HealthyPi Move is an open-source biometric monitor in a watch form factor. It supports continuous or intermittent monitoring of vital biometric signals like ECG, heart rate, HRV, PPG, SpO₂, EDA/GSR and blood-pressure trends. HealthyPi Move is designed as a platform for innovation and customization, enabling users to integrate health tracking into their projects and personal wellness routines. The HealthyPi Move comes ready for everyday use and research applications, in one device.

Here are some key features:

• Dual PPG and Single-lead ECG sensors: Two PPG sensors in different locations, one on the wrist and one on the finger. This configuration opens up a range of interesting applications, including blood pressure trending and pulse transit-time measurement. The single-lead ECG sensor provides additional heart-health monitoring capabilities
• Extended Battery Life: A 300 mAh Li-Po battery, combined with the low power consumption of our AMOLED display and smart power management thanks to the nRFConnect SDK, provides up to five days of battery life with normal use.
• AMOLED Display: Bright 1.2" 390x390 pixel full-color AMOLED display with capacitive touchscreen

We designed HealthyPi Move according to the same principles as our larger HealthyPi products: open hardware, open-source software, clinical-grade precision, ease-of-use, and standalone operation without dependence on cloud services or paid subscriptions. The Move can be used for a wide range of applications, including personal health tracking, the development of healthcare-related devices, and even clinical research – with institutional review board (IRB) approval. If you have the resources to Shepherd your device through the FDA (or equivalent) certification and clearance process, you can use it for medical patient monitoring as well, and it already supports most of the capabilities you would need!

Own Your Device & Your Data

Data is the single most valued and traded item in the health industry lately, in part because of the need to train AI models for data-research studies. With the exception of a few open data-sharing platforms such as Physionet, most collected data is locked within proprietary systems where companies can sell it to the highest bidder. With HealthyPi Move, you own your health data. We don’t collect or sell your data, we don’t have a cloud service on which to store your data, and we don’t have a subscription model through which you and others can access your data. You can choose to share it with your health-care provider or with a research study on your own. Or, if you wish to train your own models or carry out your own research studies, you can use our open-source platform to gather data from participants, including yourself.

Truly owning any electronic device today is a challenge, as most devices are designed to be disposable, rather than repairable, with hidden screws, glued parts, and proprietary software. HealthyPi Move is designed to be maintainable and upgradable to protect your right to repair. Broke the display? Simply buy a replacement from our site (or a screen with the same specs from wherever) and replace it yourself. We designed the Move so you can open it up and fix it, which means it’s held together by screws and snaps rather than by glue like most devices. It’s also designed with modularity in mind, so the main board, sensor board, and battery are all easy to replace. Finally, HealthyPi Move is user programmable, so you can write your own algorithms and applications for it.

Backed by the Powerful HealthyPi Move App

The HealthyPi Move app is a powerful companion to the HealthyPi Move, providing you with real-time health insights and control over your device. The same "own your data" principles apply to the app as well: we don’t collect your data, and we don’t have a cloud service on which to store your data. You can choose to share it with your health-care provider or with a research study on your own using CSV, PDF and other export formats.

The app allows you to view signal trends, download ECG records, calibrate blood pressure, and more—all from the convenience of your smartphone. The app is available on Android and the iOS version in coming soon, after review. The app is designed to seamlessly integrate with your HealthyPi Move watch, while storing all your data locally on your device, so you can access it anytime without sharing it with anyone.

And yes, the app is open-source too! You can find the source code on our repo mentioned at this page’s end. The app is written in Flutter, which allows us to support multiple platforms, including Android, iOS, macOS, Windows, and Linux. This means you can use the app on your smartphone or computer to access your health data and control your HealthyPi Move watch.

Sensors & Biometric Signals

The HealthyPi Move is packed with sensors to monitor a wide range of biometric signals. Here are some of the key sensors onboard:

Photoplethysomogram (PPG)

HealthyPi Move comes with two PPG sensors in different locations, which is a first for a wearable device in this form factor. The wrist-based PPG is located under the device and is used for everyday heart rate and SpO₂ monitoring. The finger-based PPG is optional and plugs into the device’s USB Type-C port. It can be used for more accurate SpO₂ monitoring, which is particularly useful under low-perfusion conditions and for blood-pressure trend monitoring. Below is a picture of the HealthyPi Move wrist and finger sensors.The finger sensor is a small board that can be easily secured to your finger using a velcro band or a silicone ring.

