Triggering a capacitive sensor

Jimmy W.

I am working on a project where I need to trigger a capacitive sensor on another device, I only have 1 and I am not willing to destroy it! I have tried what a few other people have suggested with just feeding it vdd through a 10k resistor and no dice, I was pretty sure that's all it would take but there is not much data out there about fooling capacitive sensors, just on using them or interfacing them.

Any ideas guys?

Jimmy

Leon

What sensor?

Leon

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Tubular

If its a touch style sensor - or a capacitive prox sensor - you should just need a similar dielectric. Water has a high dielectric constant and saltwater even higher.

It possibly works using a tuned AC excitation - feeding it DC would not work in this case but you won't have done any damage with a 10kohm series resistor. To see if its AC you could attach a CRO probe to a coin size bit of metal, go near the sensor and see what you pick up.

Some of them work by having a free-running oscillator which changes frequency due to the change in partial capacitance introduced by the sensed object.

As Leon suggests we need more info about the sensor if possible

tubular

Jimmy W.

That is part of why my hunt is so fruitless the only information I have on the sensor is as follows Touch style sensor with "single-ended capacitance input".

Thanks for the suggestions, its hard when you are guessing blindly!

This is for an AMX piece and sadly they wont give me any info, only that "any attempts to bypass the necessary interaction of a human being to the button(sensor) is most likely to fail", encouraging words!



Jimmy