HealthyPi Move is already packed with sensors that can be used to monitor a wide range of health parameters, and we’re adding a new sensor to the mix. The new sensor is a wrist-based photoplethysmography (PPG) sensor that can be used to measure Heart-rate (HR) and blood oxygen saturation (SpO2) levels from the wrist itself, without the need for a separate finger sensor. Blood-pressure trend (BPT) monitoring will still required the finger sensor. The new wrist sensor makes HealthyPi Move easier to use and more comfortable for everyday use as well as advanced research applications.

We had initially planned this as a future upgrade, but—after receiving valuable feedback from quite a few backers—we decided to include a wrist sensor in the current production design. All orders will now include the device with the onboard wrist sensor and an additional cable-based finger sensor. Plugging in the finger sensor will automatically disable the wrist sensor, so it’s easy to use the wrist sensor for everyday monitoring and the finger sensor when you need more accurate measurements. (It’s also possible to use both sensors simultaneously for research applications. We’ll talk more about that in a future update.)

The new sensor module is based on the Analog Devices MAXM86146 Optical Sensor and a discrete LED setup with two green LEDs, one red LED, and one IR LED. The MAXM86146 also contains a MAX32664C sensor hub loaded with algorithms to process the PPG signals and provide the heart rate and SpO2 values.

We already covered the basic principle and applications of PPG in our previous update. With this addition, HealthyPi Move is now the first wearable device to have both wrist-based and finger-based PPG sensors in a single device!