Earbud Earrings — Final Project Milestones
This page documents the current state of my HTMAA final project: earbud earrings — a pair of wearable, jewelry-like earbuds that aim to reconcile style and everyday audio utility.
Motivation: Turning Earbuds into Earrings
Accessorizing in the modern world is a surprisingly difficult task. Like many Elle Woods fans, I dream of perfect outfit coordination; the kind where every accessory feels intentional.
But in practice, utility often gets in the way of style.
I spend my days hopping in and out of calls, tuning out the bustle of coffee shops and libraries, all thanks to my trusty earbuds. They’re indispensable — but they rarely look the part. They dangle awkwardly when not in use, clash with carefully chosen jewelry, or disappear at the bottom of a bag.
This everyday mismatch between style and function sparked an idea: what if earbuds could become earrings? Instead of treating them as an afterthought, why not design them as intentional accessories — elegant, wearable, and always at hand (or rather, ear)?
Brainstorming & Initial Concept
The initial idea was ambitious: earphone earrings that could charge themselves kinetically. The vision was to harvest energy from everyday motion — walking, turning, even dancing — and use it to power a pair of elegant wireless earbuds that double as jewelry.
It felt like the perfect marriage of fashion, technology, and a bit of sci-fi optimism.
Researching Existing Designs
Before diving into feasibility, I reviewed products and concepts that reimagine wearables and audio:
- Zhang Yunxib’s designs — playful, sculptural forms that reimagine everyday electronics.
- Yanko Design collection — alternative earbud form factors and housings.
- Nova Audio Earrings — pearl earrings that are fully functional Bluetooth earbuds.
Exploring Kinetic Charging
One of the most exciting (and challenging) ideas was kinetic energy harvesting. Building on the piezoelectric effect (first identified by Pierre and Jacques Curie in 1880), I explored whether motion could meaningfully power earbuds.
Reading & References
- Piezoelectric energy harvesting overview (ScienceDirect)
- Can we harness electricity from human movement? (Medium)
- Hybrid human-motion energy harvesting techniques (ScienceDirect)
Human movement is irregular, and most piezoelectric harvesters output on the order of microwatts — far below typical earbud power needs.
Because of this highly intermittent and low-power output, it quickly became clear that relying solely on motion-based harvesting for v1 would not be realistic. A secondary charging port (wired) is needed, with kinetic harvesting reserved as a possible augmenting feature for future versions.
Conversations with TAs: Reality Check
Anthony: “I cannot understate how hard it is going to be to get energy harvesting like this to power a pair of headphones.”
Using numbers from recent literature (best-case ≈ 67 µW harvested), Anthony estimated this to be roughly ~500× lower than what a single earbud would need. As a rough mental model, charging an AirPod-class battery via motion alone would correspond to something like ~1,500 hours of motion for one earbud — and double that for a pair — even before accounting for conversion losses.
Gert: “Scope the fundamentals first: power budget, a microcontroller with Bluetooth that won’t weigh down the ear, and sensor choices.”
Gert’s advice helped break the problem into a more manageable roadmap, and made the scope constraints clearer for a one-semester build.
Pivoting the Project
Given the constraints, I pivoted away from full kinetic self-charging for now and refocused on the core experience: earbud earrings that combine style and utility. This keeps the heart of the idea — intentional, wearable design — while making the v1 prototype feasible within HTMAA.
Next Steps (Design Process Preview)
- Form studies: 2D sketches and 3D-printed test geometries for weight, balance, and attachment comfort.
- Mechanism: magnet/clip interfaces for quick transitions between “earring mode” and “listening mode”.
- Electronics basics: evaluate MCU + BT audio options, amplifier, battery size, and wiring paths.
- Materials: experiment with resin, metal-plated finishes, and skin-safe contact surfaces; test pearlescent/metallic looks.
- Charging (v2+): leave provisions in the design (space, pads) for future hybrid charging, including experimental kinetic harvesting.
System Diagram
The project combines mechanical design, electronics, and embedded programming into a small, ear-worn form factor.
- Mechanical / 3D structure
- Earring shell (printed or cast, jewelry-like form)
- Detachable “earbud” body with driver + electronics
- Magnetic or clip attachment between earring and earbud
- Electronics
- Microcontroller / audio module (e.g. ESP32-S3 or BT audio board)
- Audio amplifier + small speaker/driver
- Battery + charging interface (wired for v1, experimental harvesting for later)
- Interaction
- Capacitive touch or button for play/pause
- LED indicator for pairing / battery status (optional)
Tasks to Be Completed
To get from concept to a working prototype, I’ve broken the project down into concrete tasks:
1. Mechanical / Industrial Design
- Refine overall form factor (earring + earbud geometry) in CAD.
- Design magnet/clip interface between “earring mode” and “listening mode”.
- Model internal clearances for PCB, battery, and wiring.
- Prototype test shells (FDM/ resin) to check weight, balance, and comfort.
2. Electronics Design & Production
- Select MCU / audio solution (e.g. ESP32-S3 + I2S amp, or BT audio module).
- Design schematic and PCB in KiCad for:
- Power (battery, charging input, regulation)
- Audio path (amp + driver)
- Controls (touch pad / button, optional LED)
- Route the board, export Gerbers, and fabricate PCBs.
- Assemble and reflow/solder components; debug basic power and audio.
3. Embedded Programming
- Bring up the MCU / module (blink, serial logging, etc.).
- Implement audio playback path from a simple source (e.g. test tone / stream).
- Add basic controls (play/pause on touch or button input).
- Log/measure approximate power consumption for reference.
4. System Integration & Packaging
- Integrate PCB and battery into the 3D-printed housing.
- Verify clearances, cable routing, and strain relief.
- Finish outer shell (sanding, coating, metallic/pearlescent finish).
- Test attachment/detachment workflow in everyday use.
5. Evaluation & Documentation
- Evaluate comfort, stability, and usability (qualitative testing).
- Measure runtime under a simple usage scenario.
- Record a 1-minute video showing conception, construction, and operation.
- Prepare the final slide and integrate everything into the HTMAA site.
Project Schedule
The schedule below is a working plan toward a fully integrated prototype. Dates are approximate and will be updated as the project progresses.
| Week / Dates | Milestones |
|---|---|
| This week (Nov 17–23) |
|
| Next week (Nov 24–30) |
|
| Following week (Dec 1–7) |
|
| Final push (Dec 8–project deadline) |
|
Instructor Meeting
Graded review meeting:
To be scheduled with the HTMAA instructors / section staff.
Agenda for the review will include:
- Walkthrough of the system diagram and overall architecture.
- Review of planned fabrication processes (2D/3D, electronics, assembly).
- Feasibility check on scope vs. timeline.
- Feedback on risks and potential simplifications.