Connecting smoke alarm to burglar alarm
 

My garage is separate from the house by about 20m. There is currently
a bit of a worry about security and I have rigged up a burglar alarm.

It then struck me that it would be a bonus if I could link a smoke
alarm into that too. Electronics is my training so I don't have any
problems in that area, but I've dismantled the smoke alarm (ie got it
out of the plastic !) and am puzzled to see that the piezo sounder has
3 leads - why ?.

The IC is under the sensor cover - would anyone know if that is likely
to have a dc output rather than the switching one for the sounder ?

Thanks
Rob

Connecting smoke alarm to burglar alarm
 

In article ,
robgraham writes:
My garage is separate from the house by about 20m. There is currently
a bit of a worry about security and I have rigged up a burglar alarm.

It then struck me that it would be a bonus if I could link a smoke
alarm into that too. Electronics is my training so I don't have any
problems in that area, but I've dismantled the smoke alarm (ie got it
out of the plastic !) and am puzzled to see that the piezo sounder has
3 leads - why ?.

The IC is under the sensor cover - would anyone know if that is likely
to have a dc output rather than the switching one for the sounder ?

Look at this thread:
http://groups.google.com/group/uk.d-...205e3d276d90f2

--
Andrew Gabriel
[email address is not usable -- followup in the newsgroup]

Connecting smoke alarm to burglar alarm
 

robgraham wrote:
My garage is separate from the house by about 20m. There is currently
a bit of a worry about security and I have rigged up a burglar alarm.

It then struck me that it would be a bonus if I could link a smoke
alarm into that too. Electronics is my training so I don't have any
problems in that area, but I've dismantled the smoke alarm (ie got it
out of the plastic !) and am puzzled to see that the piezo sounder has
3 leads - why ?.

The IC is under the sensor cover - would anyone know if that is likely
to have a dc output rather than the switching one for the sounder ?

Thanks
Rob

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

--
Toby... remove pants to reply

Connecting smoke alarm to burglar alarm
 

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

Connecting smoke alarm to burglar alarm
 

In article ,
Toby writes:
robgraham wrote:
My garage is separate from the house by about 20m. There is currently
a bit of a worry about security and I have rigged up a burglar alarm.

It then struck me that it would be a bonus if I could link a smoke
alarm into that too. Electronics is my training so I don't have any
problems in that area, but I've dismantled the smoke alarm (ie got it
out of the plastic !) and am puzzled to see that the piezo sounder has
3 leads - why ?.

The IC is under the sensor cover - would anyone know if that is likely
to have a dc output rather than the switching one for the sounder ?

Thanks
Rob

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

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.

--
Andrew Gabriel
[email address is not usable -- followup in the newsgroup]

Connecting smoke alarm to burglar alarm
 

On Nov 26, 3:43*pm, robgraham wrote:
My garage is separate from the house by about 20m. *There is currently
a bit of a worry about security and I have rigged up a burglar alarm.

It then struck me that it would be a bonus if I could link a smoke
alarm into that too. *Electronics is my training so I don't have any
problems in that area, but I've dismantled the smoke alarm (ie got it
out of the plastic !) and am puzzled to see that the piezo sounder has
3 leads - why ?.

The IC is under the sensor cover - would anyone know if that is likely
to have a dc output rather than the switching one for the sounder ?

Thanks
Rob

Just to keep this thread going ('bumping' I believe), the smoke alarm
in question is a cheapy from BnQ (~£6) 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

Connecting smoke alarm to burglar alarm
 

robgraham wrote:
On Nov 26, 3:43 pm, robgraham wrote:
My garage is separate from the house by about 20m. There is currently
a bit of a worry about security and I have rigged up a burglar alarm.

It then struck me that it would be a bonus if I could link a smoke
alarm into that too. Electronics is my training so I don't have any
problems in that area, but I've dismantled the smoke alarm (ie got it
out of the plastic !) and am puzzled to see that the piezo sounder
has 3 leads - why ?.

The IC is under the sensor cover - would anyone know if that is
likely to have a dc output rather than the switching one for the
sounder ?

Thanks
Rob

Just to keep this thread going ('bumping' I believe), the smoke alarm
in question is a cheapy from BnQ (~£6) 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?
--
Adam