I don't know if this is the appropriate forum to post such a topic, but I just thought to try my luck anyway.
I have just bought a motion triggered PIR (Passive InfraRed sensor) alarm which basically triggers a built-in alarm. It features a kepad for arming and disarming the alarm, but my intention is to re-route its circuitry to trigger an external device bypassing its keypad arming / disarming circuits, to bring about the desired effect of triggering the external device when there is motion or body heat, and stops triggering when movements or source of body heat goes away - this will do away the need for me to disarm whatever it triggers via its keypad.
I know this sounds technically challenging, but if anyone can point the way to such guides and info, I'd very much appreciate it.