Here’s one way to get a running start on your next health or fitness wearable.

The MAXREFDES104#, better known as the Health Sensor Platform 3.0, is Maxim Integrated’s third-generation wearable reference design. Targeting applications ranging from personal fitness to patient monitoring, the HSP 3.0 hosts:

• The MAX86176 two-in-one optical photoplethysmogram (PPG) and electrocardiogram/electroencephalograpy (ECG/EEG) biopotential measurement analog front-end (AFE) sensor and integrated high-resolution analog-to-digital converter (ADC).
• The MAX30208 ±0.1°C accurate digital skin temperature sensor
• A three-axis accelerometer
• A MAX32666 Bluetooth Low Energy-enabled low-power microcontroller
• A MAX32670 low power microcontroller with floating-point unit
• And the MAX20360 power-management IC

All of these are included on a micro board that contains the two microcontrollers, the PMIC, and flash storage; a sensor board for the two-in-one AFE sensor, ECG electrodes, photodiodes, and accelerometer; another temperature sensor board with the MAX30208 temperature sensor; a BLE dongle; and a completely assembled, 3D-printed wearable enclosure.

In addition, the Health Sensor Platform 3.0 provides access to Maxim’s biometric algorithm hub, located on the MAX32670 micro. The algorithm hub comes complete with heart rate monitoring, oxygen saturation, ECG, sleep quality, stress monitoring, and other algorithms that deliver clinical-grade readings.

The Health Sensor Platform 3.0 in Action

Compared to the previous generation, the HSP 3.0 adds Sp02 measurement and dry electrode capabilities for ECG measurements, the latter of which enables the platform to monitor for a range of health issues, including atrial fibrillation (Afib), sleep apnea, COPD, and even symptoms of infectious diseases like COVID-19. The HSP 3.0 can also be adapted for other dry electrode form factors such as chest patches and smart rings.

The granular resolution required by these tasks is of course afforded by the MAX86176, which is a complete dual-channel optical data acquisition system with a signal-to-noise ratio (SNR) of up to 110 dB and very low input-bias current. Dedicated signal paths for ECG and PPG data afford truly synchronous readings.

Once configured, readings from the various HSP 3.0 sensors can be streamed over Bluetooth to a PC for rapid evaluation and demo development. Wireless transmission of this raw data is possible thanks to the capabilities of the MAX32666 microcontroller.

The entire system has a shutdown current of 0.5 µA, nestling it in the power consumption sweet spot for battery-powered, mobile wearable devices. The MAX20360, what Maxim Integrated is calling the “industry’s most highly integrated PMIC for 24/7 monitoring systems,” supports this ultra-low-power operation with three step-down, step-up, and LDO outputs; a battery charger, input current limiter, smart power selector, and a host of other power management features.

Developers can access hardware design files, including schematics, BOMs, PCB layouts, fab packages, and PCB CAD files from the “Design Resources” tab on the MAXREFDES104# web page. Software files are available for download there as well.

Getting Started with the HSP 3.0

In addition to the hardware mentioned previously, users receive the MAXDAP-USB-C programmer/adapter board with the HSP 3.0, as well as a USB Type A to USB Type C cable.

All that’s needed to get started prototyping your next health wearable is a PC with a spare USB port, which will accept the BLE USB dongle used in the data logging process. You will then download the MAXREFDES104SW PC GUI program and install it on the PC.

After that, just plug in the BLE dongle (if you haven’t already), fire up the HSP 3.0 platform, run the GUI and connect the MAXREFDES104# to it, then click “Start” to begin collecting data using the default platform configuration settings.

That’s it. You’ll be well on your way to making the world a healthier place.

The Maxim Integrated Health Sensor Platform 3.0 (MAXREFDES104#) is available from the Maxim Integrated website for $400. For more information, visit www.maximintegrated.com or check out the resources below.

References:

• Healthcare Sensor Platform 3.0: www.maximintegrated.com/en/design/reference-design-center/system-board/7380.html
• MAX86176 Optical PPG and ECG AFE: https://www.maximintegrated.com/en/products/sensors/MAX86176.html
• MAX30208 I2C Digital Temperature Sensor: www.maximintegrated.com/en/products/sensors/MAX30208.html
• MAX20360 PMIC: www.maximintegrated.com/en/products/power/power-management-ics/MAX20360.html
• MAX32670 Ultra-Low Power Microcontroller and Algorithm Hub: www.maximintegrated.com/en/products/microcontrollers/MAX32670.html
• Maxim Integrated Healthcare Sensor IC Portfolio: www.maximintegrated.com/en/products/sensors/healthcare-sensor-ics