What's the best way for a Crackle Box-type circuit?

March 24, 2009 12:46 PM

What's the best way to make a Crackle Box-type circuit (where the user touches and closes the circuit with their fingers)?

I'm starting a project where I'd like to use a printed design as the basis for a Crackle Box-type interface...and I'm trying to find the best way to make the circuit.
The circuit is just going to act as a simple on/off trigger switch (into an Arduino or Make Controller Kit - just in case that effects the process.) FWIW, I have some basic electronics knowledge (ex. - I can muddle through circuit bending, hack little motors to run off batteries, and I've soldered a few small circuit board kits), so I'm using this project as an entrance to switch/trigger building. I'm about 75% sure I can get this switch cooperating w/ my controller board, but I'm soliciting advice on the making/printing of the actual circuit.

Initially, I was thinking of transferring the design via screen printing conductive ink onto a surface, but I'm having a bit of time finding screen printable conductive ink. I also don't know how conductive fingers are, so I'm not sure the right type of conductive material/ink to use. It will be battery-powered (a few double A's or a 9V), so there's no(?!) risk of inadvertently making a PainStation.

I'm also wondering about the material surface the design will be printed on, as I'm sure different surfaces affect the quality of a printed circuit. Would something w/ a high visual reflectivity (glass, polished stone, plexi, etc) hinder or dampen the circuit? This is also why I'm not going for the more traditional PCB-route; even if I did want to get into home-etched PCB's, I'm interested in more experimental/creative surfaces for the circuit to lie on.

Anyone have any suggestions? Thanks!

posted by itchi23 to technology (4 comments total)

I've used Quantum ICs like this for just what you're looking to do. Easy to incorporate into circuits, plus they work through thick dilectrics like plastics and glass, so no need for isolators or conductive ink.
posted by buzzv at 2:05 PM on March 24

^dielectrics
posted by buzzv at 2:09 PM on March 24

Depending on how elaborate (or not) you want the design to be you could use conductive copper tape.
posted by O9scar at 2:32 PM on March 24

thanks for mentioning those qIC's; I'm interested in using them in the future, but for the current project I'd like to have the actual exposed circuitry.

I will take a look @ conductive tape - thanks.
posted by itchi23 at 6:48 PM on March 24