OMNI20WUNE

A battery-powered IoT device that reads water meters and reports their readings over NB-IoT.

• Company: a DATAKORUM S.L. device (www.datakorum.com).
• My role: hardware and firmware.
• Microcontroller: STM32U575, an ultra-low-power Arm Cortex-M33.
• Connectivity: Quectel BC660K, NB-IoT.
• Meter interface: the protocol defined by the Spanish standard UNE 82326:2010.
• Capacity: up to 50 water meters per device.
• Service life: 12 years.

How it is put together.

The meters hang off one of the STM32U575's UARTs, through custom interface hardware between that UART and the meters. The firmware speaks the UNE 82326:2010 protocol over it, collects the readings, and hands them to the BC660K, which carries them to the network. A 12-year service life on battery sets the same rule as in PARK20: the microcontroller sleeps in its lowest-power modes between readings, and the modem is awake only while it reports.