Hi Gang,
I have a auto cat feeder.. it has buttons on it's little circuit board - kind like those in a calculator (see image below). Those buttons have a kind of contact pad which pushes down on to them etc - how does that work..?
i.e. what are they sensing between the PCB contact patches - capacitance, resistance or..? I think if I just short circuit these they don't work (believe I have tried this in my long past)
Ultimately - I want to use a raspberry Pi to control the feeding timing (as the onboard controller sucks) - but I don't want to remove the controller.. just be able to use the rPi to effectively 'press' the manual feed button. I was thinking, I could just use a relay and have the rPi close that but I think the control circuit for these needs to see something else - as opposed to short circuit.
Please reply on topic - not looking for alternative ideas to the problem - just how these buttons work, hoping someone knows
thanks,
Ian
I have a auto cat feeder.. it has buttons on it's little circuit board - kind like those in a calculator (see image below). Those buttons have a kind of contact pad which pushes down on to them etc - how does that work..?
i.e. what are they sensing between the PCB contact patches - capacitance, resistance or..? I think if I just short circuit these they don't work (believe I have tried this in my long past)
Ultimately - I want to use a raspberry Pi to control the feeding timing (as the onboard controller sucks) - but I don't want to remove the controller.. just be able to use the rPi to effectively 'press' the manual feed button. I was thinking, I could just use a relay and have the rPi close that but I think the control circuit for these needs to see something else - as opposed to short circuit.
Please reply on topic - not looking for alternative ideas to the problem - just how these buttons work, hoping someone knows
thanks,
Ian