I have Simon XTi home alarm, with several PIR and door/window sensors. Suits my needs, almost.
While XTi does allow a NC alarm loop, there's no way to know which NC sensor, assuming more than one, is tripped.
For a sensor outdoors (PIR not recommended), I'd like to replace the reed switch of a door sensor with a relay closure, where the relay is activated by output of HC-SR04.
I don't want a microcontroller or c-code or computing, just a circuit that takes the output of the ultrasonic sensor and drives a NO relay to closed, in place of the door sensor's reed switch. A couple considerations are low-pass filtering to kill bounces, FPs, and some kind hold for up to 5 secs.
iow, an action just like the automatic door openers in, eg, grocery stores.
suggestions? circuits?
While XTi does allow a NC alarm loop, there's no way to know which NC sensor, assuming more than one, is tripped.
For a sensor outdoors (PIR not recommended), I'd like to replace the reed switch of a door sensor with a relay closure, where the relay is activated by output of HC-SR04.
I don't want a microcontroller or c-code or computing, just a circuit that takes the output of the ultrasonic sensor and drives a NO relay to closed, in place of the door sensor's reed switch. A couple considerations are low-pass filtering to kill bounces, FPs, and some kind hold for up to 5 secs.
iow, an action just like the automatic door openers in, eg, grocery stores.
suggestions? circuits?