Hi chaps, hope someone here can help me either design a unit or build one for me.
i have mains powered interlinked smoke detectors in my flat and an key fob operated access control unit on my front door that allows me quick entry in, rather than fiddling with keys. The front door is very strong and not easily forced open in the event of emergency.
What i want is to connect the 2 together in some way so that if there was a fire in my flat and i was unable to get out, the front door will unlock to allow someone in to rescue me.
the access unit operates a 'fail open' lock on the door, so all i need to do is interrupt this wire with a relay that would operate when the smoke alarm is sounding.
so... there are 2 ways i can see of doing this....1...use a sensor that will sense voltage or activity in the cable that interlinks the smoke alarms in the flat and operate a relay in the presence of that voltage.
2...use a sensor that will listen out for the sound of the alarm and operate the relay is its presence.
the relay will need to be held on for a period of time after the initial activation too. allowing access to the flat even if the smoke alarm stops sound ing, and have a reset button on the unit to return unit back to normal operation for use after false alarm i.e. burnt the toast!
Can anyone help me design this unit or better still build it for me?
I am obviously willing to pay!