To which GPIO raspberry pi 2 should I connect the “button” contacts from the DoorHan gate control board?

Question

Raspberry Pi

I have a DoorHan sliding gate controlled by a PCB-SL v1.1 board and I have a raspberry pi 2. I want to open / close the gate through the raspberry. The PCB-SL v.1.1 board has contacts for connecting the open button.

I bought nano-switch wires in ampere, but I don’t understand which contacts on the raspberry to connect it to. I connected red to 3v3, blue to GPIO4, but the gate does not respond to commands from bash. There is probably something I don't know or don't understand.

Tell me how to do it right so that it works? Thank you.

Answer 1

If you do it strictly "in the mind":
1) find out how the open button is implemented. In 95% of cases, it pulls the controller input to ground.
2) Arrange optocoupler between PI and gate controller. So that no problems on the signal lines from the controller hang up PI
. As an optocoupler, a PC817 with a 310-470 ohm resistor connected to the GPIO
is suitable.