A structural health monitoring system that turns hidden corrosion into data. Sacrificial sticker sensors on flexible PCBs corrode at the same rate as the steel they are attached to. As the metal track thins its resistance rises, and that reading is sent over long-range LoRa radio to a cloud dashboard that raises alerts before damage is visible.
How it works
Sensor: a serpentine trace on a 3 cm × 3 cm flexible PCB, read through a Wheatstone bridge and an instrumentation amplifier into an ESP32.
Transport: LoRa (SX1278) to a gateway, then MQTT to a serverless backend.
Three alert states: safe, warning for early corrosion, and critical when resistance changes by more than 20%.
Dashboard: live corrosion level, risk score, vibration, temperature, humidity and resistivity, with trend charts and a daily summary.
The device sleeps between hourly samples to stretch battery life.
