Luce — Combining Form and Function for Gracious Telepresence and TeleAbsence

For HCDE 539 Physical Computing at the University of Washington, students were asked to conceive and build an original physical computing project — combining hardware, software, and meaningful interaction into a functional artifact.

I was drawn to a question that felt both personal and design-rich: how can physical objects communicate presence and absence across distance without the intrusiveness of conventional digital communication? Friends, family members, and loved ones living apart often want a subtle sense of connection — not a ping, not a call, but something quieter and more ambient.

Two objects inspired the form: the geometric folds of Bao Bao Issey Miyake bags, whose triangular panels shift and transform as the bag opens, and the Lumio Book Lamp, which collapses into the form of a book and unfolds into a lamp. Together, they suggested a design direction where the act of opening something familiar could carry social meaning. Underpinning this was the vision of TeleAbsence — the idea that a connected object could communicate not just presence but meaningful absence across distance, so that two people separated by space could still share a moment of synchronised awareness through something physical.

I proposed Luce — a connected book lamp that would transform the simple gesture of opening a book into a dual signal of presence and absence: switching on the lamp's interior light while simultaneously broadcasting that action via Bluetooth, so a paired device elsewhere could mirror the same illumination — turning two distant objects into one shared, synchronised moment of light.

As a solo project, I was responsible for the full design and development of Luce — spanning physical fabrication, electronics, and firmware:

• Design and fabricate the book lamp exterior and interior structure using laser cutting and craft materials
• Build the sensing, actuation, and communication system — reed switch, ESP32, RGB LED, and Bluetooth Low Energy
• Write firmware that detects the lamp's open/closed state, controls illumination, and transmits status wirelessly
• Achieve a fully standalone system, powered independently without a laptop, within the compact form factor of a book lamp

The constraints were demanding: a compact form factor meant every component had to be placed deliberately, the circuit had to be shallow enough to allow the book to close, and the power supply had to be reliable without exceeding the lamp's physical dimensions. All of this had to be figured out from scratch — I came into this project with zero prior knowledge in fabrication.

Iterated on the switch design from mechanical to reed switch

Motivation The core interaction of Luce — opening the book to signal presence — depended entirely on a reliable sensor that could detect the book's open or closed state. The choice of switch directly determined whether the system would feel seamless or frustrating to use.

Action The switch design went through two rounds of iteration:

1. Design 1 — Mechanical switch (paper + conductive tape): A mechanical switch was constructed from paper and conductive tape, designed to physically open or close the circuit depending on the opening or closing of the book lamp
2. Design 2 — Reed switch sensor: A reed switch was embedded in the lamp and paired with a small magnet on the opposing book cover. The reed switch was connected to one of the ESP32's GPIO pins, configured with an internal pull-up resistor. When the book is closed, the magnet brings the reed switch close, closing the circuit and pulling the GPIO pin to ground. When the book opens and the magnet moves away, the GPIO pin is internally pulled back to high — cleanly signalling the lamp's open or closed state to the ESP32

Design 1 — Mechanical slider switch

Design 2 — Reed switch sensor ★ Final design

Challenge The mechanical switch, while conceptually simple, proved unreliable in practice — the conductive tape contacts were inconsistent, and the switch's physical construction was incompatible with the ESP32's GPIO logic levels, making it impossible to use as a reliable digital input.

Solution Switching to a reed switch resolved both issues simultaneously. The reed switch is a solid-state sensor with no moving parts that can wear out, and its binary open/closed output mapped cleanly onto the ESP32's internal pull-up GPIO logic — no external circuitry required. The magnet-based activation also meant the sensor could be embedded entirely out of sight inside the lamp's structure, preserving the clean aesthetic of the exterior.

Solved standalone power through 4 rounds of iteration

Motivation A connected keepsake tethered to a laptop would undermine the very premise of Luce — it needed to be portable and self-contained, placed wherever a user kept meaningful objects in their home. Achieving standalone power was non-negotiable, but each candidate power source introduced trade-offs between voltage, size, and fit within the compact book form factor.

Action Systematically tested four distinct power supply designs in sequence, evaluating each against three criteria: whether it could reliably power the ESP32, whether it fit within the lamp's physical dimensions, and whether it was practical for everyday use.

