Since I live in the city mid-rise, I do not have the option to install the new fancy intercoms out there so I have to deal with what the building has (or until they upgrade it).
I was wondering if anybody is familiar with the wiring/signals and if there was any way to tap into them to signal Hubitat when someone rings from outside or to open the door.
Note: I have access to the relay box and basically there are four wires on both sides: Ground/Power/Ctrl/Audio. On the bottom of the relay box there are video cables from what I'm guessing is the outside camera, security guys camera input.
The intercom system is very old but basically someone punches in a code outside and it rings my place with an annoying sound on the terminal. I pick up the phone (yes that old) and video and audio show up. I assume the Ctrl has a signal going through when that happens?
The relay box runs at 15V DC (has a transformer next to it). I'm guessing I might have to go an Arduino or Raspi route? Or anybody know an easier product I can get to just signal me when someone rings from outside the building? Or if Arduino/Rasp, any similar type project? (Again, large building with many tenants so I cannot put my private wireless button out there).
Yes, that was one old thought I had but it's near the living room and if I'm watching a movie I'm worried it will keep triggering randomly.
I even taped an old Android phone and used light sensitivity so when the video comes on it triggers. That worked for the alert part but the cat found away to kill that and it was a pain to get the Android updated so I took that off.
Hoping I can tap into the relay cables somehow which might even give Hubitat a chance to buzz someone in too. Maybe I need to trace the signals that go through?
You might want to try one of the DIY sites to see what might have been done and what you could adapt to your system. https://www.instructables.com/howto/intercom/ https://hackaday.com/?s=intercom
There are likely other sites but I am familiar with these two.
You would likely need to write some code to do any integration with HE but????
Back at my old apartment, I had a 14.5~15v DC relay to open the doors, and a buzzer built into the intercom as an alert.
I was able to use a dry contact relay to open/close the door circuit as a momentary button, and then use an energy meter to determine when the speaker was on (it went from 0 to 13v when it was on).
I can't remember exactly what products I used, but it was all z-waved based.
Do you have a model number of your Intercom? Perhaps pictures of the inside/outside of it?
I'm guessing I can connect the video and ground to an RCA/Composite cable and hook that up through a AV2USB dongle to a Raspberry PI to capture analog video. That way when the video starts showing up then that means someone is ringing outside the building. I could even add the audio/ground to that too.
If don't see any better way, going to try that and see what happens. Then the Ctrl to open the door which will require some more learning on my side.
would love to have it like those videos of people who live in flats and enter morse code with their buzzer for different audio responses and unlocking the outside door to the building. Those were entertaining but not my primary goal.
You could try a SPDT relay that is hooked up to a contact sensor with external terminals (or I soldered my wires to the board). You can read about my project here:
Basically I have a USB brick plugged into an outlet that provides 5V output to a relay. When power is cut the relay changes state NO vs NC and the contact sensor detects that and via HE can perform an automated action. Thinking you can buy a 15VDC relay and do something similar.
Nello. They have a wifi based product.
I'm looking for the same solution as you but it has to be zigbee baded.
If you find something interesting, I'm open for suggestions.
I use a Speakercraft LL One to detect audio coming from the TTS on an android device to trigger the PA switch on my whole house audio system for announcements. It works super slick.
Maybe you could tie the audio feed into this. The output is a 12v trigger, so you could run that into a relay or something. There are other audio triggered relays out there that don't have the 12v output and are just a relay. Run one of those into a zigbee or zwave contact switch.
Another option might be a Pi Zero W. Run the audio into a couple of pins and monitor for voltage on them, when voltage is detected from the audio, send a REST API call to Hubitat to trigger something. Microcenter has Pi Zero W's for $5 (limit of 1). You could use an ESP8266 also, but they have less capability and cost more than $5. With both of these, you can easily connect a relay to them to trigger the front door lock.
Working on the project now that I got some pieces. Got a AV2USB for a Raspberry PI 3b and hooked up a DVD with composite analog video and audio out. Looks like it works when capturing through the built in VLC on Raspian. Would anybody know what's a good next step to find raspberry pi software (or a template I can feed off of) to trigger hubitat (through Maker or HTTP) when audio or video starts pouring in? (i.e. when someone rings my house through the outside, video and an audio beeping start). Even better if there is something to send an image to my phone or stream :). I noticed the video signal from the relay box uses coaxial which I can convert to work with this.
(Still a noob with the raspberry but ok to do programming).
I haven't got to the door electronic strike or whatever it's doing yet.
Just wondering what you are doing to isolate what you are doing from the apartment system? It would be sad to have something you are doing fry the system.
currently testing outside the actual system. Going to run power separately from the system and measuring the different lines (with a multimeter). Don't think attaching a video and audio out from the system will hurt the raspberry pi input but worse case my raspberry pi will fry.
Good point though, that is on the back of my mind before i start attaching wires.
there's also a switch on the box relay to turn it off when I do it (you might see it in that photo above).
Finally got someone to help me measure a few things. The cntrl signal is 12V but drops to 6.45V when someone rings my flat. It briefly (1 sec) drops to 3.12 then back to 6.45 if I push open door button. Audio also has activity. Found the video signal to my flat as well fourth from left. Don't think a relay will help with the cntrl signal
Finally broke open the in-house intercom unit (has a TFT screen and phone and door button). couple of other buttons for security office.
Here's a few pics of that. Found the embedded relay. Will add a z-wave relay to short the 12V control line just as the button does.
Going to intercept the coxial video and split that and put a coax to AV to USB into a Raspberry Pi.
Audio still not sure yet. Activating unit will require some kind of way to drop the 12V to 6.15ishV which would be the hardest part. Going to leave that last.
