Need help to make two doorbells work simultaneously.

[Anomajaya]

Hello everyone,



I'm not an expert on electronics. I have an old analogue doorbell that works directly on 230V AC. And there is another Wifi enabled smart video doorbell as well. The basic idea of my project is to make both doorbells ring when either button is pressed. As the video doorbell is very sophisticated for me to hack, I only could take out two wires from the momentary push button of that bell. Basically, I have extended that button and if I short those two wires together, the video doorbell rings. There is a 2.85v (DC) voltage in between both these wires.



I tried to synchronise both systems using two relay modules but failed. I’m attaching the wiring diagram herewith. Once I press the old system switch, it rings both systems. But, when I press the Video doorbell, it does not trigger the 3v relay module and hence the old electric doorbell. Once I press the video doorbell the indicator led in the 3v relay module lights faint and beyond that nothing happens. I know this is very primitive work and please bear with me as I’m no expert on this.



If any of you could help me in this regard, that would be highly appreciated.




Thanks heap.

 

[Bluejets]

Feeding voltage back in to your 18650 push button is not going to work and may in fact cause damage .

A simple relay off the 240v bell with a voltage free set of contacts to your 1860 push button would do one way switching there but the reverse, for switching the 240v bell off the 18650 system needs a pick up from that wireless wifi chime to a similar relay arrangement.

Biggest issue I can see here is the potential for getting yourself (or someone else) electrocuted from introducing mains voltage into the low voltage system.
Intentional or by accident, same outcome.
I'd suggest you forget it.

 

[bidrohini]

I think the problem you're having is that the 3V relay module is not getting enough voltage to trigger. The 2.85V signal from the video doorbell is not enough to overcome the coil resistance of the relay. You can use a step-up converter.

 

[Bluejets]

The 2.85V signal from the video doorbell is not enough to overcome the coil resistance of the relay.

The 2.8v is a part of a larger circuit and in itself, by applying the same/larger voltage simply will not work.
One would need the circuit of the former (which is likely never made available) to make any educated guess.
The issue really is the dangerous practice by those inexperienced to bring mains voltage and mix with low voltage circuits out in the real world.
A disaster just waiting to happen.