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Help Needed - Cap Touch

A project log for Periodic Table of Motion

An open platform for creating installations to show various types of motion. Useful for museums and schools. Composed of individual cells.

Bob BaddeleyBob Baddeley 11/05/2015 at 02:421 Comment

I thought I had learned my lesson with the first museum exhibit I developed; don't use buttons because people, especially children, are brutal. So I moved to capacitive touch buttons. And I thought that would solve the problem. A single sheet of acrylic in front of each column of elements would be easy to clean, would provide a nice interface, and wouldn't have any mechanical problems. Well, it does all those things, but presented me with a billion other problems.

I need help figuring out how to get the cap touch to work for the elements. Here's how it's configured now:

This works. Usually. It worked in testing just fine. However, when I installed everything at the museum, things went crazy. Here are some of the problems:

I spent a lot of time playing around with different sensitivity values for this, but I'm worried that it doesn't matter because each element seems to behave differently. I'd really like a consistent configuration because putting them in and taking them out of the installation is difficult, so tweaking each element would be horrible.

Discussions

Mike Turvey wrote 10/31/2016 at 18:54 point

This comment may be far too late to help, but something I've considered for a touchless sensor in the past has been an IR distance sensor.  If the acrylic isn't too opaque or foggy in the IR spectrum, it might be a more reliable choice.  (i.e. something like: https://www.sparkfun.com/products/242).  Instead of instructions to "touch the button..." you'd have to say something like "wave your hand here..."

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