Dear vseven,
Thank you for this post. It’s very helpful and I plan to connect my Kidde smoke and CO detector to Smartthings. Bear with me, I am not great in these electrical stuff so I would like to ask you if I can connect both smoke and CO relays to a single smoke/CO combo detector (KN-COSM-IBACA). I assume that CO and smoke signals use the same red interconnect wire and the relays will filter the respective signal (smoke or CO)? Is that correct?
Also, I want to use the DC 9V (grey wire), what the other wire is for DC out?
Thank you. TD
Yes you can connect both relays in. The interconnect/signal wire carries both the smoke and the CO signal and the relays go off when they see the signal they are looking for. I have a combination of smoke and smoke/CO sensors all with the common signal wire and the relays work fine.
As for the 9V DC you cannot use this as a general power source. Its used for pull stations (those “Pull For Fire” things on the wall) and gives those the power they need. Then when someone pulls one it sends the signal on the signal wire. That is also why its only on the smoke relay.
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This is great. Thank you very much. TD
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I wired ecolink window sensor normally open to the Kidde 120x relay. It works. However, the battery only lasts a week. The only thing I think might be causing this is the cover doesn’t close super tight and often see that the cover open in recent activity. Any thoughts? I might just tape the tamper switch and put in a new battery.
I had that happen on one of my Ecolink sensors. The cover latch was broken on the white cover so I swapped it out for the supplied brown cover. If the tamper switch is activated by the cover being loose it will always report open and will drain the battery really fast.
BTW I have the Kidde relay setup and it works great with the hardwired combination smoke and CO detectors I am using. Even with replacing the detectors with brand new units (mine were very old and expired) this setup was 1/2 the cost of using the Nest or similar “smart” detectors.
Cheers.
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If your ecolinks (or similar) are up in the attic and your running off of battery (which in itself will decrease battery life):
- solder a small jumper across the tamper switch (SW3) so the tamper switch is electrically removed.
- Would recommend cutting one leg of the reed sensor (SW1) on either side and insulating so they don’t touch each other or elsewhere. Unlikely, but you have no control over electronic fields or even charged magnets nearby (example: transformer for a special light fixture near by). The use of this device assumes that the reed switch NEVER activates. I’ve seen reeds also fail closed. The result is that your alarm would no longer trigger.
- Might want to cut an LED leg at the same time to further reduce battery drain.
- Consider wiring in an exposed simple SPST toggle into the battery ground path if your ecolinks are tucked away since inclusion\exclusion only requires the battery.
Could provide pics if needed.
If your going to be wiring a high voltage box with low voltage divider anyway, you can get a slightly larger gang and wire in a simple 4 lead AC to DC power supply that accepts your input AC voltage and outputs 3.3VDC. Look for one with wire-in leads if using wire nuts. Use a reputable safety tested brand. Recom Power like this for example. Ecolink doesn’t have a typical\worst power spec that I could fine but everything on Digikey for example was at least 1W which is more than enough to handle a couple if your doing CO/smoke. The more Watts, the bigger it will probably be. The 3.3V (versus 3.0V and below) may result in some RF improvements. Don’t believe there are step-up regulators for the battery so your always going to use only part of the capacity and as the voltage decreases, that usually translates to some side effects. Downside with an AC powered sensor is that it’s gone when the power goes out.
Anyone ever get false alarms from their install of this? Just curious if it’s something simple I could address.
I installed this all shortly after @vseven posted about it and supplied his DTH so it’s been more or less running fine for a couple years now. I’ve had to replace the batteries in my 2 Ecolink’s once in that time, nothing crazy.
Ever since i installed it though, I’ll get a single false positive smoke alert every few months. Not enough to spend a bunch of time looking into the why, but enough to remember, and maybe not trust it when it pops up on my phone and no one is home. I just assume it was a false alarm.
Obviously this kind of defeats the purpose, but curious what others have ran into. Could it be a bad Ecolink? Bad Relay? I know it isn’t a bad battery and they alert SmartThings correctly when tested. It doesn’t reset either, I have to go bring a magnet to the Ecolink to get it to reset. Maybe this is my answer? 
Magnets… could that be why by smoke detector shows “smoke”?
Are you using the external contacts, did you solder to the reed switch or did you remove the reed switch?
