Wearable, Open Vital Sign Monitoring Dev Kit

Reliable health monitoring has traditionally required that we tether ourselves to machines capable of recording our vital signs around the clock. Outside of a clinical setting, however, this is rarely practical. We developed HealthyPi v4 in part to address this challenge. Building upon its predecessor, HealthyPi v4 is a fully open source, standalone vital signs monitor with wireless and wearable capabilities.¹

HealthyPi v4 measures the following parameters in real-time and with high accuracy:

• Electrocardiogram (ECG) data, heart rate, and heart-rate variability
• Respiration based on an impedance pneumograph
• Pulse oximetry (SPO₂)
• Body temperature

HealthyPi v4 sets a new standard for mobility, wearability, and wireless connectivity. By enabling continuous, real time monitoring of physiological data, it not only provides valuable insight into health and wellness indicators, it opens the door to areas of research that were not previously accessible.

Perfect for Researchers and Developers

• Students and researchers: Recording and streaming data from a standard vital signs monitor typically requires the use of proprietary software and is, in fact, anything but “standard.” HealthyPi v4 relies on open source software that provides an easier off-the-shelf interface to health related data. Better still, you can build your own custom functionality into that software. The result is an intelligent, wireless monitoring system that is more versatile, more effective at capturing accurate data, and more affordable.
• Developers: If you are a designer of devices related to health and wellness, especially in the booming market for wearables, HealthyPi v4 is extremely useful for prototyping. If you like the results of a given prototype, you can take the hardware and software functionality you have developed and integrate them into your design with minimal guesswork.
• Global public health: For regions of the world in which professional health care is relatively scarce – and where the cost of conventional patient monitors can be prohibitive – HealthyPi devices can serve as an important stopgap. With support for standalone use and the addition of Bluetooth Low Energy (BLE), HealthyPi v4 is now more accessible than ever.

Features & Specifications

Specifications

• Microcontroller and wireless connectivity: ESP32, in WROOM32 module format, with a Dual-core Xtensa 32-bit CPU, 4 MB of on-board flash, Wi-Fi, and support for BLE
  • Wireless interface: Wi-Fi and Access Point (AP) modes, a 2.4 GHz radio with an on-board PCB antenna that is compatible with Bluetooth 4.2 and BLE
  • Firmware programming: Supports Arduino IDE as well as Espressif ESP-IDF
• Sensors:
  • ECG and respiration front end: Texas Instruments (TI) ADS1292R 24-bit analog front end with signal-to-noise ratio (SNR) of 107 dB
  • Pulse oximetry front end: TI AFE4400 pulse oximetry front end with integrated LED driver and 22-bit ADC
  • Temperature sensor: Maxim MAX30208 digital body temperature sensor for monitoring skin temperature
• Form factor: Raspberry Pi HAT form factor (65 mm X 56 mm)

Power Management

HealthyPi v4 also includes an on-board power management system for use with a rechargeable Lithium Polymer (LiPo) battery, making it a truly wearable development platform. A simple physical switch can be used to toggle between continuous mode, for use as a Raspberry Pi HAT, and wearable mode, which allows HealthyPi v4 to function as a standalone unit.

Ports & Interfaces

1. 40-pin Raspberry Pi HAT connector: standard HAT-compatible headers for connecting to any Raspberry Pi
2. Qwiic connectors (x2): Connect any Qwiic-compatible board for virtually limetless I²C sensor modularity
3. USB-CDC: On-board USB-to-UART converter for programming and data transfer
4. Sliding mode switch: Easily transition between wearable mode and HAT mode
5. Power switch: Turn the device on and off

Using HealthyPi v4

Android App

HealthyPi v4 makes it easy to monitor vitals. Just download the HealthyPi v4 app for Android and connect through BLE. HealthyPi v4 devices will appear on the homepage of the app. After you select a device, heart rate, respiration rate, temperature and SpO₂ levels will be displayed. An additional screen renders the real-time ECG waveform. The HealthyPi v4 is also compatible with several standard heart rate monitor apps.

