Make: Online : DIY capacitive touchpad

DIY capacitive touchpad

Flickr member svofski made this rather sweet touch-sensitive keypad with backlighting -

This a custom implementation of capacitive sensing technlogy as per QMatrix Whitepaper. It uses an ATmega8 to scan the keys and outputs ASCII characters to the serial port.

Schematic, PCB, and source code are available, though the project page is currently Russian-only. Check out the Googlish interpretation for details.

Update: As the pointed out in the comments, Google's Russian is a little rusty. For further explanation, best to check out the tech whitepaper.

Comments

Oldest comments listed first.

Posted by: svofski on March 25, 2009 at 7:33 AM

googlish

"Thus, a pipsqueak of crumbs on Ctank charge will gradually accumulate" :)

It's best to just refer to QMatrix Whitepaper, which gives a very good explanation of what's going on:
www.atmel.com/dyn/resources/prod_documents/qmatrix_white_paper_100.pdf

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Posted by: Collin Cunningham on March 25, 2009 at 8:02 AM

ha - good point!

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Posted by: svofski on March 25, 2009 at 11:26 AM

english description

Update: English description here:
http://www.sensi.org/~svo/capsensor/index.en.html

Reply to this comment

Posted by: jeff-o on March 25, 2009 at 11:44 AM

Looks like a next step for me!

I've managed to build a "keypad" with two buttons (see below for link), but this looks like a logical progression for my next project... or something like it! Hmmm, how can I put 12, 16, or more capacitive sensor keys to work? Oh, the possibilities!

http://www.instructables.com/id/Illuminated_Touchscreen_Poster_Frame_with_Sublimin/

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