Body contacts to alter volume/distortion

[Dj Task Manager]

Hello there,
Im building a little stupid 1 octave mini-keyboard from 6 555's.
I had the idea of making a sort of fake pressure sensitive keyboard for it so when you press a key it closes the appropriate circuit but also on the part of the keys you touch there are body contacts which go to some sort of amp circuit to make it distort, so the harder you press (more skin in contact) the louder it gets.

I might try the circuit out of a walkman as i seem to remember they distort if you poke around on them with your fingers, but if anyone knows of an ultra simple amp circuit that distorts from body contacts that would be radical.

Fanx!

Task Manager

[Gordonjcp]

Body contacts work because your skin has a high but steady resistance.  You could devise a circuit that used a body contact across a resistor with a capacitor to smooth out the mains ripple coupled in from your body, that controlled a simple VCA or altered the biasing in an amp circuit.

[Dj Task Manager]

ok cool, i think i follow...
so maybe I could have a massively amped up signal leading back into the mix via a high value resistor (higher than skin provides) then in parallel to that i'd have my body contacts.
Sorry im pretty green when it comes to electronics, would this work?

[Dj Task Manager]

oh hang on that doesnt make sense does it the resistor wouldnt be doing anything in my circuit...
in that case i guess i dont get it!

[jamiewoody]

dj, i've been wanting to build a keyboard for a long time. i'm looking for inspiration, would you mind sharing a drawing of what you are doing?

i can't wait to try that mims mini-organ! i have other project loose ends to tie up first though...

body contacts rule! i built an APC that has 4 body contacts.depending on how it is set, you can play them almost like drum pads! who needs a KAOSS pad when you have something this cool?!!

[jamiewoody]

oh! i almost forgot, when i built that atari punk that i made the video of, i tried to add a body contact. because the box was metal (i think), the body contact could not work! in retrospect, i could have made a body contact modular with an rca cable or something. but, i think i have discovered i like plastic cases better than metal, for practical reasons!

[Dj Task Manager]

the keyboard im building is super simple and stupid.  It is literally 6 555 timers which pump out a square buzz in 12 preset notes.  So its polyphonic but you cant play every other adjecent semitone together; C and C# are run off the same 555, D and D# share a 555... and so on... I figured by paring up adjacent semitones i could half number of components i needed.  Im going to get that going then build some shit effects (body contact distortion, lfo, and maybe shonky spring reverb) to turn the buzz into a more organic, though still thoughly rotten noise.  Then build it all into a lovely box.  Thats the plan anyway!

[jamiewoody]

i was doing some breadboarding and i came up with a simple 555 vco synth, which is totally played by the HUMAN POTENTIOMETER! ;-) all body contacts, nothing else!