Hi. I installed a sonoff sv (after converting it into a dry switch) inside my intercom to be able to control the front door buzzer remotely. This works great with home assistant too, using IFTTT (hopefully I will manage to install tasmota on the sonoff one of these days, so I won’t need IFTTT anymore). Anyway, now I have a cool button on my dashboard and I can open the door of my building remotely… i.e. I don’t need to have the key with me anymore (I already installed a Sherlock on my apartment door, so no key for that one either)!
As you can see in the picture it fits well inside the intercom too, which makes it very neat! Except… that white cable you see going in there. That’s to bring 5V power to power up the sonoff sv. I was hoping that I would be able to find power inside the intercom but either there isn’t any or I’m doing something wrong.
I know this isn’t exactly a HA question, but I was hoping somebody might have an idea. This is the connection diagram (the 1st diagram in this link, type 8875). I used my multimeter and I can detect 5V voltage between some of the cables coming in the intercom. When I connect the sonoff to these cables though it doesn’t power up and when I put the multimeter again there, while the sonoff is connected, the voltage drops to 1V. Is there is a solution to this problem?
There is this solution called Nello and that one somehow gets power from the intercom and works, so i was hoping I could do the same. Nello also has a rechargable battery in it. Could this be how it works? Somehow the battery charges with low voltage and then is able to power up?