Hello everyone! I am struggling the last two weeks with the intercom BPT E/220. Unfortunately everything I have tried where in vain. I am attaching a picture of the intercom and the cables connected to it.
What I know so far are the following:
- Intercom provides 11.5V DC between connections 2 - 1 and 2 - 3. There is not enough power to power up a shelly uni or even a sonoff 5V with step down.
- Door is unlocked if a connection with cable 1 and 2 is established
- When the door bell is pressed 1.2V is noticed between cables 1 - 4 and 3 - 4
I am able to power shelly uni with external power supply and unlock the door. But how would I be able to detect the 1.2V when the doorbell button is pressed?