I wanted to use it in our church to
monitor for fire and smoke. I used three
high-end Kidde dual-sensor smoke detectors
and three plain old X-10 door/window
modules. An NPN Switching transistor and a
9v relay, all of which fit neatly inside
the roomy housing of the smoke detectors,
and made for a perfect interface. The
Transistor takes the tiny current that runs
the piezo, and uses that to activate the
9volt relay. Once the relay responds in the
stead of the piezo, you can route it to the
pigtail of the X-10 Door/Window module. Just
for safety against false alarms resulting
from the chirp (which accompanies a low
smoke alarm battery), I put 10 year
lithiums in the smoke alarm and regular
alkalines in the door/window modules. This
way, the lithium always outlasts the
alkaline, and there can never be an
accidental trigger from a low-
battery "chirp" from the smoke alarm.
Yearly battery changes should keep this
system well in check. Now, you can buy one
of those smoke alarms with a DC light built
right in, but those models are only single-
sensor. They aren't good for sensing
ignition products like a dual sensor. They
would obviously be easier to fit with a
relay. I personally wanted to nix the built-
in piezo in the smoke alarms, because they
are mounted about 35 feet above the church
congregation. An accidental trigger from a
smoky candle or incense burner could set it
off, and I wouldn't want it to ruin the
whole church service. All in all, it really
would be easier of X-10 would just make this
unit for sale.
