I have been working with the same basic approach to digital touch detection since the inception of the Keyglove. That process goes something like this:
- Pull all touch points to logic high
- Select possible combination [X, Y] from touch definition array
- Set point [X] low
- Measure the level of point [Y], and if it is low, then touch combination [X, Y] is active
- Increment test combination index and go back to step #2 until complete
At first, this method of scanning to detect connectivity between arbitrary I/O pins without mechanical switches seemed wonderfully functional and easily implemented. I used Arduino’s built-in digitalWrite() and digitalRead() functions, which was the simple solution. It was also plenty fast enough at the time. However, it has a couple of now-obvious shortcomings, plus another not-so-obvious one which I am hoping that I diagnosed correctly.
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