Smoke detectors, part 1
We moved into our house here in Seattle a bit over half a year ago. The house had been wired up with a security system and a set of interconnected, powered smoke detectors.We tested some of them and they seemed to work just fine even though the batteries weren't in them. (I know, not ideal, I should have put in batteries right away) The light on them was on like it should be and they beeped when you poked the button. No problem.Until one in the basement started chirping.No problem, maybe it was actually complaining about the batteries at long last. Insert 9V.And the chirps continued.Time for some research. Wired smoke detectors run off 120V (at least in the US) single-phase with a third wire that interconnects them. I didn't do a lot of research on how the interconnects work, but I'm guessing if you pull that line high (5VDC? 120VAC?) it should set off everything.So I pulled off the recalcitrant detector. The leads that were connected to it only read around 2.6VAC. Eh? I wound up leaving that one off, sitting on a shelf and not beeping.My guess about the 2.6V? That it's a phantom voltage because of running along-side hot wires. The coupling can cause a voltage on nearby lines like in a transformer. It wouldn't be able to drive anything though. If I had a low impedance voltmeter I would be able to verify this.
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A few weeks passed. I started thinking about how the detector was hooked up. Only two leads were connected. The third was dangling helplessly in the wire enclosure. As much as it was billed as interconnected, it really wasn't in this case.Oddly, there was another wire in the enclosure that wasn't connected to this detector.But this did get me thinking. If I'm sleeping upstairs, how the hell will I know if something starts beeping in the basement? I'm a heavy sleeper so this is a real concern.
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Enter Amazon. I don't just work there, I pay my own paycheck it seems. They had some wireless smoke detectors and I picked up a bunch of Kidde RF-SM-DC wireless interconnected smoke detectors
I have to say that I'm happy with how they wound up working. Obviously I didn't start a fire or anything, but they certainly seemed to talk to each other just fine. I was able to press one upstairs and I could hear them slowly percolate through the house in a few seconds freaking out the kitties in the process. Installation time: around 2-3 minutes per detector with a total of 7 installed.I'm also happy that the all the problems are solved (including a few that I hadn't thought of at first).First off, the smoke detectors were all working. Secondly, they were really interconnected instead of just purportedly interconnected. Lastly, in doing some reading, it seems that smoke detectors are recommended to be replaced every 10 years or so. The old ones were all vintage 2001, so they were likely due to be replaced anyway.I have to say that the Kidde Battery-Operated Wireless Interconnectable Smoke Alarms