07-07-2014, 08:28 PM
(07-07-2014, 07:30 PM)cully Wrote: i did buy a 3 wire siren from evilbay but could not interface it, as the trigger wire was wrong, as it was looking for some sort of pulse to activate alarm,
i gave up with it and replaced it like for like
Yeh it's strange.. testing the leads, one is GND, one is +12V and the other pulses between +12-8V. I think it's pulsing all the time and I've tried putting a piezo buzzer between the fixed 12V and pulsing 12V, which works but then obviously then it's alarming all the time... So I don't know how the siren box is wired.. It's a mystery at the moment!
Have just fitted my re-built siren box but it hasn't worked.. I wonder if the internal batteries need a charge first though so will leave it overnight and test again tomorrow..