Thanks. Writing code is ok for me. I'll take a look at those sites
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 actually overseas at the moment so the unit is foreign but seems simple enough. Here is a photo of the box relay I can tap into.
Model of that is BC-200 (KCA) and the intercom terminal is a KCA HC-200
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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.
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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.
Thanks in advance for any help/suggestions!
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).
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And make sure you can remove everything quickly, not leaving any traces.
Agreed. That is definitely part of it 
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.
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Alright, found some weekend time and finished a big chunk of this project albeit ugly.
Found a way to open door without ringing my house from outside. There are three steps:
- Pick up phone (activate circuit)
- Press Monitor button (activates phone with outside system including audio and video in)
- press open door button. (Opens the door after step 1 and 2)
So since i had trouble finding zwave telays where i live i bought a three dry contact relays that use RF (i used broadlink rmpro to control them with Hubitat). Thr three dry contact relays successfully simulated the above steps through rule machine and a virtual switch.
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Thats the progress so far with some soldering and cleaning up. Next steps and issues:
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Replace RF wireless relays with zwave dry contact switch/relay because current ones do not have a status to HE which risks the fact that a button may be pressed and not unpressed with the relays i have.
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Still cannot detect if someone is calling me from building door or if security guard calls me (different tone audio and voltage on control line). For this I plan to use a potentiometer on thr control line to hook it up to an arduino or raspberry pi to detect the change in voltage and detect if someone or security guard desk is ringing the house. Not sure if thats the best idea but if anybody knows some good sketch for arduino or some python in rasoberry pi that can help me a bunch.
Update on #2. I may go the Voltage divider to Arduino with a cheap part like the below link. I should be able to tell the drop from 12V to 9V (if security) and to 6V (someone ringing outside) with this piece:
1Pce Voltage Detection Module Voltage Divider For Arduino With Data Line-in Integrated Circuits from Electronic Components & Supplies on Aliexpress.com | Alibaba Group -
Last is most difficult I think. I was hoping to use an old android phone to hook up to the intercom handset and use the android phone as a speakerphone when activated (simulated pick up handset). However finding cables or a device that can do that seems difficult. Most devices on the market are for connecting to your landline (not to the handset RF9 cable.). Also difficult to use headset jack on the android phone at the same time as using the speaker and microphone of the android phone. Hoping someone has a better idea for that part.
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Tapping into the coaxial video input to snap a shot when someone rings and send to my phone. No clue what to use yet.
Excuse the noobness on hacking an old device but it is a learning experience.
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Sounds like you have committed yourself to living there for a while. Thanks for the updates.
Lol, trying to keep it removable. If they like it they can use it. Otherwise easy to snip snip and back to original