Webserver Mode

Activating webserver mode allows you to stream live data over the local network. Simply push a button while starting up the device, and it will enter Wi-Fi Access Point (AP) mode. You can then connect to the “HealthyPi” Wi-Fi network using your computer or mobile device and point your browser to http://Healthypi.local. The HealthyPi home page will display live vitals as well as plots. This page also provides Over-The-Air (OTA) software and firmware updates.

HealthyPi v4 maintains full compatibility with HealthyPi v3 through its continuous mode, which streams real-time data to a Processing-based application that is compatible with Raspberry Pi devices and desktop platforms (including Mac, Windows, and Linux). Upon successful connection, ECG, respiration, and PPG data will be displayed along with computed heart rate, respiration rate, SpO₂, and temperature readings.

No Programming Required, but Fully Hackable

HealthyPi v4 ships with firmware that enables all of this funcitonality out-of-the-box. If you want to make changes to the firmware, however, you will find the Arduino IDE – which is compatible with Mac, Windows, and Linux – easy-to-use for beginners but flexible enough for advanced users. In addition to Arduino IDE, HealthyPi v4 also supports Espressif IDF, so you can code in whichever environment you prefer.

We have been working behind the scenes on Arduino C++ helper libraries and will share additional examples sketches and original hardware schematics on our GitHub repo once the campaign has ended.

Comparison with HealthyPi v3

Below are a few key similarities and differences between the HealthyPi v4 and the HealthyPi v3:

What’s Included

HealthyPi v4 HAT Kit

Each HAT Kit includes:

• HealthyPi v4 main board
• 1000 mAh battery
• Three-electrode cable with ECG “snap connectors” on one end and a stereo connector on the other
• Sheet of 20 single-use ECG electrodes
• Finger-clip SpO₂ probe with a Nellcor-compatible DB9 connector
• Qwiic-based temperature sensor
• HAT mounting kit with headers and screws for stacking HealthyPi v4 atop a Raspberry Pi

HealthyPi v4 Complete Kit

This kit has all you need to quickly put together a standalone monitor. Each kit contains everything in the HAT Kit, plus:

• Raspberry Pi 3 Model B+ computer
• 16 GB microSD card with Raspbian and HealthyPi software
• Official, 7” Raspberry Pi touchscreen LCD display
• SmartiPi Touch enclosure for the Pi and the display
• Isolated, medical-grade (5 V, 2.5 A) USB wall power adapter (100-240 VAC) with snap-on plugs for the following regions: US, EU, UK, and AU

Manufacturing Plan

Our team, which is based in Bangalore, India, has expertise in hardware testing and inspection. We also have our own manufacturing facility, which is equipped to handle both assembly and testing of the HealthyPi v4 hardware.

We are sourcing HealthyPi v4 components from well-known vendors, including Espressif, TI, Digi-Key, and Mouser. This includes smaller components, such as capacitors and resistors, which helps us ensure quality, consistency, and reproducibility. We have run a number of Crowd Supply campaigns – including HealthyPi v3, HeartyPatch, and Sensything – all of which were successfully funded, manufactured, and delivered to backers.

As you might imagine, based on the above list of related projects, we have already been through several prototyping stages. After many iterations, we believe we have arrived at the perfect balance of performance and ease-of-use.

Shipping & Fulfillment

Due to the high cost of shipping, and given the high volume of orders expected, the amazing people at Crowd Supply will be handling fulfilment. All orders will ship from Crowd Supply’s warehouses in the United States.

Please see the Crowd Supply Guide if you have questions about shipping. Backers are responsible for paying import duties and taxes, if applicable.

Risks & Challenges

Having our own in-house production capability greatly reduces the risks associated with quality control and testing. If we exceed capacity, we have strong relationships with reliable, China-based assembly and production partners. HealthyPi v4 has been through many different hardware iterations and has survived repeated rounds of testing with different components, all of which bodes well for the reliability of its design.

While all hardware projects are exposed to the risks associated with component shortages, shipping delays, and equipment breakdown, we have learned a great deal from previous projects. We are familiar with the factors that can cause delays, and we take preemptive action to avoid them. We will do our best to resolve any such issues quickly and will always keep you updated about changes to our estimated schedule.

Important Warning

Although HealthyPi v4 has many of the features of a medical-grade patient monitoring system, it does NOT have any certifications (FDA, CE, IEC, etc.) and 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.