HealthyPi v4 - Unplugged

A wireless, wearable, open source vital signs monitor powered by ESP32

Oct 09, 2019

Project update 3 of 13

What Makes This a Wearable Platform?

by Ashwin K Whitchurch

HealthyPi v4 stands out from its predecessor, HealthyPi v3, because of one major additional feature: we made it a wearable development platform.

HealthyPi v4 in Wearable Mode

Why make HealthyPi v4 wearable? So that it can provide live, seamless, and stable vitals on the go. You can pair your smartphone with the device and stream live vital signs to the screen of your mobile. Below are some of the major features of HealthyPi 4 that make it suitable for wearable device development.

1. Bluetooth Low Energy (BLE)

HealthyPi v4 is powered by the ESP32 SoC module, which supports pairing with smartphones through BLE. BLE is widely used in wearable devices because its low power requirements allow it to function for a long time without charging. HealthyPi v4 also supports pairing with other IoT devices for use in mesh networks. BLE 4.2 adds improved security capabilities.

Data measured by Healthy Pi v4 is accessible through standard BLE services for Heart Rate, Pulse Oximeter, Health Thermometer and Battery Service, as well as custom services for ECG and respiration. Notifications are used to transmit data from HealthyPi to the app.

Service NameUUID
Heart Rate Service0x180D
Pulse Oximetry Service0x1822
Health Thermometer Service0x1809
Battery Service0x180F

BLE Services in HealthyPi v4

2. Battery powered

HealthyPi v4 can be used as a standalone device, without external interfaces or power. Powering the device with a LiPo rechargeable battery improves its portability.

HealthyPi v4 Battery

The provided 1000 mAH battery – which includes built-in overvoltage, overcurrent, and minimum voltage protections – should be sufficient for most use cases, but you can connect any 3.7 V LiPo battery directly to HealthyPi v4 through the onboard 2-pin JST-PH connector.

3. Introducing the HealthyPi app

Monitoring the human physiological data associated with day-to-day activities becomes much simpler with the HealthyPi app, which will be made available in app stores, for both Android and iOS devices, after the campaign ends. Its source code will be released at that time as well.

The HealthyPi app is used to communicate directly with HealthyPi v4 hardware, through the same BLE services mentioned above, and can display all vital signs on a single screen.

HealthyPi App

HealthyPi v4 is a powerful tool, and the HealthyPi app opens up new possibilities for using it to monitor vital signs outside of traditional settings. Among other features, it is capable of displaying respiration and ECG data. A simulation of the latter function is shown below:

HealthyPi v4 ECG Streaming

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