Connected Smoke Alarms

My weekend project was to integrate my hardwired, inter-connected smoke alarms with Smart Things.

I used a post from the Vera forums as a guide

My alarms are made by Kiddie, so I got the appropriate relay for my system (Kiddie SM120x) and the Schlage RS100HC door sensor. I paired the Schlage sensor with the ST hub and it was recognized right away, although I did have to log into the web I.D.E. and change the device type to “Schlage Contact Sensor” to get it report properly. I saved the magnet for the sensor for future projects because it is not needed.

I have access to one of the Smoke Alarms in my basement, so I mounted another electrical box about a foot away and ran 14-3 wiring. I hooked the black (line), white (neutral), red (inter-connect) of the relay to the new wire I ran from the existing smoke alarm. I then hooked the blue (common contact) and yellow (normally closed contact) from the relay to the small terminal screws inside the Schlage sensor (I capped off the other relay wires). I drilled a hole through the side of the plastic case on the Schlage to allow the wires to connect with the cover on. It was tight fit but I got it all into the electrical box (I think I am going to shorten the wires some more on the relay to free up some space).

Now on Smart Things the sensor shows closed until the smoke alarms are activated and then changes to open. I have set-up “Notify Me When” to send an alert that the smoke alarms are active. I also set-up “Turn it on when it Opens” to turn on all of the lights in the house when the alarms go off (should help us get out at night). It has all tested out and works great! Now if I could change the icons from open/closed to something smoke alarm appropriate, it would be perfect.

Kiddie has a separate relay for CO2 alarms so I may do a similar set-up for CO2 detection.


Thanks for this info @trotsky40

I’d thought at times about what benefit a “smart”-smoke detector would bring and you showed some good examples here. I like the ‘notify’ option and I think the this would be a good use for the siren as well.

Love the idea of turning on all the lights in the house! Even turning on outside lights would be a great idea too… make it easier to see after you get out as well as making it easier for Trucks to find your house.

Another great use would be to notify if the battery level was running low.

Does anyone know if a z-wave smoke detector exists? I see that 2Gig makes a smart smoke detector, but I don’t think it uses z-wave.

One thing to add:

Now if I could change the icons from open/closed to something smoke alarm appropriate, it would be perfect.

Presumably you could create your own device type. You should be able to just copy the existing Schlage open/close sensor code for your new type and then just make some minor changes. Here’s part of the device type code:

	tiles {
		standardTile("contact", "", width: 2, height: 2) {
			state "open", label: '${name}', icon: "", backgroundColor: "#ffa81e"
			state "closed", label: '${name}', icon: "", backgroundColor: "#79b821"

I wonder if just changing the “state” labels from open or closed to “no Smoke” or “FIRE!” would work? Guess I don’t know if that’s a label or a if open closed is specific code.

Also in there is the call for which icon. You’d probably have to ask ST what icons are available though.

This is exactly what I’ve been wanting to do, but I didnt think about taking apart a door/window sensor to connect the relay to. I’ve just ordered the relay for my smoke detector (USI-960), and I already have a few spare Schlage door sensors…will be wiring this up this weekend!

I created a new ‘smoke alarm’ device type, and copied the Schlage open/close sensor as you suggested, changing the code to the following:

tiles {
		standardTile("contact", "", width: 2, height: 2) {
			state "open", label: 'FIRE', icon: "st.alarm.alarm.alarm", backgroundColor: "#cc0000"
			state "closed", label: 'NO SMOKE', icon: "st.alarm.alarm.alarm", backgroundColor: "#0000FF"

Seems to work good, I reused the Smart Things alarm icon, and changed the labels to FIRE and NO SMOKE - Also the background colors are blue and red.

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Ryan that sounds awesome. Is there a mechanism for you to publish the device type (I looked and didn’t see it in the device list)?

No, it only lets me publish it to myself. You can create it pretty easily though through the Smarthings API. Just click on My Device Types from your device list, then +NewSmartDevice, then give it a name, select Contact Sensor (I also chose battery), keep defaults and then Create Device. Once you do that, in the upper right corner there’s Device Type examples, pull that down to Z-Wave Schlage contact sensor. You can then choose to “Overwrite”. Once overwritten, copy/paste the tiles section I put above, and you’re in business. Once it’s saved and Published, you can then choose it to assign to your smoke detector Schlage sensor.

