Door bell camera help

[Electro novice]

I have a Control4 home automation system currently in my house. The system uses a normal two contact doorbell switch normally open, push the button close the circuit type of switch. Two wires from the switch go to my AV room where I have a Control4 system processor that plays music throughout my house via in ceiling speakers. The two wires from the door bell switch connect to two ports in the processor one says 12V the other signal. When the door bell is pushed a chime is played through the speakers in the house.
Now I want to add one of the new Nest door bell cameras https://nest.com/doorbell/nest-hello/overview/ While still playing my door bell chime through the speakers. My problem is the Nest camera uses 16-24vac to operate and does not play nice with Control4. My thought is to use a door bell transformer to power the camera and then connect the wires from the Nest camera that would normally go to the chime to one side of a relay. the other side of the relay would have the 12v and signal wires to operate the Control4 chime. Doorbell button pushed closes the relay in turn closing the Control4 12v and signal wire side of the relay. Anybody have a better idea or if you think this will work a relay part number that would work for this kind of thing?

 

[dknguyen]

My thought is to use a door bell transformer to power the camera and then connect the wires from the Nest camera that would normally go to the chime to one side of a relay. the other side of the relay would have the 12v and signal wires to operate the Control4 chime. Doorbell button pushed closes the relay in turn closing the Control4 12v and signal wire side of the relay. Anybody have a better idea or if you think this will work a relay part number that would work for this kind of thing?

Your post is more vague than you might think. Give us more details on all the wires coming from the camera, including the number of wires. It's not as obvious from our side of the screen as you might think. You seem to assume that we just know what's coming out of it.

Also, you keep calling the doorbell a camera, and it took a few minutes of staring at the device on the website before I realized it was actually the doorbell itself and not just a camera that would be triggered by a separate doorbell. That's the kind of confusion that can occur if you're not specific or detailed enough.

Is the only difference between this doorbell-camera and regular doorbell that it has a second pair of wires coming out of it for an external power supply? What I am about to say below assumes this is true:

Take a look at a doorbell wiring diagram:
**broken link removed**

You can see that the doorbell itself isn't anything but a switch. It doesn't put out AC or DC. It just connects two electrical contacts together. If your doorbell-camera is the same way, then the doorbell-camera probably just closes a relay inside itself whenever it is pushed and you can just hook it up straight to your Control4's 12VDC and signal terminals. You can test by measuring the resistance between the two terminals when you push the doorbell. The resistance should go to zero when pushed. You can then verify by measuring the both the AC and DC voltage across these connections when pushed. It should stay zero in both cases.

 

[Electro novice]

Sorry for being vague. This photo shows the wiring for the camera/doorbell. The wires to the button/camera are at the bottom. Your guess is as good as mine what the round thing with Nest written on it is. Others have said the camera works fine without it. The camera is powered up all the time by the transformer I assume. I do not have one in hand yet.

 

[dknguyen]

I was editing my post while you responded. Please read it.

EDIT:
Useful for anyone else trying to help
https://nest.com/support/article/How-to-install-your-Nest-Hello-video-doorbell#install-nest-hello

 

[Electro novice]

No the round thing is not the Nest thermostat, maybe just a junction of some kind, not sure. There are only two wires to the camera/button then the two wires to the transformer

 

[Electro novice]

This is what the back of the button/camera looks like and how they have the transformer wired.

 

[dknguyen]

Okay. Two wires, huh? It must be stealing power from the regular doorbell circuit from the doorbell transformer while somehow being able to drive the chime when necessary. But yeah, I think your general idea will work (there seem to be extra crap that needs to be hooked to the nest which I can't guess at).

In other words, wire it up exactly as per Nest instructions exactly like you would a regular doorbell, transformer and all, except instead of wiring to a chime, wire to the coil of a relay. Then hook primary contacts of the relay to your Control4.
**broken link removed**

Basically replacing the chime with a relay in a regular doorbell circuit which should mean that you don't have to worry about what the nest is doing as long as you follow nest's instructions.

Most any relay should work. Just pick one where the control voltage (coil voltage) is the same as your doorbell transformer output voltage.

 

[Electro novice]

Perfect, thanks for your help!

 

[Electro novice]

Any guidance on where one might find a relay like that? Radio shack, amazon?

 

[dknguyen]

Oh, also, never run enough current to power something through the primary contacts of the relay you choose. Your Control4 is probably a "dry" signal (almost zero current). Running an real amount of current through it will produce corrosion on the contacts which will prevent the relay from reliably conducting lower currents at lower voltages in the future (not enough voltage or arcing to burn through the corrosion).

 

[dknguyen]

Any guidance on where one might find a relay like that? Radio shack, amazon?

Digikey or Mouser will give you the largest, easily searcheable selection tbh. Might be overkill for you though. However, I don't think a relay with 18-24VAC coil is very common though so you might need to go to them anyways. You want a single-pole, single throw (SPST), normally open, non-latching relay. Preferably a signal relay (I think, for your Control 4).

EDIT: Yes, it seems that 16-24VAC coil relays are not very common. In which case, you will be fine going with a relay that is more than SPST such as a DPST, or DPDT relay. You will just have more relay than you need and not wire up some connections.

https://www.digikey.ca/products/en/relays/power-relays-over-2-amps/188?k=relay&k=&pkeyword=relay&pv72=125&pv72=10&pv72=63&FV=ffe000bc,a8c0007&quantity=0&ColumnSort=0&page=1&pageSize=25

https://www.digikey.ca/products/en/relays/signal-relays-up-to-2-amps/189?k=relay&k=&pkeyword=relay&pv72=10&pv72=63&FV=ffe000bd,a8c0007&quantity=0&ColumnSort=0&page=1&pageSize=25

Some of them are kinda pricey to tbh. I would probably try my chances with a power relay due to cost and selection. Pick a lower primary contact current if you can.

 

[Electro novice]

Awesome thanks! you have been a big help.

 

[Electro novice]

Hey what about this idea. I buy a door bell kit from Home Depot **broken link removed** I can take the plunger out of the coil that strikes the bell and install a mini glass tube reed switch inside the coil. Attach my Control4 wires to either side of the reed switch. Ring the door bell, magnet engages and closes the NO reed switch closing the circuit to the Control4 door bell tone circuit. Thoughts?

 

[dknguyen]

As long as the reed relay closes, sure.