Touch capacitive sensors on AT42QT1070 fire constantly

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ntomkin
 
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Touch capacitive sensors on AT42QT1070 fire constantly

Post by ntomkin »

I have a large window display project, which worked well in our testing but now that its actually in place, I supposed the fields are building up in that space. Needless to say, I am desperate as this project was already promised. Now the sensors fire all the time for no reason. They don't even need to be hooked up. It seems any wire longer than 1 jumper wire causes complete havoc. I'm a little disappointed in this product, or my understanding of it.

Is there anything I can do to reduce field interference? I absolutely need to have a wire longer than a couple inches. This product is essentially useless if it cannot deal with longer wires.

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adafruit_support_mike
 
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Re: Touch capacitive sensors on AT42QT1070 fire constantly

Post by adafruit_support_mike »

Capacitive touch sensors detect changes in the picofarad range, so they don't have much room to be forgiving.

If it's at all possible, design the system so the control chip is close to the touch pad, then send the digital signals through the long wire. That's easy.

If there's no possible way to put the chip close to the contact, remember that capacitors are all about geometry. Make sure your touch pad has at least 10x as much surface area as the wire from the pad to the chip.

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