1. Design 1 — 1.5V coin battery: Too low a voltage to reliably drive the ESP32; insufficient even with multiple cells in series
2. Design 2 — 3V 2×AA battery pack: Better voltage but still unstable under the ESP32's peak current draw during BLE advertising
3. Design 3 — 3.7V LiPo battery pack: Sufficient voltage but the battery's physical profile was too tall to allow the book lamp to close properly
4. Design 4 — 5V portable power bank: Provided clean, regulated 5V power, a low enough profile to fit within the lamp's interior, and sufficient capacity for extended use — chosen as the final design

Design 1 — 1.5V coin battery

Design 2 — 3V 2×AA battery pack

Design 3 — 3.7V LiPo battery pack

Design 4 — 5V portable power bank ★ Final design

Challenge Each power source that was physically small enough tended to lack the voltage or current stability the ESP32 needed, while sources with reliable electrical characteristics were physically too large. The constraints of form and function were in direct tension with each other throughout this phase.

Solution Rather than treating the power source as a fixed given, I treated it as a design variable on equal footing with the physical form — iterating on both simultaneously. The portable power bank was the resolution point: it offered regulated power at the right voltage and happened to exist in a form factor slim enough to fit inside the lamp interior. Throughout this process, I consulted regularly with the course instructor and TA, who not only helped me troubleshoot power constraints but also introduced me to advanced fabrication methods I had no prior exposure to — such as kerf patterns for creating living hinges in rigid materials, which directly informed the hinge design iterations in the next phase of the project.

Balanced form and function across the compact book lamp structure

Motivation Luce's identity was inseparable from its physical form — it needed to convincingly read as a book when closed, and as a lamp when open. But the same compact form factor that made the object beautiful imposed strict constraints on the circuit design: components had to be placed frugally, and the overall circuit height had to be minimised so the book could close fully.

Action

1. Exterior — wood vs. cardboard: Laser-cut the same geometric pattern into both wood and cardboard to compare material suitability. Wood was chosen for its rigidity and the clean definition it gave the triangular facets; cardboard was too brittle along the cut edges to bend without cracking
2. Hinge — kerf patterns vs. cardboard interior: Tested multiple wooden kerf patterns as living hinges between the two exterior panels. All had too high a bend radius, preventing the book from opening and closing smoothly. Replaced with a flexible cardboard interior, which provided the necessary malleability while holding its shape
3. Fold design: Explored different paper folding configurations using A3 sheets to find the geometry that best balanced interior volume (for electronics) with exterior silhouette
4. Circuit layout: Arranged all components — ESP32, reed switch, RGB LED, and power bank — to minimise stack height, routing wires flat against the interior surface and positioning the power bank horizontally to keep the profile as low as possible

Exterior Design Iterations

Design 1 — Solid triangles

Design 2 — Cardboard triangular cuts

Design 3 — Wooden exterior ★ Final design

Hinge Design Iterations

Design 1 — Six kerf patterns (too rigid)

Design 2 — Cardboard interior ★ Final design

Fold Design Iterations

Design 1 — One fold, open bottom

Design 2 — Two closed folds

Design 3 — Two 90° folds ★ Final design

Challenge Every design decision about the physical form had a downstream consequence for the electronics, and vice versa. Choosing a thicker material or a different fold configuration could mean a component no longer fit, or the book could no longer close. The mutual constraint between form and function meant no decision could be made in isolation.

Solution I treated form and function as co-evolving constraints rather than sequential design phases — making small changes to one and immediately testing the impact on the other. This iterative loop, repeated across exterior, hinge, fold, and circuit layout, was what eventually converged on a final design that satisfied both: a lamp that closed cleanly, opened gracefully, and housed a fully functional electronics system within its interior.

"A standout project! The concept of using ambient light and a physical book-opening gesture to signal presence across distance is both poetic and original, and the laser-cut enclosure is beautifully executed."

— Garrett Miller, Instructor of HCDE 539 Physical Computing · Director of Experience Design, Customer Success Experiences @ Autodesk

Through this project, I strengthened my ability to:

• Design under mutual constraint — where form decisions directly affect electronics, and vice versa — requiring iterative co-evolution rather than sequential design
• Physical fabrication skills including laser cutting and 3D printing — the latter explored with PrusaSlicer in earlier design iterations not documented here — all self-taught from zero prior fabrication experience
• Treat technical variables (power supply, component placement, circuit architecture) as design variables on equal footing with aesthetic ones
• Embed social meaning into the form and interaction of physical objects, rather than relying on screens or digital notifications to carry the communicative weight
• Build standalone, wireless embedded systems from scratch — covering hardware fabrication, firmware development, and Bluetooth communication