I'm looking to include 50-100 capacitive-touch sensors in a project. I've found these SPI 12-key capacitive touch sensors. Would it be reasonable to use several of these for such a project, or is there a more natural solution?

I'm building a chessboard-like "grid" with 7x7-10x10 touchable squares, ca 3x3cm.

  • \$\begingroup\$ Can some cheap touchscreen for kiosks help? \$\endgroup\$ – zoonman Aug 6 '18 at 20:27
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    \$\begingroup\$ What sort of physical touch sensors do you have in mind? Glass screen? Metal contacts? Something else? \$\endgroup\$ – duskwuff Aug 6 '18 at 20:33
  • \$\begingroup\$ @duskwuff My primary plan is copper contacts under a PMMA sheet, so that I can light the surface up. \$\endgroup\$ – Anna Aug 6 '18 at 20:37
  • \$\begingroup\$ Not a full answer, but I wouldn't recommend any solution involving the MPR121. That part was discontinued by NXP in 2015 -- Adafruit is probably building boards with old stock. \$\endgroup\$ – duskwuff Aug 6 '18 at 20:44
  • \$\begingroup\$ Thank you @duskwuff , I didn't know. Is the disadvantage to using discontinued parts that it would be hard to order new ones? Anything else I'm not realising? \$\endgroup\$ – Anna Aug 6 '18 at 20:45

With that many active zones, you're going to want to think about matrix methods rather than completely individual electrodes. Here's a relevant application note from Freescale:

Designing Touch Sensing Electrodes


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