cyberdeck/docs/sbc-selection.md
BarnacleBoy 3c11190822 update all docs: Orange Pi 3B 8GB purchased (89)
- 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
2026-05-24 06:51:26 +00:00

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SBC: Orange Pi 3B

Purchased: Orange Pi 3B 8GB, with 256GB eMMC module Cost: $189.00 (incl. tax and shipping) CPU: Rockchip RK3566 (quad Cortex-A55 @ 1.8GHz, 22nm)


Specifications

SoC: Rockchip RK3566

Attribute Value
CPU 4× Cortex-A55 @ 1.8GHz
GPU Mali-G52 2EE
NPU 0.8 TOPS AI accelerator
Process 22nm

Memory

Attribute Value
RAM 8GB LPDDR4/LPDDR4X
Onboard storage 256GB eMMC module

Storage Options

Interface Speed Notes
eMMC (onboard) ~300 MB/s read Primary boot. 256GB module installed.
MicroSD Up to 512GB Backup/expansion
M.2 M-key PCIe 2.0 x1 (~300 MB/s) or SATA III NVMe or SATA SSD

Connectivity

Port Count Speed / Spec Notes
USB 3.0 2 5 Gbps Two native USB 3.0 ports (vs 1 on OPi5)
USB 2.0 2 480 Mbps
USB-C 1 Power only (5V input)
Ethernet 1 Gigabit (RTL8211F)
HDMI 1 2.0, 4K60
eDP 1 Native eDP Direct panel connection possible
MIPI DSI 1 Display
MIPI CSI 1 Camera
GPIO 26-pin I2C, SPI, UART, PWM
WiFi Built-in WiFi 5 (802.11ac) No USB dongle needed
Bluetooth Built-in BT 5.0 with BLE

Power

Attribute Value
Input 5V USB-C only
Current 3A recommended
Typical draw 3-5W under load

Much more power-efficient than OPi5 (~8W) — battery lasts longer, less heat.


Why This Board

What Changed From OPi5

The original plan was an Orange Pi 5 16GB (~$104). This OPi 3B is a different class:

Comparison OPi 3B (purchased) OPi 5 (planned)
CPU 4× A55 @ 1.8GHz 4× A76 + 4× A55
RAM 8GB 16GB
Storage 256GB eMMC onboard MicroSD only
WiFi Built-in None (needed dongle)
USB 3.0 2 ports 1 port
eDP Native port None (HDMI only)
Power draw ~3-5W ~8W
Cost $189 $104

Tradeoffs:

  • Less CPU performance and half the RAM, but 256GB onboard eMMC and built-in WiFi eliminate two separate purchases
  • Native eDP port may replace the external controller board (~$24 savings, pending cable compatibility)
  • Lower power draw means simpler battery system
  • Higher upfront cost ($189 vs $104) but includes eMMC and WiFi that the OPi5 would have required buying separately

Why Still the Right Pick

  1. 256GB eMMC is huge — No SD card for boot needed. OS + apps + projects fit onboard.
  2. Built-in WiFi+BT — No USB dongle, no antenna wiring, one less thing to buy.
  3. 2× USB 3.0 native — More bandwidth for peripherals without hub contention.
  4. Native eDP port — If cable/adapter works with the N156HGE-EAB panel, the external controller board isn't needed.
  5. Lower power — 3-5W means the IP5389 battery system can be smaller/lighter.
  6. M.2 M-key — Can add an NVMe or SATA SSD for bulk storage if needed.

Accessories Included With Purchase

The $189 purchase is the board with 256GB eMMC module pre-installed. Still needed:

Item Cost Notes
USB-C power supply (5V/3A) ~$8-12 For initial testing before battery integration
Heatsink TBD RK3566 at 1.8GHz needs passive or active cooling

Resources