European smart utility meter gateway powered by harvested solar energy

German industrial IoT solutions specialist, Lobaro, has selected Nordic’s nRF9160 low power SiP with integrated LTE-M/NB-IoT modem and GNSS for its ‘Solar Wireless M-Bus Gateway’ (LOB-GW-SUN-WMBUS). The smart utility meter gateway can record data from up to 500 commercially available consumption meters including water meters, heat meters, and heat cost allocators. It operates perpetually on harvested solar energy alone, making it the first gateway of its type that to not use mains-power or a non-rechargeable battery, according to the company. 

Harnessing solar energy

Energy harvesting is performed by the ADP5091 ultra low power management unit. The nRF9160 SiP was designed to minimize power consumption and, depending on operational parameters, can operate solely off harvested solar energy, a feature that enables wireless cellular IoT sensors to deliver significant sustainability advantages. The gateway uses a 3.8 V supercapacitor (LIC type) as an energy reservoir. The supercapacitor technology is similar to a Li-ion battery but can be recharged 10 times more frequently. The gateway remains in an energy-saving mode for most of its operating time only waking up at pre-programmed intervals. 

The Solar Wireless M-Bus Gateway is ideal for applications where metering data is needed at a higher frequency than possible with battery-powered gateways – for example, in predictive maintenance and energy cost optimization applications, or billing use cases. 

The Solar Wireless M-Bus Gateway employs the Nordic nRF9160 SiP to provide Low Power Wide Area (LPWA) networking of European M-Bus (868 MHz) or Sensus RF consumption meters using NB-IoT or LoRaWAN or a combination of both. M-Bus (short for ‘Meter-Bus’) is a European short-range standard for the remote wireless reading of water, gas, electricity, heat, and other consumption meters. By combining cellular IoT and LoRaWAN in a single gateway, the device ensures European utility and buildings management customers are not restricted to a single LPWAN wireless technology. Users can choose between connectivity options based on local network availability and wireless signal coverage. 

Easy over-the-air updates

The nRF9160 SiP’s NB-IoT cellular IoT connectivity provides a large payload capacity and simple over-the-air device firmware update (OTA-DFU) capability for devices installed in the field. If the IP66-rated gateway is installed outdoors, metering data can be easily uploaded multiple times per day to the Cloud where it is shared to the ‘Lobaro IoT Platform’ for further processing. If installed indoors near a window, daily data uploads to the Cloud are possible.

Nordic’s nRF9160 SiP’s 64MHz Arm® Cortex®-M33 dedicated application processor provides sufficient computational power to not only supervise the LTE-M/NB-IoT modem’s cellular connectivity but also all other product functionality. Lobaro is currently running proprietary LoRaWAN and Wireless M-Bus stacks on the embedded processor with its 1 MB Flash and 256 KB RAM.

“Based on previous projects we know that Nordic’s nRF9160 SiP is a good fit for a gateway solution like our Solar Wireless M-Bus Gateway,” says Theodor Rohde, Managing Director of Lobaro. “We chose Nordic’s nRF9160 SiP for its compact form factor and low power, especially the automatic power and clock management. The tight integration of the modem also helps in low power applications.

“Beyond smart metering use cases, Lobaro welcomes developers on tight schedules wanting to combine any other sensors with Nordic’s nRF9160 SiP.” 

• About Lobaro
• About nRF9160
• About Nordic Semiconductor