A curfew security system with a Raspberry Pi Web Server and Particle Photon nodes. Used in Carnegie Mellon Pittsburgh Summer Pre-College program for underage students.
Each Particle Photon “node” uses an algorithmic mutex lock and a reed switch to update the Pi Web Server once when a door is opened (reed switch loses contact to magnet).
The Pi, hosting an authenticated web server, serves a web page for monitoring all devices (doors) and to curfew timings. When alerted, the Pi alerts the hosted web page, texts guardians via a GSM module, and raises an alarm.