[sdiy] crackle box

[Ray Wilson]

OK It looks like the schematic uses the resistive/capacitive combination
that occurs when you bridge the circuit nodes with your fingers. All you
really need for the pads is some circuit board material or aluminum foil for
that matter. Of course soldering to aluminum foil is next to impossible so I
would use circuit board material. If you cut out little squares or etch
little squares from a larger piece and then solder wires to them (for
connection to the crackle-box circuitry) they will work fine. For just
goofing around with the circuit you could just touch the ends of the wires
connected to the circuit. I think that if you coat the touch pads with a
non-conductive material (polymer or adhesive tape) that the circuit may not
work because as I said before it looks like its the combination of
resistance and capacitance that gives the crackle box its interesting
operating mechanism. Be careful if you do connect the output to a mains
powered amplifier or you could get cooked (as in shocked).

Ray


-----Original Message-----
From: owner-synth-diy at dropmix.xs4all.nl
[mailto:owner-synth-diy at dropmix.xs4all.nl]On Behalf Of Caleb Johnston
Sent: Sunday, November 23, 2003 9:15 AM
To: synth-diy at dropmix.xs4all.nl
Subject: RE: [sdiy] crackle box



These touch pads will be similar to keys on a synthesizer.  The output would
be an analog signal from the finger tip.  Im not sure if the schematic is
designed for pressure sensitivity, heat or surface area of touch.  Here are
some links to explain the crackle box:

http://www.eam.se/kraakdoos/
http://www.xs4all.nl/~mwais/CrackleBox.htm

I am sure the people who designed these would know.  Does anyone have any
connections with them?

-C

>From: "Ray Wilson" <raywilson at comcast.net>
>To: "Caleb Johnston" <caleb_1 at msn.com>, <synth-diy at dropmix.xs4all.nl>
>Subject: RE: [sdiy] crackle box
>Date: Sun, 23 Nov 2003 07:56:21 -0700
>
>Hi Caleb
>
>I have not seen a "touch pad" per se but I am familiar with several
>mechanisms for creating a switch that will repond to being touched. Are
>these strike pads as used in electronic drums or are they being used in
>place of mechanical push buttons? What is the output you are trying to
>achieve? Switch closure? Logic signal? Analog signal which responds to the
>velocity of the touch? I imagine that if you provide more information
>regarding your application you will get more responses.
>
>Keep trying.
>
>Cheers
>
>P.S. I'm not familiar with a "crackle box" what is that?
>
>Ray
>
>-----Original Message-----
>From: owner-synth-diy at dropmix.xs4all.nl
>[mailto:owner-synth-diy at dropmix.xs4all.nl]On Behalf Of Caleb Johnston
>Sent: Sunday, November 23, 2003 6:55 AM
>To: synth-diy at dropmix.xs4all.nl
>Subject: [sdiy] crackle box
>
>
>I tried sending this question before, but it didnt get a response.  That
>seems odd, so maybe it didnt go through.  I am trying to build a crackle
>box.  The schematic calls for touch pads.  Anyone know where I can get
>these
>or a part number?  Any help on tracking down these touch pad components
>would be a great help.
>
>Thanks community synth brain
>
>-C
>
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