Hi all,

its been a while since I played with electronics, so could do with some
advice.

I have 2 magnetic door locks, keypad operated to control access into my
house. I also have a mains power smoke alarm system.

what I want to do is use a relay operated by the smoke alarm when sounding
to turn off the mag locks to allow people to leave with out having to get
their fobs out.

system was working fine with one mag lock, but now I have two I have a
problem. the smoke alarm when operating shorts out 2 wires going to the one
maglocks power supply. the electricians has simply connected those wires to
to the same connections in the new power supply. the problem is now that if
someone opens the back door with a fob, the front door also unlocks! and
vice versa. I was thinking about using diodes to try to get round this
problem. I'm not sure if I have explained the set up very well..so ask away
if you have any questions!

Cheers

Steve