I’m just wired up to the contacts.
One works 100% as expected, the other one just has an occasional false positive.
If I had to guess it’s a false positive from your Reed switch. @beedix a few posts above had some good suggestions on modifying the ecolink to make sure its own sensor won’t trip and only the externals will be used. Cutting the Reed is the easiest of his suggestions (number 2 in his list).
I had two false positive from the same sensor in about 6 months time and none from the other. I never bothered hunting it down and I’ve since wired mine directly into a Konnected board simply because I had two open inputs and it was 10 feet away. Only regret with this is now the are “cloud” based. I’ve been debating switching back so they run locally. Also been debating using a SmartSense water sensor, one of the new style ones with the exposed prongs on top and bottom, since you can get those pretty cheap.
Positive it’s not anything in the DTH, nothing was modified in the actual logic. Really just a capability change and some different labels.
I removed my reed switch when I used the sensor with my wink system so I would say cut one end of the reed switch or mount the magnet next to it.
I’ll try mounting the magnet there first. Thanks for the idea. Want to avoid cutting if possible.
If your modifying, you don’t want to cut just one end of the reed switch. This seems to leave the comparator or other logic in a state that prevents proper bootup. What you need to do is cut both ends to fully remove the reed switch. Then you need to solder a small wire from the now empty reed switch hole (the one closest to the battery) and solder the other end of the wire to ground. The other end of the now missing read is not modified.
You can mount a magnet, but keep in mind the description of occasional state changes mentioned could actually be a defective reed that can fail due to the mechanical nature. If your not afraid of a quick solder, I’d go that route if you want to be sure.
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Mine’s been running fine for several years. That being said, I’ve observed a number of false positives from SmartThings over several years on two hubs.
This solution is a bit easier with no mods or relays and does work with the talking Kidde smoke/co interconnected units.
…Just posting a note on the Ecolink Firefighter with Kidde Talking Smoke and CO detectors. We recently replaced four direct wire, interconnected alarms with the Kidde ( Model 900-0119 ) which give you three chirps followed by a voice warning of “Fire” or four longer chirps followed by a voice warning “Carbon Monoxide”. These smoke/CO detectors are direct wire, interconnected and have a front loading battery backup system using two AA cells.
Out of the box, and using the custom handler, the Ecolink detected nothing when testing the alarms. I called Ecolink and they were unable to assist, although I am waiting for a call back. The tech fellow I was talking with informed me that the Ecolink Firefighter listens for at least three cycles of the “Temporal 3” Smoke Alarm ( 3 short chirps + pause) or three cycles of the “Temporal 4” CO alarm (4 long chirps + pause) alarms. There is apparently a standard that UL approved smoke and CO detectors should be adhering to.
I did get the unit working by changing modes as described below. I removed it from SmartThings and rejoined to the hub after doing the following:
C0 Alarm Detection
In addition to Smoke Alarm detection, the device can detect the presence of a carbon monoxide alarm. By default, the
sensor is not guaranteed to detect a CO alarm. The device can be configured to more reliably detect a CO alarm in
exchange for a reduced battery life. This mode can be changed by holding down the tamper switch and learn button for
10 seconds. The device should then be reset ( remove battery and replace ) in order to determine the current device
setting.
RED + GREEN = Device will not reliably detect CO, but standard battery life
RED + RED + GREEN = Device will more reliably detect CO, but with reduced battery life.
Btw, when you pull the cover, note that the tamper switch is not the learn button. The printed documentation unfortunately does not make that clear:
SmartThings can be then set up via Smart Home Monitor to report smoke alarms. It won’t trigger on CO alarms, however WEBCORE works fine for that.
Hope that helps!
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Hey Allan, Is there an updated Device handler that works with the new SmartThings app? wondering if you or anyone has tried to get it to work?
Thanks
Derek
Just to confirm I am following this write-up… it appears you have separate Smoke and CO detectors correct? If I have a setup where I have the combo CO/Smoke detectors, can I just use one relay and it will alert for either Smoke or CO?
Yes, that is exactly how I have mine set up.
No that’s not correct. Smoke and CO use different signals in the interconnect wire. I have 3 smoke/CO combos and 5 smokes and bought the two relays and hooked them both up to the interconnect wire so they detect when any of the detectors alert. See post 3 for my similar write up.