LoRaWAN v1.1 smart water meter designed for years of battery-powered field operation.
A volumetric and ultrasonic smart water meter designed for smart city deployments. The core challenge was achieving years of battery life while maintaining reliable LoRaWAN connectivity and accurate measurement.
Designed on STM32L0, one of the lowest-power STM32 variants available. Custom glass LCD display designed to minimize power draw during readout. PCB designed in Altium with careful attention to leakage current paths and quiescent draw of every component.
Full LoRaWAN v1.1 stack implemented from scratch in C. Sleep architecture puts the device in stop mode between measurement and transmission windows. Wake sources carefully managed to avoid unnecessary current draw.
Achieved target battery life through a combination of hardware and firmware decisions. Low-power oscillator used for timekeeping in sleep. ADC sampling scheduled to minimize active time. LoRaWAN adaptive data rate used to reduce transmission power when signal conditions allow.
Deployed across smart city infrastructure. Gateway and network server also designed and deployed as part of the same project, providing end-to-end ownership of the full LoRaWAN stack.