Passive MIDI foot switch

foot

[Matt] was looking into some software that allows him to use his audio card as a means to control analog audio devices. After seeing how it worked, he got an idea to try to do the opposite.  He is sending a signal into his audio input, and piping it to a pice of MIDI software. The input he has chose is a foot switch. To create the signal, he simply needed to supply voltage while the switch was depressed. You can see above that he used a battery and a simple contact switch to send the signal. He then piped it to a virtual MIDI port using Maple Virtual MIDI Cable. Unfortunately, this isn’t suitable for knobs, but that may be next on his list.

Comments

  1. hogiewan says:

    How is this passive?

  2. Abbott says:

    Hmm… that is a good question – passive usually means that a voltage isn’t sent from a device.

  3. Matt says:

    @hogiewan:

    Author here, I described the switch as “passive” because that’s how it started out and the hardware was pretty much trivial. But you’re right, I should have just described it as a “Simple MIDI footswitch” or something. Mea culpa.

  4. Jay says:

    I’m suprised there isn’t even a resistor in series…. Current limiting devices are your Friend!

  5. tony says:

    haha, right on jay. And always isolate mains power. You wouldn’t want to let the magic smoke out.

  6. lame hack says:

    Honestly this is a pretty lame hack. 2 x 16bit 44khz for a binary signal activated by his foot. That’s a lot of redundant data and processing. It would be easier to pull apart an old mouse or keyboard and use glovepie.

  7. SOOPERGOOMAN187 says:

    I’m at a total loss with midi. been trying to set up for glovepie and can’t figure it out. Maybe the OP would be willing to help. Then maybe I could build this also and put it to good use.

  8. fartface says:

    This would have been easier with the lpt port, yes your pc without one still has one, look for the header inside.

  9. Anonymous says:

    I’m quite a noob so I’m missing the point of this.
    what is this supposed to do? control some software application function via an analog switch connected to the midi port? emulate a keystroke?

  10. Liam says:

    @anonymous: you’re not the only one. So, what does it actually do?

  11. Brother_Maynard says:

    Orrr… You could just go the sysex route. Really not sure how this hack is totally useful. Although releasing a fake audio program with a fake soundbank and then having a website with a midi file that is linked to that app and let the drive-by malware begin. Anyhoo, keep plugging away.

  12. d clark says:

    I’m looking at the miduino card by tom scarff http://tomscarff.110mb.co/products_prices.htmmiduino
    to get input that can start/pause/continue a song using the song position indicator. we’ve bumped into a problem with not having an external clock in external sync mode. this sort of relates to the foot pedal. Any suggestions? I need to have a bunch of these up and running before halloween!

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