[Update: The information from Shelly about a new “Cortana M3” processor is incorrect, we’ve been contacted by Silicon Labs, and there’s no Cortana M3 microcontroller from the company, Shelly is just using one of the company’s Cortex-M3 based WiFi solutions (SoC or module). The article remains unchanged]
WiFi is one of the most convenient ways to connect IoT devices as it’s omnipresent, low-cost, and the range is ideal for the typical smart home. That’s all good until you start to power the device with a tiny battery, as WiFi consumes much more power than Zigbee, Z-Wave, or Bluetooth.
Over five years ago, Rockchip RKi6000 WiFi SoC promised Bluetooth 4.0 LE power consumption numbers allowing coin-cell powered WiFi devices, and there were some demos the following year, but I’ve yet to see a consumer device based on the solution.
This brings me to the main topic of this post: Shelly Motion, a soon-to-be-launched smart motion sensor said to be powered by Silicon Labs Cortana M3 Cortex-M3 WiFi microcontroller, and capable of offering over one year of battery life while connected to WiFi thanks to an ultra-low power consumption of less than 300 uA. The company explains this is equivalent to the power consumption of Silicon Labs Zigbee, Z-Wave, or Bluetooth chips, and Cortana M3 embeds the most-efficient WiFi radio in the world. The one-year battery life is based on a real use case of 6 hours of motion detection a day, and without motion detected battery life would be close to 5 years while being always-connected to WiFi, and 3 years with 3 detections per day. The battery capacity is 7,000 mAh.
Shelly Motion also supports near real-time response with under 200ms response time, 200 levels of sensitivity, earthquake detection, sunset/sunrise scenes, pet detection (rejection), and more. It can communicate with the home automation gateway or the cloud over MQTT, CoAP, REST using TLS encryption. The new device was introduced at IFA 2020 together with Shelly 4Pro Plus” 4-way relay for DIN-mounting.
You must think there must be tons of news about Silicon Labs Cortana M3 all over the web, but at the time of writing, it’s close to impossible to find any information, except on Shelly’s IFA2020 product page where there’s plenty of information about the motion sensor as one would expect, but very limited additional details about Silicon Labs’ latest wireless microcontroller.
So we’ll have to wait a little longer for the official announcement. As you probably know, Cortana is Microsoft’s voice assistant, so I would not be surprised if Silicon Labs has to change Cortana M3’s name to something else.
Thanks to Andreas for the tip.