Fire, Smoke & CO Detection And Alarming 31May21

I checked our Blodgett smoke detectors and they were all manufactured between 1994-1998. The sensors in these things last about 10 years so, yeah, they are way too old. I replaced all 10 @ ~$32 each with new Kidde units; they are all wired for 120vAC power and interconnected with a signal line so when one goes off, they all do. Of course the bezels needed to be changed too, as did the connector to attach to the detector - so complete swaps; I did reuse the wirenuts. One was actually faulty so I returned it and got a replacement the next day from AMZ.

I also wanted to have the smoke/CO detectors connect to my home IoT network so I can monitor in the SmartThings app. I first checked the ZWave compatible detectors available but they are more expensive and only battery powered. Another alternative is to install a "listening" ZWave sensor which will trigger if it "hears" the actual alarm sound... sounded hokey. Instead I used special relays tapped off of one of my new smoke detectors to capture smoke alerts and CO alerts - basically I'm using the signaling built into wired smoke detectors to capture any event throughout that network. The relays convert to signals that open/clove 120v which normally one can use to drive something else like sirens or lights. Instead I connected the relay output to some normal Ecolink ZWave window open/close sensors (because they have a binding block to accept an external open/close signal). Here are the relays ($15 each) and sensor hardware ($30 each).

I used a standard project box ($9) to house all the stuff and tacked it to the ceiling in a back bedroom with a smoke detector, off of which I could tap. I ran 3/14 Romex between the tapped smoke detector and the relays inside the project box.

The open/close sensors are battery powered so I need ongoing access to them to change batteries (or I need to add a 3.3v transformer to the install). The sensors are attached to the lid of the project box; I drilled holes through the top for wiring and used smaller gauge wires to tie into the external trigger interface block of the sensor (see small red and black wires attached to block).

I then wired the whole mess together tying the relays into the smoke alarm interconnect signal wire, and power, and relay outputs to the open/close sensors. Here it is before buttoned up - wiring is pretty straightforward with instructions included with the relays. I tested stuff before stuffing it all into the project box.

 

Once I had the ZWave open/close sensors joined to SmartThings, I associated custom device handlers (from vseven on SmartThings community) to them to get a more appropriate UI and alerting scheme (detected/clear vs window open/closed) within SmartThings. Done! Here's what the app looks like but I receive normal iOS alerts and can get email and/or SMS if desired. The CO detection and alert is similar.

I now get SmartThings alerts if Blodgett is on fire or experiencing a CO event. I needed this IoT connection in order to monitor smoke remotely the way I do for the garage doors, the spa temps, flood detection, intrusion detection, etc. since we split our time between Blodgett and the Nest.

UPDATE 11Jun21 - It Worked So Well I Automated The Nest Too... Cleaner Install