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Button with analogue output?

Discussion in 'Sensors and Actuators' started by j4cobgarby, Dec 22, 2018.

  1. j4cobgarby

    j4cobgarby

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    Sep 18, 2018
    I'm planning on making some sort of synthesizer. Are there any buttons with a low activation force, and whose resistance varies based on how far down they're pressed?
     
  2. BobK

    BobK

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    That would be a pressure sensor.

    Bon
     
  3. VenomBallistics

    VenomBallistics

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    Aug 30, 2018
    If it were my show ... I think I'd opt for hall effect sensors in a sorta "roll your own" solution.
     
  4. Bluejets

    Bluejets

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    There used to be what was known as a "carbon stack" which was to control 220v to a series motor on a sewing machine.
    Other than that, I imagine a pot connected mechanically to a foot pedal would do what you want.
     
  5. hevans1944

    hevans1944 Hop - AC8NS

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    Well, of course there are! But here in the 21st Century you might have to custom manufacture your own. There was a (now expired) Kickstarter campaign to produce such buttons, but I can find no evidence that manufacturing actually occurred, beyond the delivery of a few prototypes to supporters of the campaign.

    However, "planning on making some sort of synthesizer" leaves a lot a room for hobby-type development and experimentation with different concepts. You should probably initially concentrate on producing a suitable actuator, a button with a limited travel that self-restores to its initial position when released. Think of a rod in a cylinder with a light-weight restoring spring in the bottom.

    Travel distance of the rod, and the force required to move it, will be determined by factors that you set. Once you have those details worked out, just add a sensor/transducer mechanism that translates rod position into an analog signal output. There are dozens (if not thousands) of ways to do this. @VenomBallistics suggested using Hall sensors. @BobK suggested using pressure sensors. I suggest that you investigate using a Texas Instruments invented chip that measures displacement inductively, by sensing the position of a small stationary coil of wire relative to a moving conductive surface, which could be the rod part of your push-button.

    The LDC1000 inductance-to-digital output is digital, but this digital signal can be easily converted to an analog signal with a digital-to-analog converter, available in low-end (inexpensive) PIC microprocessors from Micrologic. You would need one PIC per push-button, but they are quite small and could be integrated with the button and the LDC1000 chip. However, you might want to consider staying in the digital domain with your synthesizer... analog synths or sooo 20th Century. Also, consider using a COTS (Commercial Off-The-Shelf) MIDI (Musical Instrument Device Interface) keyboard to control the notes produced by your synth.

    You will need a computer and appropriate software to translate the MIDI keyboard signals into synth commands, but you can also purchase a COTS synth that will interface directly to the MIDI keyboard and NOT require a computer, making a kind of electric piano or organ or whatever instrument the synth is capable of reproducing. I did this late in the previous century, but I am no musician. The setup worked, but I was incapable to producing anything that sounded like music, at least to wife's ears (and maybe my children's ears too, but its hard to tell with teenagers). Your mileage (or kilometers) may vary.
     
    VenomBallistics likes this.
  6. JWHassler

    JWHassler

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    Dec 22, 2014
    You could try these not-cheap sensors
     
  7. VenomBallistics

    VenomBallistics

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    Now that you mention it. I did build a guitar MIDI interface from an issue of EPE .....
    It worked, but ultimately I broke down and went to vac tubes and built a trainwreck clone.
    Nothing beats honest organic noise boys
     
  8. hevans1944

    hevans1944 Hop - AC8NS

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    I LOVE vacuum tubes... my entire electronics career began (and ended) working with vacuum tubes. As for "honest organic noise," its really hard to beat the reality of quantum effects, such as the random arrival of electrons traversing "empty space" between electrodes in a vacuum. But what the heck is a "trainwreck clone?"
     
  9. VenomBallistics

    VenomBallistics

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    If you're not playing a tube fired guitar amp, you're not playing guitar
    The trainwreck is a Ken Fisher boutique design that leverages the compression region of its tubes. They all do this to some degree, but the wreck maximized the effect.
    You can gain stage it to ring sweet and clean with a light touch and as your pick attack increases, the over driven fangs start to come out. dig in harder and and it's the voice of classic rock. raise the gain and it'll give you blues to metal.
    In actual practice, it's on the edge of clairvoyance once you grow accustomed to its responsiveness. You feel it .. it'll preach it.
    While it's just a function of playing in the saturation segment of the curve, it's the closest thing to magic my rational mind will accept
     
    hevans1944 likes this.
  10. hevans1944

    hevans1944 Hop - AC8NS

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    "Any sufficiently advanced science is indistinguishable from magic." Arthur C. Clarke (b.16 December 1917 – d. 19 March 2008). Some folks who are into magic will say the converse is also true: "Any sufficiently advanced magic is indistinguishable from science," but let's not go there in this forum, lest we wind up in the Twilight Zone.
     
  11. VenomBallistics

    VenomBallistics

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    Aug 30, 2018
    That section has been my comic book section for a while.
    As long as tequilla isn't involved, and some known property of the universe can explain it, I'm not too worried about being a contributor
     
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