555 timer Capacitive sensor switch
Search for circuit
A simple 555 timer Capacitive sensor switch can be designed using this circuit diagram. In this circuit, rectangular wave is integrated by triple RC network, while IC2, used as a comparator (with a baseline variable), use the integrated voltage changes to connect and disconnect AC relay. To decrease the risk of incorrect switching, with P1 and P2 is made fine and gross adjustment.
By changing the existing frequency signal, the integrated average value remains the same, but when the frequency is changed, there will be a positive or negative peak voltage due to momentary change in the average waveform signal.