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CircuitPython Capacitive Touch Filtering
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CircuitPython Capacitive Touch Filtering

by paswani on Tue May 04, 2021 2:03 am

Hi All,

I'm a student working on a project using an Adafruit Circuit Playground Bluefruit, and I wanted to learn more about how CircuitPython's touch.io filters the capacitive touch data.

I've tried running simple capacitive tests in both CircuitPython and Arduino with similar sampling rates, and CircuitPython's touch.io was much more successful in holding a strong/consistent signal with less interferences and noise. I assume there's some filtering or something else going on under the hood and I'd be delighted to learn what exactly CircuitPython is doing in order to achieve the better signal.

Thank you!

paswani
 
Posts: 1
Joined: Tue May 04, 2021 1:50 am

Re: CircuitPython Capacitive Touch Filtering

by tannewt on Tue May 04, 2021 1:55 pm

We bitbang the touch implementation on nRF. The source is here: https://github.com/adafruit/circuitpyth ... /TouchIn.c Looks like we average 10 samples to get one reading.

tannewt
 
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Joined: Thu Oct 06, 2016 8:48 pm

Please be positive and constructive with your questions and comments.