Connected my doorbells to Domoticz (relays + cheap remote)

[ThinkPad]

Been soldering this evening. Wanted to have my doorbells in Domoticz for a while....
Doorbells you say?? Yes, i have two because i live in an appartment (3rd floor). One down in the hall, and another one at the gallery (the actual frontdoor of my house).

The one that is connected to the hall is an intercom, a 'Golmar T-810'. I opened the intercom that hangs in my house and saw it has a buzzer inside. It spits out about 12VAC.
The normal doorbell is the same as in normal houses, a 8VAC transformer with a ringer connected

I searched for a while on the internet how to accomplish this and found some stuff about a KlikAanKlikUit doorbell sender and an optocoupler. But i didn't want to buy such an 'expensive' doorbell transmitter if i can buy a 433Mhz from eBay for $2
So i bought a cheap remote (SCT2260 chip, PT2262 clone) and fiddled around with some optocouplers, resistors and stuff. But i couldn't get it reliable enough.

I then tried a different approach, with a relay, diode and a capacitor. And that worked fine! I built it x2 and works great.
When one of the doorbells is activated a Pushover script is called so i get a pushnotification on my phone immediately. This is done by calling the script in the OnAction field (script:///home/pi/domoticz/scripts/doorbell.sh). For the PT2262 you also need to fill in a off-delay (i use 5sec), otherwise the switch will stay turned on.



I will draw the schematic later (Fritzing is very nice for that), but it is really simple:
Input: one of the wires goes directly to the coil of relay. Other wire goes to a diode (with the line marking at the relay side). Across the relay coil i have placed a small capacitor (100uF or so?) to stabilize the signal.
Output of the relay (NO, Normally Open) is connected to the button solderpads on the remote.

For the remote i would recommend a different one if you also want to build this. This one needed replacement of a resistor (3.3Mohm) before it was detected by Domoticz. There also exist cheap remotes that can be picked up directly by Domoticz i thought. Don't have a link/type however...

The next step is to send me a snapshot of ipcam. I only have to come up with a clever way to mount the cam so it doesn't draws attention. People walk by at the gallery and when i tried the cam was way too visible. But the script for it is already working.

[ThinkPad]

I just converted the setup to use the 12V adapter from my router, instead of the battery (type '23A') inside the remote.
Why use a battery if i have unlimited 12V available for 24/7 anyway.....

Attached a female DC-barrel connector to the remote, and just made this Y-splitter to grab power from my router:


I also see in my first post i promised to post the schematic, forgot that. Here it is:

The values of diode & capacitor aren't critical, just grab something you have lying around. Relay should be 12V DC, i also had it lying around.

[chokapick]

I was searching for a similar way to do this on google and found this page

You said the doorbell is powered by 12V AC but then you used a 12V DC relay.

Shouldn't the relay be AC to?

I also have a 12V AC doorbell and a spare Eurodomest waiting to be connect.
I'm still trying to decide how I will do it. I was thinking in a Optocoupler but a relay is also a possibility..

[ThinkPad]

The diode (marked 'D1' in the schematic) does a single rectifying step which makes the AC, DC
Optocoupler is also possible, but when i tried that, i had some difficulties in letting it work correctly. I read somewhere that it needs enough voltage to go 'fully open'.

A relay was easier for me. And also easier to troubleshoot, you can hear it do *click* when it is activated.

[chokapick]

I've also read that optocoupler needed more voltage... but they work on Arduino modules with just 5V so I don't get I people keep saying that (my knowledge on electronics is a bit limited as you already understand)!


I only have 30V relays at home but I'll get a 12V and try. I will let you know if it works.

Thanks

[Hesmink]

I want to build something like this, but preferably without the soldering bit.
I'm thinking of buying this: https://nl.aliexpress.com/item/Updated- ... 56199.html

My doorbell uses the standard 7.8V AC, and I'm thinking of changing that to 3V DC so I can use the ringer part of the Action wireless doorbell (by shorting the push button, and using the 3V to ring it.).
Found a similar solution on the internet, and except for the fact that people need to push the doorbell long enough, this is just a matter of connecting the correct wires.

Would this work?

[freijn]

Optocoupler is easy

This picture is for 5 volts and uses a 330 ohm resistor.
For 12 volts you can use a 1,2k ohm or something near that.

Connect the 'extern' terminals on the ringer device.
Forget if it is AC or DC It will work.

[niceandeasy]

I did something similar with ZWavePlus, the wall-mount 4-button control: ZME_WallC-S. It has 4 pushbuttons. Each of those 4 buttons can be used for some kind of a doorbell button.
My input stage is a relay. That's the easiest way to make it interface with the 8VAC or whatever your existing doorbell uses. And the NO relay contacts could just be connected to the existing pushbutton contacts of the ZME_WallC-S... But there's a problem. If pushed too short, nothing gets sent to domoticz. If pushed too long, nothing gets sent to domoticz.

