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Backlid

Experimental iPhone accessory with a secondary rear display.

embedded Linuxcustom PCBMIPI DSIUSB-Cwireless displayhardware design

Concept

Most iPhone accessories are passive. Cases protect the phone. Battery packs extend power. MagSafe wallets add storage. Backlid explores a more active accessory category: an intelligent rear display that can show content, mirror the screen, or create new interaction patterns.

Prototype Journey

Backlid started as a Raspberry Pi-based prototype with a Waveshare touchscreen. The goal was to explore screen mirroring, touch input, and what a second-screen iPhone accessory could feel like.

The project later moved toward a custom embedded board with strict mobile constraints: limited power, thin component height, wireless connectivity, and a premium physical form factor.

Technical evolution:

  • Early Raspberry Pi prototype direction
  • AirPlay / screen mirroring exploration
  • Moved toward custom PCB design (KiCad / Flux.ai)
  • Amlogic A311D2 and Rockchip RK3566 considered as compute options
  • Long-term direction: thin custom PCB with processor, RAM, eMMC, wireless, power management, touch controller, and display interface

Constraints

Backlid is defined by its constraints because that makes it credible:

  • Thin mobile form factor (~3.5 mm component height target)
  • Limited power budget (~5–6 W)
  • Heat management
  • Touch display integration
  • Wireless + USB-C connectivity
  • Reverse wireless charging direction
  • PCB shape matching iPhone-style rounded corners
  • MagSafe coil area (55.8 mm diameter)

What Backlid Proves

The project shows the ability to work with physical product constraints, think in systems (display, power, compute, wireless, industrial design), and prototype ambitious ideas that sit between software and hardware.

Status

Experimental hardware prototype. Custom PCB exploration. Not a finished commercial product.