Wearable motion sensor offers Bluetooth low energy, ANT+, and proprietary 2.4GHz wireless connectivity to provide accurate movement analytics to help prevent injury

‘Physilog 5’ from Gait Up employs Nordic’s next generation nRF52832 multiprotocol SoC to enable post-run form analysis by sports science professionals on smartphones and tablets

Nordic Semiconductor today announces that Lausanne, Switzerland-based motion sensing and analytics company, Gait Up, has launched a new motion sensor, ‘Physilog 5’, that employs Nordic’s nRF52832 System-on-Chip (SoC) to provide the data intensive application with multiprotocol Bluetooth® low energy (previously known as Bluetooth Smart), ANT+, and proprietary 2.4GHz wireless connectivity.

The Physilog 5 motion sensor is IP67 waterproof-rated, weighs only 11g, and comes in a 26.5 by 47.5 by 10mm form factor, providing a compact and versatile wearable device for capturing movement analytics, for example spatial-temporal and foot strike parameters. Designed as both an athletic shoe selection aid to assist with injury prevention, and as a tool to help runners improve their form and technique, the Physilog 5 is attached to the user’s shoe via a supplied laces clip or foot strap, from where the device provides seven dimensional sensing capabilities via its on-board 3D-accelerometer, -gyroscope, and barometric pressure sensor.

The Physilog 5’s sensor data is stored on-board the sensor and is automatically synced to a tablet, smartphone, or PC at custom intervals via Nordic nRF52832 SoC-powered wireless connectivity―where the results can be viewed and analyzed in-app and exported in PDF or XLS formats via a range of professional software packages, including running analysis, gait analysis, and physical activity monitoring (available Q1 2017). Gait Up additionally develops custom algorithms for OEM partners, and offers a free Research Toolkit, giving researchers full control of hardware function and the ability to embed their own custom algorithms.

Nordic’s nRF52832 multiprotocol SoC, a member of Nordic Semiconductor’s sixth generation of ultra low power (ULP) wireless connectivity solutions, combines a 64MHz, 32-bit ARM® Cortex™ M4F processor with a 2.4GHz radio (fully compatible with Bluetooth 4.2, ANT™, and proprietary 2.4GHz RF protocol software) featuring -96 dB RX sensitivity, with 512 kB Flash memory and 64 kB RAM. When launched, the SoC was the world’s highest performance single-chip Bluetooth low energy solution, delivering up to 60 percent more generic processing power, offering 10 times the Floating Point performance and twice the DSP performance compared to competing solutions.

Gait Up required high performance from the Nordic SoC to provide on-board data storage and data manipulation, while demanding efficient battery usage. The flexibility of the nRF52832 allows Gait Up to reach 18 hours of battery life at 500Hz sampling rates with the Physilog 5’s 140mAh Li-ion battery, stretching to more than 1 week between recharges for mission critical applications like elderly monitoring. The nRF52832 SoC has been engineered to minimize power consumption with features such as the 2.4GHz radio’s 5.5mA peak RX/TX currents and a fully-automatic power management system that reduces power consumption by up to 80 percent compared with Nordic’s nRF51 Series SoCs. The result is a multiprotocol wireless solution which offers 90 CoreMark/mA, up to twice as power efficient as competing devices.

“The Nordic nRF52832 was an easy choice for us,” says Alex Russell, Vice President of Business Development at Gait Up. “We needed an ANT+, Bluetooth low energy, and 2.4GHz solution with a processor that could handle our algorithms, and Nordic was the first company to have this combination on a single chip.

“Equally size is important to us, and we found the nRF52832 was the smallest possible way to have this integration. And the hardware was backed by Nordic Semiconductor’s reputation for supplying products that you know will work.”

“This is our first time working with Nordic and I can’t believe we didn’t work with them sooner. We have found the S132 SoftDevice [Nordic’s multiprotocol RF software ‘stack’] an especially useful development tool, and we have used it to perform over-the-air firmware updates.”

“The fitness sector has embraced ANT+ and Bluetooth low energy wireless connectivity and there are still many legacy proprietary 2.4GHz systems in use,” says Geir Langeland, Nordic Semiconductor’s Director of Sales & Marketing. “That was one reason why we ensured that the nRF52 Series offered multiprotocol support. That’s enabled us to supply a chip that allows key fitness product suppliers such as Gait Up to develop a single product that is interoperable with all smartphones, smartwatches and other fitness systems whichever low-power wireless technology the mobiles employ.”

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