Home Automation

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Is there a way to wire a relay for doorbell #1, relay for #2, and outdoor switch for both? (lemmy.world)

submitted 1 day ago by pageflight to c/homeautomation

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My house was previously multiple units, and has nice sounding chime doorbell for two floors. I've set up a relay board so family members can ring one or the other bell from HomeAssistant. If someone comes to the front door, I'd like them to press a button to ring both.

Obviously I can use a smart button and a simple automation to trigger two relays. But is there some way I'm overlooking to have a dumb, standard wired doorbell button that will ring both chimes without causing either relay to also ring both?

Maybe there's a DPST weatherproof push button out there that would look nice on the wall?

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[–] [email protected] 5 points 1 day ago* (last edited 1 day ago) (1 children)

It's easy even without a DPST switch if the relays are SPDT (and many are)... Basically now the relays switch between nothing (upper contact, if present) and ON (lower contact). Make them switch between MANUAL and ON:

[–] pageflight 2 points 1 day ago

Oh nice, yes the relays are dual throw and I had forgotten to consider that!

[–] [email protected] 3 points 1 day ago* (last edited 1 day ago) (2 children)

/edit; ah shit...AC. Not DC.

For AC: use a single-throw dual-pole switch (a switch/button that closes two seprate circuits with one action). (S2 in this diagram)

For DC: You can use two diodes.

Switch1 triggers Coil1, S2 triggers C2, S3 triggers both.

I used coils for traditional bell relays, but any load will do.

[–] pageflight 1 points 1 day ago

Fun to see the DC solution though, thanks.

[–] [email protected] 1 points 1 day ago

The relay coils are operated with DC so you can implement the bottom diagram but for the relay circuit, not the bell circuit. Just add diodes between the MCU's GPIO and relays too, they are probably driven HIGH/LOW and not HIGH/High-Z.

[–] NateNate60 1 points 1 day ago

Switch C is a button that completes two separate circuits without connecting them. You can buy this part online. Big home improvement stores probably also stock it depending on where in the world you live.

[–] NeoNachtwaechter 1 points 1 day ago (1 children)

The "dumb" but reliable way would be to install 2 wires from your outdoor button to the trigger side of both relays. There are mechanical buttons that can close 2 circuits at once (I don't know the proper English term).

[–] [email protected] 1 points 1 day ago

DPST (double-pole, single-throw)

[–] [email protected] -1 points 1 day ago (2 children)

[–] [email protected] 2 points 1 day ago

You might need a beefier transformer but what do I know?

[–] [email protected] 1 points 1 day ago (1 children)

Read the post

[–] [email protected] -1 points 1 day ago

No.