Connecting smoke alarm to burglar alarm

Look at this thread:

Another option would be to install a 12v detector like the Menvier m12.

Hi There are many smoke alarms out there (as posted) operating on 12v or you can buy a 240v unit with relay from most good diy outlets or if you are near an alarm supplier see if they do an adapter unit . As for the 3 wire to the piezo I can only think it is for the test button as some piezo sounders are dual voltage amd have 3 wires (com ,low,high). HTH CJ

but bear in mind that 12V buglar alarm smoke detectors don't have a sounder built in to them - they rely on the alarm to do that.

Just to keep this thread going ('bumping' I believe), the smoke alarm in question is a cheapy from BnQ (~=A36) called a Fire Angel. It dismantles quite easily though the labelling on the back needs to be ripped off, and the pc board comes out OK - I then desoldered the ionising device cover and found an IC in there which conveniently comes up on the web (RE46C122). Pin 2 of this is designed for triggering other alarms and goes high when the alarm goes off - isn't that convenient ! There is a track from this pin to the test/hush switch which will make a good output point.

I haven't tried it yet, but this gives me the 'in' that I wanted - assuming that there aren't variations on this IC that don't comply with the data sheet of course !!

Rob

Did you work out why there are 3 cables to the sounder?