I finally have peace of mind while traveling thanks to the door stop alarm. The post This Door Stop Alarm Gave Me Peace of ...

Dual Function: Can be used as a door stop alarm and door stopper, Its rubberized bottom prevents the door sliding and alert off intruders. Door stop alarms are available for door-to-floor ...

There’s a huge market for 433 MHz alarm system hardware out there, from PIR motion detectors to door and window sensors ... have it toggle a relay hooked up to a loud siren.