ProtoCentral Electronics Private Limited


An ECG patch with HRV monitoring that's open source, affordable, and Wi-Fi/Bluetooth connected.

$33,414 raised

of $1 goal

Not Available
Nov 13 2017
funded on

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HeartyPatch is a completely open source, single-lead, ECG-HR wearable patch with HRV (Heart Rate Variability) analysis. It is based on the popular ESP32 system-on-a-chip. By using low-cost, highly-integrated components, we are able to keep the BOM’s cost low, while the simplicity of the circuit design means future expansion will be easier. HeartyPatch can be used both as a lifestyle device for managing fitness and stress as well as for diagnostics and medical research, with the potential for even more interesting applications.

Currently available low-cost, wearable heart monitors are usually based on less accurate optical measurements while the actual electrocardiography-based monitors are either too expensive or difficult to use. Similarly, heart-rate variability (HRV) data is used in fitness and training, but can also be used to detect some of the basic cardiac arrhythmias. Getting accurate R-R intervals for HRV studies is also tricky with most heart-rate monitors.

What is Heart-rate Variability?

Heart-rate variability, or HRV, is a measure of the variance of heart-rate in real-time. More specifically, it is the time difference between two R-R intervals (the signal peaks) in an electro-cardiogram (ECG or EKG) plot.

Studies of heart-rate variability have shown that HRV can be indicative of some common forms of arrhythmia, including atrial fibrillation (AF) and atrial tachycardia (AT), among others. HRV can be detected with a single lead ECG, like HeartyPatch, which, for cardiac patients being monitored for such forms of arrhythmia, is much easier to wear long term than a full Holter configuration (three or five leads).

In fitness applications, some high-performance athletes train using biofeedback for heart-rate control and also for knowing when to start and stop training (based on heart-rate).

HRV has also be known to reflect emotion, mood, anxiety, and stress. When such psychological events happen, there is a known pattern of variance in heart rate. This makes HRV useful tool for studying mood and managing stress in people who are prone to such psychological states.

Finally, since HeartyPatch can detect individual heart-beats in real-time, it can also be used in the areas of design and non-medical wearables to detect heart beats to activate lights or any other form of feedback. Cardio-biofeedback is an example of controlling heart-rate.

Who Needs HeartyPatch

(for continuous event monitoring)

(for precision cardio training)*

(as a reference design)

(because knowing your own heart-patterns is cool)

*Activities that cause sweating can prevent adhesive electrodes from adhering properly.

HeartyPatch Modes of Operation

HeartyPatch is open source. This means that the software on the device can be modified to work in any way you choose, providing access to raw heart-rate and inter-beat interval (IBI) data. Because of this flexibility, HeartyPatch can be operated in any or all of the following modes.

HRV analysis showing different types of arrhythmia

Bluetooth Functionality

HeartyPatch supports Bluetooth Low Energy (BLE) functionality with the heartrate monitor profile giving the real-time heartrate as well as R-R intervals. This means that it is now compatible with all common heartrate monitoring and HRV (Heart Rate Variability) apps.

Here is the device working with Elite HRV, a common HRV app that is free for most uses while also having a paid version:

HRV apps such as this provide basic characteristics like heartrate, variability, signal quality (which in this case was pretty good!) and statistics such as min HR, max HR, mean, and average. HRV-specific statistics such as RMSSD, NN50, PNN50 can also be calculated.

HeartyPatch can provide calculated values from the device itself over Bluetooth or Wi-Fi (with different firmware). Below is a screenshot of the data sent by HeartyPatch to a TCP socket terminal.

If you would like to explore other HRV apps, you can search on the Google Play Store or Apple App Store for several options.

HeartyPatch, out-of-the-box, supports any Android or iOS app that supports the standard BLE heartrate profile.

Technical Specifications:

How HeartyPatch Compares

HeartyPatch has considerable advantages over other low-price heart monitors:

What’s in the Kit?

Basic Kit

3D Printed Case

This enclosure allows for comfortable longer-term use. It is a clear 3D printed "clam-shell" style enclosure with snap-fits to close the two parts together. This is not an injection molded commercial-grade enclosure, but is 3D printed with PLA. The enclosure can be bought from this page along with the HeartyPatch, or you can download the open source 3D model from our website and print it out on any available 3D printer.

