Wearable muscle performance monitor offers Bluetooth low energy and ANT+ wireless connectivity to provide athletes with instant feedback on training intensity

Nordic Semiconductor today announces that Cambridge, MA-based startup, Humon, has launched its new wearable muscle performance monitor, the Hex, initially targeted towards endurance athletes, employing Nordic’s nRF52832 System-on-Chip (SoC) to provide the device with multiprotocol Bluetooth^® low energy and ANT+ wireless connectivity.

The Humon Hex helps people engaging in endurance sports or interval training improve their performance by employing near-infrared spectroscopy to measure the way their muscles are using oxygen, providing real-time feedback on when and how hard to push themselves. The water resistant device is strapped to the user’s thigh―the largest muscle most commonly exerted during athletic activities―from where LEDs emit light into the muscle tissue, and detectors measure the intensity of light that propagates through the muscle, allowing the calculation of the muscle’s hemoglobin saturation, a key metric in ensuring appropriate exercise intensity.

The data is processed in real-time by Humon proprietary algorithms, and using the nRF52832 SoC’s Bluetooth low energy or ANT+ wireless connectivity, syncs to the user’s Bluetooth 4.0 (and later) smartphone, tablet, or compatible Garmin watches. The generated metrics instantly inform the user when they are exerting themselves within the limits of their threshold and are not in danger of ‘hitting the wall’, or if they need to reduce the intensity of their workout if there is a large deficit of oxygen in their muscles.

In the absence of a receiver, data is stored on the device and can be downloaded at the next opportunity to the Humon app on the user’s smartphone or tablet for a post-workout performance analysis.

Weighing only 32g and with a 60.5 by 57 by 13.8mm form factor, the Humon Hex employs a wirelessly rechargeable Li-Poly battery that provides up to 12 hours of continuous operation, or two weeks of workouts, between recharges, thanks in part to the ultra low power consumption of the nRF52832 SoC. 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 Bluetooth low energy solution which offers 58 CoreMark/mA, up to twice as power efficient as competing devices.

Nordic’s nRF52832 Bluetooth low energy SoC, a member of Nordic’s sixth generation of ultra low power (ULP) wireless connectivity solutions, combines a 64MHz, 32-bit ARM^® Cortex^® M4F processor with a 2.4GHz multiprotocol radio (supporting Bluetooth 5, ANT™ and proprietary 2.4GHz RF software) featuring -96dB RX sensitivity, with 512kB Flash memory and 64kB 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.

“As a core part of our design, we needed to have both Bluetooth low energy and ANT+ in our design, and Nordic provides superior integration over other competitors when it comes to integrating ANT+,” says Evan Demers-Peel, Senior Hardware Engineer, Humon. “This on top of all other functionality—the large Flash memory size, the large RAM—is why we chose the nRF52832 for the design of the Humon Hex.

“After this experience, we see Nordic Semiconductor as an organization that we will consider on every new design in the future.”