diy touchplate/ touchpad info plz

solusarpus · Joined: Nov 16, 2008 Posts: 4 Location: florida

hey guys, I'm looking for some info on touchpads/plates.
1. is there info on how to build an x/y/a touchpad, like the one in the moog voyager, that could be incorporated in a modular synth, or as a "skin" in a diy synthdrum?
2. similarly, are there schems/ infos for simmons or synare drum heads anywhere?
3. ditto for touchplates, ala buchla?

thanks a bunch, folks. -andrew

solusarpus · Joined: Nov 16, 2008 Posts: 4 Location: florida

oh, one more thing- is there anything like the voyage touchpad that can be bought as a module? thanks

metal_head_82 · Posted: Sun Apr 11, 2010 12:35 pm Post subject:

A simple touchplate could be made with a small piezo-cell mounted under a plastic plate or similar. When you hit the pad the piezo will send a small voltage which you could amplify and use as a trigger. This is pretty cool for drum triggers. But I'm not quite sure about that.

Another possibility is to use foil switches. they can be bought in electronic stores. Hope this helps a bit.

slugger · Posted: Sun Apr 11, 2010 1:26 pm Post subject:

not sure if this is at all in the realm of anything you're interested in, but I scavanged this from a little pocket LCD game thing:

Posted Image, might have been reduced in size. Click Image to view fullscreen.

Posted Image, might have been reduced in size. Click Image to view fullscreen.

It was originally being used as a switch (well, two actually)- a circular pad came down and pressed on the PCB, creating contact between the two interlocking sides. I'm using it as touch points for an Atari Punk Console oscillator. There is an APC mod which adds capacitors to make the pitch drop when switched into the circuit, I'm using this for the switches. It makes things a little more interesting as the contact isn't perfect.

[edit] To give an idea of scale, the screw on the left is the type often used on PC cases. The name of the game thing was "Pocket Game Player", seriously.[/edit]

[edit 2] Just realized these are probably the foil switches metal_head spoke of.[/edit]

metal_head_82 · Posted: Sun Apr 11, 2010 1:53 pm Post subject:

metal_head_82 · Posted: Tue Apr 13, 2010 1:23 pm Post subject:

Oh, by the way:

I found an interesting link:
http://www.toontrack.com/forum/tm.aspx?m=35166

It shows how to trigger an e-drum via a piezo. Perhaps one thing for your list?

fluxmonkey · Joined: Jun 24, 2005 Posts: 708 Location: cleve

serge's design: http://www.cyndustries.com/synapse/synapse.cfm?pc=39&folder=jan1977&pic=26

dugernaut · Joined: Jul 24, 2009 Posts: 50 Location: New Jersey

This might be helpful. I'd love to make one!

http://www.google.com/patents/about?id=Y905AAAAEBAJ

dshay · Joined: May 04, 2009 Posts: 18 Location: Minnesota

Sparkfun sells XY controllers, the below version is a 4 wire, which you'll need to follow a tutorial on how to implement because the outputs/inputs are shared and toggle between functions for when you're reading the x axis and then toggle to another function for when you're reading the y axis. A microcontroller does this so fast that it's no problem sharing I/O, it's standand procedure to share I/O for something they call multiplexing.

http://www.sparkfun.com/products/8977

http://www.sparkfun.com/products/9170

dugernaut · Joined: Jul 24, 2009 Posts: 50 Location: New Jersey

Cool. With a bit of extra circuitry and a couple more ports (and software), you could probably drive the +5 volt end with a constant current and pick off a high AND a low touch, or use it to pickup force (pressure) based on how much of your finger was on the pad. This was done in the early analog synth days for getting two notes out of a keyborad resistor string.