125 lines
No EOL
5.3 KiB
Markdown
125 lines
No EOL
5.3 KiB
Markdown
# Case Design
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## Form Factor
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Briefcase clamshell:
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- **Canopy** — Salvaged K501U laptop lid (display, hinge, bezel). Opens upward, hinge at the bow edge.
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- **Base** — Wooden enclosure holding keyboard, SBC, power, and peripherals.
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User sits at the stern, facing the bow. See [design-decisions.md](design-decisions.md) for full nomenclature (deck/keel/bow/stern/port/starboard).
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## Dimensional Constraints
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### Canopy (Lid)
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| Dimension | Value | Source |
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|-----------|-------|--------|
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| Width | 39 cm | Measured, rounded up |
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| Height | 26 cm | Measured, rounded up |
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The lid dimension is the *outer* shell of the K501U display assembly (plastic casing + LCD panel + bezel). The glass panel itself is smaller — these are the hinge-to-edge and side-to-side mounting boundaries.
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### Base External
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Tentative, with ~5mm per-side margin beyond the lid:
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| Dimension | Value | Notes |
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|-----------|-------|-------|
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| Width | 40 cm | Lid width + margins |
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| Depth | 27 cm | Lid depth + margins |
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| Height | TBD | Depends on component stacking |
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Base height (internal depth of the wooden box) is the critical unknown. It depends on whether all internal components fit in a single Z-slice or require multiple layers.
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## Component Footprint Inventory
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Measured and estimated dimensions for everything that goes inside the base. These are 2D floorplan sizes (width × depth); height determines minimum internal clearance.
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| Component | W × D × H | Notes |
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|-----------|----------|-------|
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| TrackPoint keyboard | ~32 × 11 cm × ~1 cm | Depends on specific model, typical compact USB TrackPoint KB |
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| Orange Pi 3B | 8.5 × 5.6 cm × ~1.5 cm | With heatsink. Mount on standoffs |
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| Display controller (eDP→HDMI) | ~7 × 5 cm × ~1.5 cm | Generic board, may vary. Near hinge |
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| IP5389 power board | ~5 × 4 cm × ~0.5 cm | Thin PCB, mount near cell pack |
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| 18650 cells ×6 (3S2P) | 19.5 × 3.6 cm × 1.85 cm | Each cell 18×65mm. 3 cells end-to-end = 195mm, 2 cells side-by-side = 36mm |
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| USB hub PCB (decased, 10-port) | ~12 × 5 cm × ~1.5 cm | Estimate — depends on specific hub |
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| HDMI A/B switch (mechanical) | ~5 × 3 × 2 cm | Passive toggle. Near hinge |
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| PAM8403 audio amp | ~2.4 × 2.1 × 0.5 cm | Tiny, anywhere |
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| Speakers ×2 | ~3.1 × 7 cm × ~1.5 cm | Small drivers |
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| Cooling fan(s) | 4–8 cm square × ~1 cm | Size TBD based on thermal needs |
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| 5A fuse + holder | ~2 × 2 × 1 cm | Inline on power rail |
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## Floorplan Strategy
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The deck surface has two fixed-location items:
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1. **Keyboard** — centered, user-facing (stern edge). ~32 cm wide leaves ~4 cm per side within a 40 cm base width for misc ports or switches.
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2. **Hinge mount** — along the full bow edge, structural.
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Everything else floats between them. The major volume items:
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- **Battery pack (19.5 × 3.6 cm)** — longest rigid item other than the keyboard. Placement candidates:
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- Behind the keyboard (between keyboard rear and hinge area) — requires ~20 cm of unobstructed depth behind the keyboard
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- Along port or starboard side — uses the 4 cm gutter on one side
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- Under the keyboard — possible if keyboard is a flat membrane type, unlikely for a mechanical
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- **OPi 3B + USB hub** — moderate footprint, flexible placement. Could sit in the area behind the keyboard alongside the battery pack.
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- **Display controller + HDMI switch** — short HDMI cable runs dictate they live near the hinge.
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### Depth Dimensions (Front-to-Back)
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```
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Bow edge (back)
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│
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[hinge area — 2-3 cm]
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[display controller / HDMI switch]
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[battery pack and/or SBC/hub zone]
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[keyboard — 11 cm]
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[palm rest area — 5-8 cm]
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│
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Stern edge (front)
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```
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Total: roughly 18-22 cm front-to-back for keyboard + palm rest, plus 15-20 cm behind keyboard for electronics. That fits within a ~27 cm base depth with room to spare.
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### Port-Starboard Layout (Width)
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```
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Port edge (left) Starboard edge (right)
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│ │
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[2 cm gutter] [keyboard ~32 cm] [2 cm gutter]
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```
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The gutters can hold the vertical battery pack, side-mounted ports, or switch cutouts.
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## Z-Stack (Depth/Layer Planning)
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**Goal: single-slice layout** — all boards and components mounted on the same plane (the keel), with nothing stacked above or below.
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Feasibility check:
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- Tallest component: speakers at ~1.5 cm, OPi with heatsink at ~1.5 cm, HDMI switch at ~2 cm
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- Battery pack at 1.85 cm
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- Leave ~5 mm clearance above tallest item → internal clearance of ~2.5 cm
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- Wood base walls at ~1 cm each → total case height ~4.5 cm
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This keeps the case within briefcase norms (~8-13 cm is the typical range, but thinner is fine) and avoids the weight and complexity of a second deck layer.
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## Open Questions
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- [ ] Exact TrackPoint keyboard model — dimensions and mounting method
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- [ ] Battery pack placement — behind keyboard vs side gutter
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- [ ] Fan size and placement — SBC heatsink fan vs case fan
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- [ ] Lid latch mechanism — holds canopy closed in transit
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- [ ] Hinge reattachment — how to mount K501U hinge to wooden base
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- [ ] Cable routing paths — power, HDMI, USB within the case
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- [ ] SD card reader location — stern edge per port layout
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- [ ] Kensington lock slot — stern edge
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- [ ] Wood thickness and joinery method
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## Revision History
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| Date | Change |
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|------|--------|
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| 2026-06-03 | Initial — dimensional constraints and floorplan approach | |