Bluetooth Low Energy wearable ring measures oxygen saturation and pulse rate


MegaHealth’s Medical Pulse Oximeter employs Nordic’s nRF52832 SoC to wirelessly sync key health metrics to user’s smartphone

Nordic Semiconductor today announces that MegaHealth Technologies, a Hangzhou, China-based medical technology company, has selected Nordic’s nRF52832 Bluetooth® Low Energy (Bluetooth LE) System-on-Chip (SoC) to provide the processing power and wireless connectivity for its ‘ZG-P11D Medical Pulse Oximeter’, a smart pulse oximeter with a lightweight, waterproof ring-based form factor making it suitable for continuous wear on the finger through the night and over extended periods. The Medical Pulse Oximeter is CFDA-certified and widely applied in hospitals.

The Medical Pulse Oximeter uses red light and infrared sensors with different absorption rates when passing through the wearer’s body. Based on the data obtained for the absorption rates of the different wavelengths and using proprietary signal processing algorithms, the device detects changes in the wearer’s blood oxygen saturation (SpO2) and pulse rate (PR). SpO2 is an important physiological parameter reflecting respiration and ventilation function.

The nRF52832 SoC acts as the Medical Pulse Oximeter’s core microcontroller thanks to the SoC’s powerful 64MHz, 32-bit Arm® Cortex® M4F processor which enables SpO2 signal acquisition and algorithm operation. The Nordic SoC’s 512kB Flash memory is sufficient to easily store and record the data, while the 64kB RAM is ample for the device’s algorithm filtering requirements.
Nordic’s nRF52832 SoC uses a Bluetooth LE protocol stack that superbly balances power consumption and real-time performance
Jan Wang, MegaHealth

In addition, the Nordic SoC provides low latency Bluetooth LE wireless connectivity enabling data to be periodically transmitted from the device to an individual’s Bluetooth 4.0 (and later) smartphone. Through MegaHealth’s iOS- and Android-compatible partner app, the user can then view daily, weekly, and monthly health reports featuring blood oxygen, heart rate, and other key health metrics, allowing the individual to monitor their own personal health at home, or on the move, and provide relevant information to a medical professional as required. When the user is sleeping, the device’s built-in sleep apnea alarm monitor also remains connected to their smartphone via the Bluetooth LE link.

The Medical Pulse Oximeter uses a custom arched soft-pack lithium battery that lasts for more than 20 hours prior to recharge, thanks in part to the low power characteristics of the Nordic SoC. The nRF52832 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

Nordic’s nRF52832 multiprotocol SoC combines the Arm processor with a 2.4GHz multiprotocol radio (supporting Bluetooth 5, ANT™, and proprietary 2.4GHz RF protocol software) featuring -96-dB RX sensitivity. The nRF52832 is supplied with Nordic’s S132 SoftDevice, a Bluetooth 5-certifed RF software protocol stack for building advanced Bluetooth LE applications. The S132 SoftDevice features Central, Peripheral, Broadcaster and Observer Bluetooth LE roles, supports up to twenty connections, and enables concurrent role operation.

“Nordic’s nRF52832 SoC uses a Bluetooth LE protocol stack that superbly balances power consumption and real-time performance,” says Jan Wang, Co-founder of MegaHealth. “The clear message-driven model provides a convenient means of programming, allowing our developers to put as much energy as possible into application development.

“Further, Nordic provides complete and comprehensive reference designs and fast technical support.”