Heartbeat & Hue: Turning an Old Garmin into a Pulse-Reactive Bracelet

28 Dec, 2025

That is quite a long title, but it describes exactly what this project is all about. It’s a merger of my favorite interest areas: electronics, aesthetics/art, and dance.

The Components

I’m starting with a mix of salvaged parts and new components to bring this to life:

The Base: An old metal bracelet with a split-top design. It originally held a crystal that fell out, leaving a perfect gap for electronics.
The Light: A handful of old LEDs.
The Sensor: An old Garmin Heart Rate Monitor (chest strap).
The Logic: Transistors, capacitors, and a few affordable ICs (Integrated Circuits) to be ordered.
The Aesthetic: Crystals from a couple of old broken bracelets to diffuse the light.

How It Works: The Engineering Behind the Glow

The goal is to turn a wireless heart rate signal into a visible pulse. Here is the technical roadmap:

Signal Acquisition: The Garmin chest strap emits a radio signal. Assuming it’s an older ANT+ or standard radio signal rather than Bluetooth, I’ll need a tiny receiver mounted on the bracelet.
Power: The receiver and logic will be powered by tiny button batteries.
The "Pulse" Logic: Because a heart rate signal is just a quick "blip," an LED flash might be too fast to see clearly. I’m designing a circuit with a capacitor to gradually release charge, creating a "fade-out" effect that makes the heartbeat visible.
The Array: I’ll be using 4 LEDs spaced between the crystals for a diffused, glowing effect.

The Build Plan

The next step is to move from theory to reality:

Phase 1: Breadboarding. I’ll assemble the electronics on a breadboard first to ensure the receiver can reliably catch the signal from the Garmin strap.
Phase 2: Assembly. Once tested, I’ll fit the components directly into the gaps of the metal bracelet.
Phase 3: Finishing. I'll wire everything up, set the crystal stones in place, and glue them down to protect the circuitry.

Note on Power: If the button batteries don't provide enough juice, I have a backup plan for an optional external battery pack mounted on a belt.

Why Salsa?

I plan to wear this bracelet out salsa dancing. I’ve often felt my heart sync up with specific rhythms, and having a visual indicator of that physiological response—blending with the crystals and the movement—will be incredibly cool. It’s a literal representation of the music getting into your blood.