Smart home
Low power wireless connectivity solutions for smart home
Nordic-powered smart meter reader provides homeowners with detailed data on energy usage and efficiency
29
Apr
2024
2024
Oslo, Norway
Watts Live card employs nRF52840 SoC for Bluetooth LE wireless configuration and device supervision
Danish company Watts has launched a retrofittable smart energy solution enabling owners of electrical smart meters to continuously monitor energy consumption in their home. ‘Watts Live’ is a small card that can be easily mounted in the electricity meter of a utility cabinet. The card can be commissioned and configured from the ‘Watts Energy Assistant’ app on the user’s smartphone using Bluetooth® LE wireless connectivity provided by Nordic’s nRF52840 SoC. The configuration process covers unlocking the smart meter with a provided security key and connecting to a local Wi-Fi network.
Once the card is installed and configured, smart meter data can be collected every five seconds and transmitted over Wi-Fi to backend Cloud services or through MQTT to a local MQTT server like ‘Home Assistant’. Watts is also developing a LoRaWAN version for use cases that don’t require live data and where there is no Wi-Fi coverage, such as public infrastructure.
Through the app, the data can provide the end-user with a detailed view of the energy system at home – for example, how much power is purchased or sold to the grid, the voltage level in the home, and the balance between AC power phases. The app also provides the user with consumption measured in cost (based on their personal price scheme) and in carbon-cost (based on current carbon intensity in the power production).
“Watts Live not only makes it possible to find out which appliances use the most power, it also becomes more motivating to save on electricity because you can see the effect immediately,” explains Anders Spur, Director of Product Development, Watts. “Analysis by Watts shows that active users of the Watts Energy Assistant app save on average eight percent on their energy consumption in part thanks to Watts Live.”
Once the card is installed and configured, smart meter data can be collected every five seconds and transmitted over Wi-Fi to backend Cloud services or through MQTT to a local MQTT server like ‘Home Assistant’. Watts is also developing a LoRaWAN version for use cases that don’t require live data and where there is no Wi-Fi coverage, such as public infrastructure.
Through the app, the data can provide the end-user with a detailed view of the energy system at home – for example, how much power is purchased or sold to the grid, the voltage level in the home, and the balance between AC power phases. The app also provides the user with consumption measured in cost (based on their personal price scheme) and in carbon-cost (based on current carbon intensity in the power production).
“Watts Live not only makes it possible to find out which appliances use the most power, it also becomes more motivating to save on electricity because you can see the effect immediately,” explains Anders Spur, Director of Product Development, Watts. “Analysis by Watts shows that active users of the Watts Energy Assistant app save on average eight percent on their energy consumption in part thanks to Watts Live.”
The key factor when choosing the Nordic SoC for the Watts Live card was the upstream support for Zephyr RTOS. This allowed us to quickly develop application [software] in the early stages of product development
Anders Spur, Director of Product Development, Watts
Nordic nRF52840 SoC processor supports Zephyr RTOS
In addition to wireless connectivity, the nRF52840 SoC’s 64 MHz Arm® Cortex®-M4 processor with floating point unit (FPU) performs as the Watts Live card’s application processor and supports the Zephyr real time operating system (RTOS). The configurability and performance of Zephyr make it a best-in-class low power RTOS for power-efficient wireless SoCs like Nordic’s nRF52 Series.
“The nRF52840 was a very good fit for our project due to the SoC’s powerful processer and generous RAM and Flash memory, which are important for complex IoT products with [many] features, while Bluetooth LE connectivity was needed for configuration purposes,” says Spur.
“But the key factor when choosing the Nordic SoC for the Watts Live card was the upstream support for Zephyr RTOS. This allowed us to quickly develop application [software] in the early stages of product development, even before first prototypes were produced, reducing risk and time-to-market.”
Qualified Nordic engineers help address development issues
“In addition, Nordic’s engineers are highly qualified, they contribute high quality software features, and quickly address potential issues and bugs.”
