Z-Wave mains powered smoke detectors?

[Alan Braggins]

The mains powered smoke detectors in my house need replacing.

At some future time I'm considering using Z-wave for some heating controls. Having mains powered Z-wave nodes to help with mesh connectivity seems like a good idea, and having alarms where one sensor can set off all the alarms also seems sensible (but not so worthwhile I'm keen to pull new signal wires through).

"You can connect the sensor to 12 or 24 VDC adapter if you wish" is going to look a mess, or involve making a large enough hole to tuck a socket and adapter inside the ceiling where now there is just a hole for a cable.

Mains powered alarms with radio interconnects that don't specify a standard and are presumably manufacturer specific are easy to find (and would be easier to set up the networking).

Other battery powered Z-Wave connected alarms exist.

But not, as far as I can find, the combination. Am I missing something?

And if I did switch to battery-only powered alarms, what's the best way to safely and neatly terminate the existing cable without enlarging holes more than necessary, and without sticking junctions boxes on the ceiling?

[Tim Watts]

Not ZWave but NEST do RF -> smartphone connected smoke alarms.

[Alan Braggins]

[...]

^mostly

[...]

True - I had counted it as manufacturer specific networking, but _possibly_ it would take part in a ZigBee mesh. And it's less than twice as expensive as the Fibaro, and nicer in some ways.

[Tim Watts]

You could use a 12V SELV lighting PSU, either remotely if you can get the cable to it, or cut a downlighter sized hole in the ceiling and push it up and through, covering the hole with the alarm?

[Alan Braggins]

Good idea. I'm so used to "mains to DC adaptor" meaning "wall-wart", I didn't think of that. And

says "In DC powering mode, configuration and association parameters are sent when necessary, and additionally the smoke sensor serves as a Z-Wave signal repeater." However it also says "It's not possible to power the device from a battery and VDC power source simultaneously. When using a VDC power source it's recommended to use another kind of power back up" which complicates things.

[Tim Watts]

One thing I just thought of: double check the 12V SELV pack offers clean smoothed DC.

I might have been talking bollocks as I checked and most don't specify DC output and some, even the electronic ones claim to be AC output.

The other thing to watch for is minimum loads as this alarm is going to present negligible loading - there are some SELV PSUs that expect minimum loads. Others don't care. Should be in the spec.

I would suggest bending your search towards 12V LED drivers - more likely to find a DC output.

eg maybe this:

It is 12v DC adn designed for lobbing into a ceiling void - it is not clear how clean the output is