BarnacleBoy
3c11190822
- docs/sbc-selection.md: full rewrite for OPi 3B specs (RK3566, 8GB, 256GB eMMC, built-in WiFi) - README.md: SBC description, checklist, components table, quick ref, cost estimate - docs/parts-list.md: SBC marked purchased, eMMC/controller/WiFi changes - docs/design-decisions.md: WiFi exclusion reason, native eDP, power input - docs/salvage-analysis.md: WiFi card not needed, cooling fan, summary tables - docs/storage-architecture.md: rewritten for 256GB eMMC primary boot - docs/usb-expansion.md: 2x USB3 native, port allocation, power budget - docs/port-layout.md: OPi3B port differences (eDP, power-only USB-C, built-in WiFi) - docs/power-system.md: lower power draw context
2.9 KiB
Design Decisions
Build Approach
Wooden case with salvaged laptop lid (screen + hinge) as the canopy. Approximate briefcase dimensions, with the display panel setting minimum width and depth.
Salvage Exclusions
- Webcam: Scrapped. Proprietary pinout, not worth reverse engineering.
- Keyboard/trackpad: Proprietary connectors, not reusable.
- RAM: DDR3L soldered, wrong generation.
- SSD: Owner repurposed.
- WiFi card: Intel 7265NGW — OPi3B has built-in WiFi+BT, no external card needed.
Case Orientation & Nomenclature
User sits at the stern, facing the bow. Hinge axis runs port-to-starboard along the bow edge.
Base (wooden enclosure)
| Term | Surface | Notes |
|---|---|---|
| Deck | Top | Keyboard, controls, SBC access |
| Keel | Bottom | Sits on table |
| Bow | Back edge (spine side) | Power input, heat exhaust, farthest from user |
| Stern | Front edge (lip side) | User-facing, keyboard near here |
| Port | Left (facing bow) | |
| Starboard | Right (facing bow) |
Canopy (laptop lid + screen)
| Term | Surface |
|---|---|
| Canopy dorsal | Outside of lid |
| Canopy ventral | Screen side |
Bow Wall Functions
- Power input (5V USB-C for charging)
- Exhaust fans blowing away from user
- Heat management surface
Carry Handle
Stern edge (lip). Screen is lightweight, hinge is rigid, and a lid latch is planned — so the canopy-open-under-gravity concern is handled. Keeps the bow wall dedicated to power input and exhaust.
Power System
IP5389 power bank board (preliminary). All-in-one: charging, BMS, USB-C PD output. See power-system.md for details.
Display Connection
The Orange Pi 3B has a native eDP port in addition to HDMI. This means:
- The Innolux N156HGE-EAB panel (30-pin eDP) may connect directly — bypassing the external controller board
- Needs verification: the OPi3B's eDP connector type and pinout must match the panel
- If compatible, saves ~$24 and eliminates an external component
- If not, fallback is the eDP-to-HDMI controller board (already ordered)
See sbc-selection.md for eDP compatibility notes.
Video Output
Mechanical HDMI A/B switch (passive, no power). Routes OPi3B's single HDMI to either the internal display (via eDP or eDP-to-HDMI controller) or a panel-mount HDMI jack on the starboard side. DisplayLink doesn't work on ARM — no drivers exist. Dual simultaneous display is not possible on the OPi3B (single HDMI output).
Input Device
ThinkPad TrackPoint keyboard (specific model TBD based on availability). Chosen for built-in TrackPoint pointer and 15.6" deck space compatibility.
Carry Handle
Stern edge (lip). Screen is lightweight, hinge is rigid, and a lid latch is planned — so the canopy-open-under-gravity concern is handled. Keeps the bow wall dedicated to power input and exhaust.