HealthyPi Move works with either the wrist sensor or the finger sensor, and can even run both simultaneously. This dual location PPG configuration opens up a new range of interesting applications, starting from everyday fitness tracking to blood pressure trending and pulse transit time (PTT) measurement, all using the same device. HealthyPi Move has two MAX32664 sensor hubs, one for the wrist sensor and one for the finger sensor. They come with medical-grade PPG algorithm libraries that can be used to calculate HR, SpO₂, and BPT values in addition to outputting raw data. The wrist sensor has four LEDs—two green, one red, and one infrared—and two photodiodes for reliable PPG data acquisition. The finger sensor has a MAX30101 sensor module with red and infrared LEDs and a photodiode.

Blood-pressure trending (BPT) is calculated using PPG data acquired from the finger sensor. A tiny sensor board integrated into the wearable finger board features a MAX30101 integrated optical sensor module, and the HealthyPi Move sensor board has an onboard MAX32664D biometric sensor hub, which provides a PPG algorithm library that can be used to calculate SpO₂ and BPT values. Several studies have shown that BPT values calculated from PPG data are comparable to values obtained using traditional cuff-based blood pressure monitors.

Parameters derived from PPG data include:

• Blood-oxygen levels (SpO₂)
• Blood-pressure trends (BPT) - finger sensor required
• Heart-rate
• Heart-rate variability (HRV)

In addition, you can always add your own code to get other parameters—such as pulse transit time (PTT), sleep patterns, etc.—that can be derived using your own algorithms

Electrocardiogram (ECG)

ECG uses the electrical activity of the heart to indicate heart health. HealthyPi Move contains a single-lead ECG with one set of electrodes on the back of the device, which touches the skin of one wrist, and another electrode on the top stainless steel bezel of the device which you can touch with the finger of your other hand, thus forming a Lead-II type ECG configuration.

The ECG data is processed by the onboard SoC and can be visualized in realtime on the display or sent to a smartphone or computer via Bluetooth (BLE). Heart-rate and HRV is also calculated from the ECG data in realtime. Respiration rate is also indirectly derived from the ECG using the EDR method.

Parameters derived from the ECG data include:

• Heart-rate
• Heart-rate variability (HRV)
• Respiration rate
• Other parameters—such as QT interval, QRS duration, etc.—that can be derived using your own algorithms

Galvanic Skin Response (EDA/GSR)

EDA or GSR provide a measure of the electrical conductance of the skin, which varies with its moisture level. This is a good indicator of changes in mental state and can be used to monitor stress levels and emotional response. HealthyPi Move has two electrodes in the back that touch the skin of the wrist and measure the conductance of the skin, which correlates to EDA/GSR activity. GSR/EDA data can be recorded or visualized on the display.

Parameters derived from the EDA/GSR data include:

• Stress level
• Emotional response to stimuli
• Other parameters—such as skin conductance, body composition, etc.—that can be derived using your own algorithms

In addition to the above, HealthyPi Move has the following additional sensors onboard:

• A body temperature sensor (with a sensing pad on the back of the device)
• An inertial measurement unit (IMU) with 6-axis accelerometer and gyroscope to monitor your activity level. The IMU can be used to monitor physical activity, sleep patterns, and other parameters that requires motion sensing.

Onboard Computing & Interfaces

HealthyPi Move is powered by the Nordic nRF5340 dual-core SoC, which has a Cortex-M33 application processor and a Cortex-M33 network processor. The application processor runs the main application, and the network processor runs the BLE stack. The nRF5340 has 1 MB of on-chip flash and 512 KB of RAM, which is more than enough to run the HealthyPi Move application and user applications, with plenty of processing power to spare. The nRF5340 also supports XIP from QSPI flash, which allows largers applications to be run directly from external flash memory without needing to copy the code to RAM first.

The onboard 128 MB of flash is connected through a high speed QSPI interface and can be used to store up to 10 days of processed data, assuming a four-second sampling duration. The device can also be used to store raw data for shorter durations, making it perfect for stand-alone data collection without a smartphone or a computer.

Software Updates & Programming

Since the Zephyr software stack and the nRF Connect SDK both support the MCUBoot bootloader, HealthyPi Move can be updated with new software over the air (OTA) using the BLE interface from the HealthyPi mobile app or through the USB interface from a computer.

