New doorbell

Electromechanical Relays
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1

I got a new 3 wire doorbell with no com terminal. My old doorbell had a com wire to make it four terminals. Do I just not wire the com terminal up and tape it off?

I’m doing this to connect a nest hello doorbell. Right now I have it direct conneccted witnojt the nest chime connetor to make the indoor chime work,but it buzzes. Unless someone knows how to get it to work without buzzing with a relay maybe. I don’t know how.

Thanks, Ryan

2

Hi Ryan,

Probably the com wire picks up noise as it is hanging. Try with connecting it to ground to see (or actually hear) if the buzzing sound goes away. As the com wire may carry two-way signal, the grounding can be safer to do via a resistor (10kOhm is an academic guess).

Cheers,
heke

3

Hi heke. What do you suggest grounding it to? Last night I lost camera signal like they said could happen without their google chime puck installed.

Thanks, Ryan

4

Hi Ryan,

OK, I pretty much assumed that this is an analog doorbell setup. No experience on the Nest Hello stuff.
Found this. May perhaps help.

Here the buzz is mentioned:
"without the chime connector, you might experience chime buzzing or unexpected chimes. "

Looks like you need a Google app to do the installation.

Sorry can’t give a better answer. Can you provide some pictures of your doorbell?

Cheers,
heke

5

Her are the best pics I can get

20210118_171211.jpg
20210118_171211.jpg3264×2448 870 KB

20210118_171344.jpg
20210118_171344.jpg3264×2448 1.15 MB

6

There are rumours of people using a transistor or a capacitor to get it to work properly without the chime but nobody has shared how to do it.

7

Apparently they used a relay

8

Hi Ryan,

Thanks for the pictures. They are actually very helpful.

It sounds like you cannot do that without the chime connector. If you connect the doorbell directly to the “1NOTE”, then the doorbell unit draws current through the chime solenoid and that makes it buzz. Is there a reason that you prefer not using the chime connector?

Now the key item is to determine, how the doorbell tells to the chime connector that it has to ring the chime. Probably there is a relay or something inside the chime connector and load modulator inside the doorbell to actuate the relay. It might worth testing with some relay how it works. Perhaps relay like
https://www.digikey.com/en/products/detail/nte-electronics-inc/R12-11A5-12/11643928
would work. You’ll need to connect the relay’s coil between the TRANS and doorbell and the normally open relay contacts between “1NOTE” and COMM.

If you have a current meter, you could perhaps measure the current draw of the doorbell (set the current meter to AC range, then connect one probe to “TRANS”, the other probe to doorbell (assumed here that doorbell’s other wire goes back to transformer). Then measure the current when the bell is not pressed and when it is pressed. The pressed time moment may actually be so short that the current meter does not detect that, but is at least worth trying.

Cheers,
heke