Prototype Specification
Product and scope
Dusk Bloom is an indoor, USB-C-powered flower-shaped reading lamp approximately 300 mm tall. It illuminates one open book while translucent petals provide a separate dusk-responsive ambient glow. First deliverable: a functional filament-printed prototype, not a certified production product. No battery, wireless connectivity, moving petals, or adjustable stem.
Industrial design defaults
- Six removable frosted/translucent blush-pink PETG petals lit by warm-white LEDs. Sage-green opaque fixed curved stem and a flatter, broader pastel-pink heart-shaped base, updated at the user's request. Task-light diffuser remains uncolored.
- Starting envelopes (design targets, not verified geometry): flower diameter 140 mm; base 150 × 110 × 45 mm; overall height 300 mm. Refine head tilt and stem reach around an open book without blocking sightlines.
- Opaque PETG base and stem, hollow wiring channel, reinforced stem attachment, removable screwed underside, captive ballast and non-slip feet. Ballast mass determined by stability testing, not guessed.
- Separate petals printed individually; test coupons establish thickness and diffusion before final printing. Avoid direct LED contact with plastic.
- Pink filament transmission and perceived color require coupon testing; lowered base packaging and ballast stability require revalidation. Previous base dimensions are superseded as styling targets, not accepted dimensions.
- Recessed downward task-light diffuser with opaque shielding to prevent direct LED glare. Ambient and task optics separated.
Lighting targets
- Task light: nominal 3000 K, CRI ≥90; design goal 300–500 lux averaged over a 400 × 250 mm book area at intended placement. Target minimum/average illuminance ≥0.5. These are proposed acceptance targets, not measured performance.
- Petals: warm-white ambient channel, lower output than task lighting; diffusion should hide obvious LED hotspots.
- Separate dimmable constant-current lighting channels. Select LEDs and optics after photometric and thermal evaluation; do not equate LED lumens with illuminance at the book.
Power and electronics
- External USB-C power supply only; no mains voltage inside the enclosure. Initial budget ceiling 10 W including conversion losses, subject to optical and thermal feasibility.
- Prefer a 5 V/3 A USB-C supply with advertised-current detection and input-current limiting; do not assume every USB port supports this. Reduce brightness safely on lower-current sources. Reconsider USB Power Delivery only if validated power needs exceed this architecture.
- Base controller board: protected USB-C input, lighting drivers, small controller, ambient-light sensor, rotary encoder with push switch, and temperature monitoring. Head lighting assembly thermally coupled to a metal spreader. Wiring/connectors rated for actual current, with strain relief and service access.
- Custom board outline follows the pebble enclosure where useful; exact geometry awaits mechanical design.
Controls and firmware behavior
- Rotary knob adjusts task brightness; short press toggles task lighting. Task light is manually controlled, never activated solely by dusk sensing.
- User-selected knob styling: rounded pink heart-shaped cap on a rotary/push mechanism. Verify full rotational sweep, push clearance, finger access and sourced shaft fit; heart orientation changes with rotation.
- Long press cycles ambient Auto / On / Off; unobtrusive indication without a bright standby LED. Power-up defaults: task off, ambient Auto.
- Ambient Auto starting thresholds: enable below 30 lux, disable above 60 lux, with approximately 10 seconds filtering and a gentle fade. Tune in the assembled prototype.
- Shaded outward-facing sensor aperture on the base, isolated from internal lighting. Validate resistance to reflected lamp light; filtering alone is not a substitute for optical isolation.
- Thermal brightness reduction and fault shutdown; limits selected from verified component ratings, enclosure material data and measured temperatures. Avoid visible flicker across the dimming range.
Cooling and construction
Conduct heat from task LEDs into a metal spreader with an effective path to surrounding air; a metal plate sealed inside plastic is not sufficient by itself. Incorporate discreet ventilation and an accessible thermal interface while guarding hot surfaces. Determine spreader dimensions through thermal analysis and full-output testing. Structural stem reinforcement and ballast must tolerate head leverage and cable pulls.
Remaining validation and exit criteria
- Source verified LED, driver, USB-C, sensor, connector and heat-spreader information before detailed design. Check library availability and footprint/pinout correctness.
- Measure illuminance grid, uniformity, glare and petal hotspots at intended book placement; adjust optics or output if targets fail.
- Run thermal soak at maximum combined output until temperatures stabilize; verify junction margins, touch safety, plastic resistance to deformation, and thermal derating/shutdown.
- Verify supply-current detection, input limiting, cable voltage drop, low-power-source behavior and fault protection.
- Test dusk response under daylight, artificial light and reflective books; require no self-induced on/off cycling. Check dimming flicker and control usability.
- Print diffusion/fit coupons; validate petal retention, tolerances, stem stiffness, wiring access and assembly without damaging insulation.
- Test tip resistance, head leverage, cable pulls and captive ballast retention; resize base or reinforcement as needed.
- Review schematic and PCB rules, then test assembled prototype. Production compliance and long-term reliability remain outside first-prototype scope.
First-pass mechanical constraints
The approved v3 drawing is binding for silhouette, proportions and control layout; previous numeric envelope targets are superseded. See project-specification, Mechanical datum and first-pass allocation, for the complete manufacturing constraint record and source evidence.
- Shared datum: controller PCB top Z=0, +Y rear, -Y reader; 64×42×1.6 controller plate centered(22,-5) PROVISIONAL; Estimated top/bottom heights10/2.
- PROVISIONAL future PCB mounting holes(-6,-22),(50,-22),(-6,12),(50,12), diameter3.4; boss bearing plane Z=-1.6. Four ST2.9 self-tapping mounts and protected mounting lands.
- Low broad heart shell approximately166×122 with Z=-22..14; underside lid2.4, ordinary wall3.0, slipped stepped joint3.0 engagement. Overall height approximately300 remains target, with exact CAD envelope reported after compile.
- Front-left heart knob(-37,-12), sourced PEC11R-4215F-S0024 shaft; maximum push0.8. Rear USB4105 receptacle on provisional off-board carrier; front shaded sensor aperture; no explanatory cutaway holes.
- Hollow split stem, retained ballast, removable petals and individually placed hardware. PETG/nozzle0.4/layer0.20 PROVISIONAL; build volume UNKNOWN. LED/thermal/optics mounting and sensor/cable final envelopes remain PROVISIONAL or deferred as identified in CAD report.
Feasibility and next phase
First-pass mechanical sources and sixty placed model nodes now exist. This is an incomplete/unqualified engineering candidate, not ready-to-print release: placed height314.130 exceeds the300 target, upper component clearance is short by0.4, and attachment/retention interfaces need follow-up. See cad-assembly-report and project-specification as-built corrections for exact parts, source evidence and fit results. Electronics/firmware work in other threads is outside this mechanical report.
Concept is plausible, but book illumination within the10 W budget and safe heat rejection remain the make-or-break assumptions. First-pass CAD now exists with documented failures; electronics progress is tracked separately. Next: authorized mechanical remediation, sourced lighting/thermal interfaces, electronics and firmware completion, then physical prototype verification. Numeric defaults remain provisional, while the approved drawing remains binding for form.