Changing a push button to a momentary electric switch

I have recently installed an interactive at Melbourne zoo, it basically uses an of the shelf intercom system, to communicate between to posts. Originally the activation switch was to be changed to an electronic momentary switch, however that didn’t work, as the intercom is a two button switch (one button activates a beep on the other speaker the other allows you to speak through the opposing speaker) the unit had to be installed with an emergency stop button, physically pressing the original button on the circuit board.
The emergency stop button lasted 2 weeks before it was snapped off.
I really need this to be an electronic activation rather than physical, can any body help? The unit is a ‘LEM1 1 call audio master aiphone, I have some images, if that helps
Original circuit and switch, intended switch and emergency stop button that had to be used.

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Hi Martin.
What firstly comes to mind is a capacitive touch type of thing but how to interface such a device into your present system I have no idea. Could be a bit difficult replicating a physical contact closure. Mounting such a device could present its own set of problems as well.
Sorry I can’t think of anything definite.
Cheers Bob

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Thanks Bob
Yes its a tricky one, as the switch seems to have 6 contacts on the circuit.

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Hi Martin
It just gets worse. Something would definitely need some sort of interface. 6 contacts suggests a 3 pole switch.
Cheers Bob

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Hi Martin,

Very sorry for the late reply.

@Robert93820 makes a good point about possible complications with it being 3 poles, before jumping into the rest of your restoration it would be good to probe each side of the PCB to see:

  • If the poles are shorted on the PCB
  • What kind of setup the switch has, SP3T, SPST, ect

If its a single pole single throw switch I’d have a look at using a breakout module such as this one: Standalone Toggle Capacitive Touch Sensor Breakout - AT42QT1012 | Adafruit ADA1375 | Core Electronics Australia
and a relay: Pololu Basic SPDT Relay Carrier with 12VDC Relay (Assembled) | POLOLU-2482 | Core Electronics Australia (depending on the current through and voltage across the switch you might be able to use a smaller relay or analog switch IC)

We’re keen to see how you go!