I am trying to develop a way to electronically simulate an object moving relative to a capacitive proximity sensor, a way to change the capacitance of a small (1 square inch) electrode under logic (TTL) control. The sensor would detect the change in capacitance and trigger, without anything actually moving mechanically. The response time needs to be on the order of 10 ms. The obvious solution would be to have a switch that would ground or float the 'stimulus' electrode, but it needs to be a very low capacitance switch to make the 'delta C' as large as possible.
Any ideas?
Any ideas?