Blog 5 - Big Heart 2.0 "A Bigger Heart " (Prologue)

"A Bigger Heart" Project Specifications

Class Friday 14th/3rd/2025

This weeks class Jason discussed the possible IoT use case that the group will work on, looking to use our knowledge accumulated from the previous seven weeks, to create an IoT artefact that follows an Analog Input/ Analog Output design ethos.

Introduction

After a few weeks of developing and testing HRV-related components, our group decided to fully commit to building a proper IoT-based heart monitoring system. The idea came from previous class discussions, where we explored using analog sensors, data analysis, and cloud dashboards to make heart signals more accessible and meaningful. We’ve broken the project into two-week sprints to stay on track.

This blog covers the plan for our first sprint, outlines our system goals, and reflects on some of the more technical (and ethical) parts of the build.

Sprint 1 – Core Monitoring Setup

The first sprint is focused on getting the basics working. That means collecting heart rate data, doing some signal processing, and visualising the results. We're using the BBC Micro:bit with a pulse sensor that we tested earlier in the semester.

We'll track three main metrics:

• BPM (Beats Per Minute)

• HRV (Heart Rate Variability)

• FFT (Fast Fourier Transform) – to break the heart signal into different frequency bands

Implementing FFT on the Micro:bit will be tricky, especially since we're using MicroPython and the hardware has limited processing power. We're still exploring whether MakeCode will give us enough control, or if we'll have to stick with Python for more flexibility.

Cloud Integration and Visualisation

Once we’ve got some decent data, we’ll push it to the cloud. The plan is:

• Log the data to a spreadsheet

• Create a simple report to share with a doctor or caretaker

• Display a live dashboard on a phone

Sprint 2 – Analog Out and Creative Use Cases

For the next sprint, we’re aiming to implement an analog output – this will allow the Micro:bit to send data to another device, like a motor or display.

We’re hoping to:

• Try more creative ideas with the data (like real-time feedback or emotional indicators)

• Brainstorm new use cases – for example, could this help with remote care or stress tracking?

Technical Challenges

There are a few hurdles we expect to face:

• Signal noise: The pulse sensor might give messy data if not placed correctly

• Battery drain: Continuous monitoring uses a lot of power

• Accuracy: We'll need to validate our readings with commercial devices where possible

The Heartbeat Connection (Experimental Feature)

One idea we're really excited about is creating a physical connection between people using heart data. The goal is to transmit one person's heartbeat to another’s Micro:bit, which triggers a vibration motor in sync. This could be used to:

• Let a loved one feel your heartbeat in real-time, even if they’re far away

• Help patients and doctors build more empathetic connections

We’ll also experiment with mapping HRV data to vibration intensity – more stressed states might feel different than calm ones.

Final Thoughts

This project mixes everything we’ve been learning: sensors, signal processing, cloud apps, and a touch of biomedical thinking. What makes it stand out is the human side – we’re not just gathering numbers, we’re trying to make that data meaningful.

There’s a lot of debugging and problem-solving ahead, especially with FFT and Micro:bit limitations, but that’s part of the learning. Hopefully by the end, we’ll not only have a working IoT system but one that can connect people in a small but powerful way.