In brief: control hub + autonomous wireless sensors · 180° detection · anti-tamper · fingerprint reader · battery tracking · 3D-printed enclosures
When wild camping, an animal or a person can approach the campsite during the night. I wanted a compact, lightweight and self-contained system to secure a zone around the camp, without relying on a phone or any external network.
A control hub that I keep with me, and sensors placed around the campsite. Each sensor covers about 180°, forming a perimeter watch. Arming and disarming are done with a fingerprint reader — not strictly essential, but fast, secure and pleasant to use. And let's be honest: I really enjoy integrating fingerprint readers into my projects.
Each sensor detects presence, but also its own vibrations. Once the system is armed, the sensors regularly send a signal to the hub confirming that they are present, working and sufficiently charged.
The logic distinguishes the cases: low battery or a degraded signal → just an indication. But if a sensor suddenly disappears when it was fine just before, the system treats this as an anomaly and triggers the alarm.
The system therefore protects itself against several scenarios: someone passing in front of a sensor, a sensor being moved, a sudden loss of signal, an attempt to neutralize it.
Portable form factor · energy-autonomous sensors · reliable wireless communication · avoiding false triggers · detecting neutralization attempts · fast and simple arming/disarming.
This isn't an alarm that goes off on movement: it's a distributed system that monitors its own state.