but take a look at the waveform analysis that he posted and then make sure you’re using a lossless format.

Comments

  1. JC says:

    Nice hack. How about triggering it with an air freshener?

    http://jcopro.net/2011/02/02/remote-camera-trigger-using-an-air-freshener/

  2. Fooman says:

    Wow, ever since I’ve retired my trusty old T3 and replaced it with an Android phone, I’ve missed the Palm’s irda port for *exactly* this reason. I never thought of hacking the headphone jack for that. Sweet!

  3. bogdan says:

    That’s a really great idea. It actually works because there is a rather slow rise/fall time at 19Khz, so there is an off time between the polarity switching. The output capacitors and audio circuitry has something to do with this.
    It’s quite understandable why mp3 doesn’t work, but you don’t need that much wave time to make it work so not a big file considering modern day audio devices.
    I might make one too :)

  4. mark says:

    would it be possible to make one with a IR receiver and connect it to line in, then use it to record the IR output from a remote control, then use 1 like described up here to play it back?

  5. ejonesss says:

    you could just use the wav file it is full quality and lossless too

  6. Renee says:

    I’ve seen all sorts of variations on IR control and this is very interesting.

    What I don’t get though is that most cameras have a port to directly plug into for remote triggers. I don’t get why people just don’t wire up their own instead of doing this round about IR thing.

    I do know that some Cameras have proprietary plug types that would make it a pain but most seem to audio jacks.

  7. Alex says:

    @Renee

    I made this because my camera, the K-x, actually doesn’t have a proper “wired” trigger mechanism and relies soley on the IR port. It’s an unfortunate missing feature.

    However, one other advantage of this method is that it makes it incredibly easy for any device to control – for example I have now released an Android App which utilizes this method – check the forum thread for it if you like. This is the first time (I believe) any Pentax camera has been controllable through a smartphone.

    Also, about the .wav vs MP3 thing, of course it’s better to use the .wav but I investigated other formats because I’m aware that *some* MP3 players don’t support all formats. Also, when you start thinking about making many of these tracks for different situations, the size of the .wav files build up quite a lot :-)

  8. Hirudinea says:

    This is so simple but has so many possible uses, anything that uses IR could be under your control with nothing more than a cheap MP3 player and this thing.

  9. LOL says:

    on Pentax ? you can try Remotecontrol from SONY TV checkout TELETEXT button :)

  10. Alex says:

    @LOL

    Yes, and you can buy $3 remotes from ebay which do the job. The point is, with a .wav file its very easy for anyone, with very little soldering skill, to make a totally automated system for, say, astrophotography or timelapse.

  11. Stephanie says:

    Couldn’t you use this exact method to control any IR device? Say… A TV for example. Additionally, MIDI might be the best format for this. Or in devices that support it (anything programmible like an android phone), you could store the data as code instead of sound files. So instead of taking up memory or storage space, you have a program that outputs the “audio” on the fly based on a pattern you enter. All you would need is direct access to the audio output through software.

  12. echodelta says:

    Worth exploring for sure. Recording capture with a photo diode. A pod as TV-b-gone, emitters in earbuds or headphones. Big game coming up to use it on. Don’t Apples have wimped output though!
    High def 3D TV and multi-mega-pixel cameras but low-def audio. Any pod that can’t play wavs is good for a furniture leg shim. Kilobyte crap in a terabyte age, I just don’t get it. Don’t forget wavs are 1980 tech, it’s twenty eleven.

  13. Whatnot says:

    Now make one with IR sensors to record the original and complete the project eh.

    This isn’t new btw, in fact people have been releasing such ideas/prohects for decades

  14. daniel_reetz says:

    Alex, I can’t find your forum thread.

  15. Bob says:

    Lirc can do this too: http://www.lirc.org/html/audio.html
    I wrote the code for it in 2009, so I can say I thought of it first.

  16. Alex says:

    @Daniel_reetz

    Here it is http://www.pentaxforums.com/forums/pentax-dslr-discussion/131633-absurdly-simple-diy-k-x-remote-timer-using-mp3-player.html

    I’m not claiming this is a new idea. In fact the article clearly states I’ve pulled together several different hacks. This is just an implementation for Pentax camera users who are stuck without a wired remote port and with no cheap ways of doing IR remote timing. The cheapest commercial option that I have seen is ~£30. This cost ~£3 and is extremely flexible.

    Other options include wiring a cheap IR remote up to a wired remote timer, which is also quite cheap.

  17. Alex says:

    Also I’m not interested in ‘capturing’ IR signals because you only need one for Pentax. If you want to build one for other applications, feel free :). This project *is* complete as far as I’m concerned.

  18. Filespace says:

    any one notice this post on instr. is not asking to login to view anything?

  19. Hitek146 says:

    I first saw this hack a few years ago, being used as an IR transmitter for an iDevice, driving the LEDs through the audio out jack. The only was it could be made to work is by using two LEDs in parallel at opposite polarities. Since I wanted mine to fit inside the recessed jack of my iPhone 2G, I shaved off half of each LED(making a sort of “half LED”), and then glued the two “half” LEDs together, making “one” LED with two PN junctions of opposing polarity. Good times… :)

  20. Hitek146 says:

    *way

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