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Electronics => Beginners => Topic started by: dteck on January 04, 2015, 10:28:25 am

Title: Capacitive touch over long wires?
Post by: dteck on January 04, 2015, 10:28:25 am
Hi everyone,
Right now I'm trying to play with an Atmel QT2120 capacitive touch controller in standalone mode.

What I'm curious about is how to manage "remote" electrodes. I want to have my electrodes fairly far away from the board. Maybe up to 12 Inches (30cm). Now the Atmel datasheet says to reduce stray capacitance around the pins. But with a long wire run I'm worried about them giving false detections. So I thought maybe something shielded like coax might be an option for running out to the electrode. But I imagine there will be some capacitance per distance in the coax itself between the conductor and the shield. but I don't know if it will be enough to be a problem.

I'm hoping someone with experience in touch sensing could share some insight on distancing the electrodes from the controllers. And maybe tell me if I'm worrying about nothing.