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I emailed support and asked for a complete list of icons for device types. We’ll see if they get back to me.

A z-wave dry contact relay/switch wired in series with a group of smoke/fire sensors works fine.

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Do you have a link to that post on the Vera forum that you used?


I tried posting it my original post but it didn’t show up. (Edit: Tried again and didn’t work. Link function must not work):,15334.msg116522.html#msg116522


I got this from support:

I think you might use st.particulate.particulate.particulate for when smoke is detected. :slight_smile:

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Thanks for the walkthrough instructions! That was way easier than I thought it would be. I am very comfortable on the hardware/wiring side but have no experience on the software/coding side.


That is a great link. I went ahead and changed the icon for “Fire” to the particulate and I changed the “No Smoke” to st.Home.home2 (a nice little house).

I want to test it this weekend and make sure everything is fine with the new device type (no reason it shouldn’t be). For some reason, my wife doesn’t like it when I test the smoke alarms in the middle of the night :slight_smile:

@trotsky40 do you know if the smoke alarms start chirping for low battery, does it activate the relay and then the ST sensor? I’d hate to be out of the house, get notifications that the house is on fire, call 911 and have the fire dept show up just to change the batteries out :slight_smile:

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@ryanwebb I haven’t had a battery go dead yet (relativley new system) but the manual doesn’t indicate that the it will set off a general alarm through the inter-connection.

The more I thought about it, the more I am sure it won’t. The chirp is to allow you to identify which alarm needs a new battery. If all of the alarms start going off, you won’t be able to identify which one needs the battery.

Seems that this has not been updated in several months. How many individuals have this running now, and was anything else learned?

I haven’t had any issues since I set mine up in August. I have periodically tested and everything was fine. We did have a phantom alarm at midnight a month or two back and the system worked exactly as designed. The smoke alarms sounded and all of the lights in the house came on. My wife was able to get our 1 year old son quickly and I was able to check the house for fire. Luckily, it was a false alarm but the system worked well.

My only wish would be that the Schlage sensor reported battery level. I periodically have to check to make sure it is still reporting in to the Smart Things hub.

Thank you Blake & chrisb! I just used your instructions to connect my hard wired BRK/First Alert smoke&CO2 alarms. I used the Schlage RS100HC door sensor, wired to the BRK RM4 relay. Wiring was super easy. I put it all in a box from homedepot that I placed next to one of the smoke/CO2 alarms. I set up a new device type and used the default zwave door sensor code and made the changes suggested by chrisb. Now I receive a message and all the lights in the house go on as soon as there is a smoke/CO2 alarm!
I have not done much coding in groovy yet so it would take me quite some time to figure this out: Is there a way to change the status message on the Dashboard? I got it so say “OK” when the sensor is closed but have not been able to chnge the “open” message to “ALARM”. any ideas?

@pizzinini What I have found is, it is not the device or “thing” you really want to change for external reports. What you want to change is the SmartAPP. This is true for reports for push notifications and E-Mails and not in the “things” status page of the phone app. If the SmartApp believes your “thing” is XXXX then it will report it as XXXX no matter how you have it configured.

I purchased a bunch of water sensors from lowes (really cheap) and during my trial and error of getting them to report something other than the “XXXX” is “wet”, I found that changing the “thing” in the IDE only created more complications. I found the SmartApp the “thing” is associated with is what actually reports the phrase and not the “thing” iteself. By changing the SmartApp report to say what I wanted I gained the desired phrase and status. Now I can make them report that XXXX is open, arrived, departed, closed, hot, cold etc…

For instance, my driveway alarm used to say “Driveway alarm is ‘wet’”. Now, it reports “Driveway alarm is ‘active’”. I did this by going into the SmartApp and changing status from “wet” to “active”. Everything else stays the same.

I hope that this helps. If not let me know.

Thank you for the suggestion, makes sense and keeps things clean!

I have set up my rules (e.g. alert message, all lights on) through the dashboard right now instead of creating a Smartapp. Does the dashboard create code that I can then just copy to create a new Smartapp (and then modify with your suggestions)? Or do I have to code the app myself (maybe leveraging piece of other existing Smartapps)? Sorry, just getting started with this… Thank you!