Open Source - Open Hardware

Open source means that a product truly belongs to the owner. You can understand, change, and use your hardware and software however you see fit. This control is especially important when it comes to health. So HeartyPatch is an open source project with files available on our GitHub repository:

Manufacturing Plan

Manufacturing, assembly, and testing will be done at our own facility in Bangalore, India. We have our own assembly and testing facility for low volume production. This includes a small pick-and-place machine, ovens, and microscope inspection equipment. We also have our own team with testing and inspection expertise at our office/assembly facility in Bangalore, India.

All the components for HeartyPatch are from authorized, well-known vendors, primarily Digi-Key. This includes even smaller components such as capacitors and resistors to ensure we get consistent signal quality and reproducibility of signals each time, every time.

We have already successfully run, completed, and delivered the HealthyPi-v3 campaign right here on Crowd Supply. All deliveries have been on time as promised and we know the challenges associated with crowdfunding which puts us in a better position to deliver on time.

We have already fully executed two revisions of the HeartyPatch design, and the device is currently stable.

Shipping & Fulfillment

Due to the high cost of shipping and given the high volume of orders expected, Crowd Supply will be handling fulfillment. All orders will ship from Crowd Supply headquarters located in Portland, OR in the United States. Please see for shipping details.

Customs import duty and taxes may apply for certain countries and certain customers. All the clearance procedures will be performed by the courier, but the customer is responsible for paying any import duties/taxes, if applicable.

Risks & Challenges

As HeartyPatch functionality is currently stable and tested, we don’t foresee any issues that aren’t inherent in manufacturing a product generally. There is always a chance of component shortage or equipment down time that restult in delivery delays. Shipping can also hold back any project if packages are lost or damaged in transport. We’ll keep the delivery timelines as up-to-date as possible and provide regular status updates during production.

A Note About BLE on the ESP32 Module

The ESP32 device on HeartyPatch does not currently support Bluetooth operation in Low Energy Mode (as of September 28, 2017). It supports all the BLE profiles as expected, but the baseband works only in Bluetooth Classic mode. This means that the power consumption by the Bluetooth radio when connected WILL NOT meet the expectations of BLE. This is supposed to fixed in the next release, but could take longer, according to the Espressif team. This will ONLY affect the battery life of the device and does not affect functionality in any way.

Important Notice: Although it has all the features of a clinical grade heart monitor and could function as one, HeartyPatch does not have any certifications (FDA/CE/IEC) and is not approved for medical or diagnostic use. It is your responsibility to ensure your safety when using the device. Never power the device from a non-isolated power source.

In the Press

Hackster News

"If you’re an avid runner or cyclist, you may use a heart rate monitor to ensure that your exertion level is... proper. Taking this one step further is the HeartyPatch, an open source ECG patch that measures the electrical activity of the heart..."


"Meet the HeartyPatch: an open source connected patch with WiFi and Bluetooth that lets you measure your ECG, heart rate, and HRV. "



"Projects like this are what the Hackaday Prize is all about, Changing the world for the better. Medical devices cost an arm and a leg so it’s always great to see medical hardware brought to the Open Source and Open Hardware scene."

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Produced by ProtoCentral Electronics Private Limited in Bengaluru, India.

Sold and shipped by Crowd Supply.

Support Us!


HeartyPatch Basic Kit (Early Bird)

Includes the HeartyPatch PCB with ECG button connectors, sheet of 10 disposable electrode pads, a 450 mAH LiPo battery and a Micro-USB cable for programming and charging. Special early bird pricing for our first supporters.

$87 $8 US Shipping / $18 Worldwide

HeartyPatch Basic Kit

Includes the HeartyPatch PCB with ECG button connectors, sheet of 10 disposable electrode pads, a 450 mAH LiPo battery and a Micro-USB cable for programming and charging.

$95 $8 US Shipping / Not Available Outside US

About the Team

ProtoCentral Electronics Private Limited

Bengaluru, India  ·   Protocentral  ·   protocentral  ·  ·

ProtoCentral is an open-source hardware design, development, and manufacturing company based in India. We are strongly committed to the development of open source hardware. Most of our products are open source and anyone is free to re-use them for their own projects. We are also working toward open sourcing more hardware, especially for the medical and biotech domains.

Ashwin K Whitchurch
CEO / Project Manager
Manikandan S
Lead Hardware Engineer
Venkatesh Bhat
Lead Software Engineer
Joice TM
Software Engineer
Biswajit Ojha
Lead Operations Manager
Manigandan B
Assistant - Assembly & Testing
Yasaswini Ravuri
Software Engineering Intern

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