If you wish to program the nrf5340 directly with an nRF DK or any other J-Link programmer, you can do so by connecting the SWD pins to our programming adapter board which plugs into the USB Type-C port. The programming adapter board also has a UART interface that can be used to debug the application. The USB Type-C port is internally multiplexed to allow for SWD and UART access, charging, and data transfer. The multiplexing circuit on HealthyPi Move relies on the USB Sideband pins and Debug Accessory Mode (DAM) to achieve this functionality without hindering the normal operation of the USB Type-C port at full speed or fast charging with support for USB Power Delivery (PD).

Features & Specifications

• Microcontroller: Nordic nRF5340 dual-core ARM M33
• Sensors
  • MAX86141 Wrist PPG Sensor with dual green, red, and infrared LEDs and two photodiodes
  • MAX32664C Biometric Sensor Hub for wrist SpO2 and HR measurements
  • MAX30101 Optical Finger PPG Sensor
  • MAX32664D Biometric Sensor Hub for finger SpO2 and Blood Pressure measurements
  • MAX30001 ECG and bio-impedance front-end
  • BMI323 6-DoF IMU for activity and motion sensing
  • MAX30208 Body Temperature Sensor
• Memory: 128 MB NOR QSPI flash memory for data storage
• Display: 1.2 inch, 390x390 pixel Full-color AMOLED display with capacitive touchscreen
• Interfaces
  • Bluetooth Low Energy (BLE) 6.0
  • USB Type-C for data transfer, charging, JTAG and UART access (via USB Type-C Debug Accessory Mode)
  • 1 side push buttons for user input
• Power management: Nordic nPM1300 Single chip PMIC
  • Integrated 800 mA battery charger with USB Type-C Power Delivery support
  • 2x Integrated programmable buck converters for efficient power management
  • Integrated fuel gauge for battery monitoring
  • Integrated load switches for selective power management
  • 300 mAh Li-Po battery
• On-board realtime clock with super-capacitor backup
• Parameters Monitored
  • ECG
  • Heart-rate (from ECG or PPG Wrist or Finger sensor)
  • Heart-rate variability (HRV) (from ECG or PPG Wrist or Finger sensor)
  • PPG (from wrist or/and finger PPG sensor)
  • SpO₂ (from wrist or finger PPG sensor)
  • Blood Pressure (from finger PPG sensor only)
  • EDA/GSR
  • Respiration Rate (ECG derived)
  • Temperature
  • Activity levels and step count
  • Energy expenditure (calories burned)
• Software
  • Firmware based on Zephyr RTOS and nRF Connect SDK
  • Companion apps written in Flutter for Android, iOS, macOS, Windows and Linux
• Dimensions: 43 mm diameter, 13 mm thickness, compatible with 22 mm watch straps

Enclosure Design

The HealthyPi Move enclosure is designed to be simple, slim, accessible, and as light as possible while still being robust enough to hold the necessary sensors and electronics. The current version (shown in various pictures above) is a 3D-printed version that we’ve been using for prototyping and testing. The final version of the enclosure is injection molded and is made of a biocompatible ABS-type material. The enclosure is designed so that the entire PCB and battery assembly can be inserted in one go from the back and secured with screws, no glue required. The enclosure includes a strap-attachment mechanism that accommodates any standard, 22 mm watch strap.

Enclosures are designed in-house on Autodesk Fusion 360 and the source is available on our GitHub repo. Manufacturing of the enclosures is carried out by trusted partners.

The enclosure also includes a unique "Chassis" based design to hold the main PCB, the sensor PCB, and the battery in place, while also protecting the battery if the rest of the device gets damaged. The chassis is held in place by four screws and can be easily removed for repairs or modifications. The chassis design is shown below.

HealthyPi Move went through several hardware iterations and multiple rounds of testing with different components before landing on our final design. Several of those iterations are shown below:

Comparisons

Support & Documentation

HealthyPi Move’s hardware and software are fully open-source, and we provide extensive documentation to help you get started with your own projects. Our design files and software are available in our GitHub repositories:

• HealthyPi Move Hardware
• HealthyPi Move Software
• HealthyPi Move Mobile App

Important Warning

Although HealthyPi Move has many of the features of a medical-grade patient monitoring system, it does NOT have any certifications for medical use and is considered a consumer device for CE and UKCA marking purposes. It is NOT officially approved for medical or diagnostic use. It is your responsibility to ensure your safety when using the device. Furthermore, you should never power the device from a non-isolated power source or connect it to any other medical devices that are not isolated from the mains power supply. If you are planning to use the device for medical purposes, FDA or IRB approval is required. Please consult with your local regulatory authorities for more information.