Analyzing the two wires that I attached to one of the existing pushbuttons of the ZME_WallC-S: one is connected to ground, the other one is connected to the switch's internal chip or logic or whatever is in there, and, to a pull-up-resistor, as appeared when measuring on it with a multimeter.

For pushing too short: connect an electrolytic capacitor to the mentioned wires. The internal pull-up resistor will charge this. When the button is pushed very short, it will be discharged completely and after, it will charge. The time it takes for charging will keep the wire to the logic at a low voltage for just long enough to make it send a zwave signal.
Now for pushing too long: (use the relay or an extra switch for testing this). We will not switch the signal wire to the ground wire anymore. We'll create a virtual ground, using a discharged capacitor. So, when the button gets pushed, it will connect the signal wire to the capacitor. The pull-up resistor will charge that capacitor to the point that the logic will not register its voltage anymore as a low, as a buttonpush. Now, we need a high value resistor in parallel with that capacitor, to make sure it is discharged again when your next visitor pushes the doorbell button.
If your relay buzzes when supplied with 8VAC: add a diode and a capacitor, like Thinkpad did.
If you do Thinkpad's diode and capacitor, you could also do that circuit I proposed at the coil side of the relay, instead of at the ZMEWallC-S input. But you would need larger capacitors for that, since the relay's coil uses more power than the ZMEWallC-s input.

To build this:
Cut some plastic away from the ZMEWallC-S, to expose the pushbutton contacts.
Set a multimeter to low ohms. Put one lead on one of the contacts of one pushbutton. Put the other lead to another pushbutton's contact. Switch around your leads a bit, until you found which contacts of the 4 pushbuttons are all connected to eachother. That's your 'ground'. And the other wire will be your signal.
Solder at least one ground wire and at least one signal wire to your switch. Put the battery in, include it if not done so already and test if it still works.
Connect the signal wire and the ground wire to a breadboard.
Connect a 1uF electrolytic capacitor to those same contacts on the breadboard.
Connect a 10uF electrolytic capacitor and a 100K resistor both to ground and a free breadboard contact.
Connect a test pushbutton switch between this breadboard contact and to the signal wire contact.
Done. Now, go to your Domoticz log and abuse your pushbutton switch with short, medium-long, long and repetitive pushes and see what is appearing in your log. Feel free to vary the values of your capacitors and the resistor, until it exactly behaves as you want.
Mind the polarity of your electric capacitors. All negative polarities are connected to ground.
This is just 3 components. Feel free to use a PCB but I just soldered these components directly to my relay's switch terminals.
Now, test a bit more, by applying voltage to the relays coil terminals. After one last confirm that everything works as planned, put it into an enclosure and attach your relay's coil terminals to the wires that go to your doorbell ringer. If you want to silence that ringer, take it off.

Now, you can let Domoticz do whatever you want it to do when someone pushes your doorbell button, for example, ring your ZWAVE doorbell chime, but only at daytime, and turn on an indicator lamp, which can be turned off by one of those free buttons of your ZME-WallC-S, with another pushbutton near your frontdoor, take a picture to be sent to your smartphone, create a Do not Disturb switch, or whatever.
And the good part: if someone keeps on hitting that button frantically, the 10uF will not get time to get discharged, and your chime will only chime once.

EDIT: sorry for me being lazy and not including a schematic pic. would be better. now this full page of text could be much shorter if i did include a pic. meh.. too late for that, now. anyway, thanks for reading all the way to the end.

[Hesmink]

I want to build something like this, but preferably without the soldering bit.
I'm thinking of buying this: https://nl.aliexpress.com/item/Updated- ... 56199.html

My doorbell uses the standard 7.8V AC, and I'm thinking of changing that to 3V DC so I can use the ringer part of the Action wireless doorbell (by shorting the push button, and using the 3V to ring it.).
Found a similar solution on the internet, and except for the fact that people need to push the doorbell long enough, this is just a matter of connecting the correct wires.

Would this work?

Well, turns out this is not gonna work for me.
My 'doorbell' is an Urmet Arco 1715/1, with 1705/954 bracket. This means it uses Bibus 2/VOP.
The external doorbell button is connected to a switch in the handset, so I cannot just put something parallel over it.

Technically, I can connect wires to connect a second handset, so maybe I can somehow have a RPi act as a handset, or detect the signals somehow.
Found a wiring schema for the second set:

urmet arco.jpg (60.62 KiB) Viewed 4349 times

If anyone has any kind of experience with this, please tell.

[Hesmink]

To answer my own question: I mailed the Dutch Urmet importer, Elbo Technology BV, and they informed me I would need a backplate with a S+ and S- connector, but unfortunately I have an older backplate without those connections.