Mechanical Lightboard Assembly Design Spec - thepinkmile/Enigma-NG GitHub Wiki

Lightboard Assembly โ€” Mechanical Design Specification

Status: Draft Project: Enigma-NG Author: Izzyonstage & GitHub Copilot Version: v0.1.0 Associated Hardware Revision: Rev A Last Updated: 2026-04-20

1. Overview

A standalone indicator lightboard assembly that mirrors the operator-facing HID character layout. This assembly contains the lightboard panel, the lamp / indicator harness, and one Encoder Module populated/programmed in the LBD_DEC role.

The lightboard assembly is electrically independent of the keyboard assembly. It connects to the Stator through its own 26-pin IDC ribbon on the dedicated LBD_DEC port.

2. Indicator Layout

The lightboard mirrors the same 40-position physical layout used by the keyboard assembly.

  • Printable indicator positions (ร—38): [a-z0-9+=].
  • Alphabetic case handling: uppercase alphabetic outputs illuminate the matching alphabetic indicator position rather than a separate uppercase-only physical position.
  • Layout pairing: keyboard and lightboard panel geometry should remain visually aligned so the illuminated output corresponds to the operator's expected key position.

For the character-space mapping and decode behaviour, see design/Electronics/Encoder/Design_Spec.md ยง6 Key Mapping.

3. Encoder Allocation

The lightboard assembly uses one generic Encoder Module in decode service:

  • Stator drives ENC_IN[0:5] into the LBD_DEC board.
  • The board asserts one of up to 64 output lines.
  • Initial Rev A implementations may populate only the 26- or 40-position lightboard subset, while the board footprint retains the full 64-line capability for future layouts.

4. Service / Packaging Intent

  • The lightboard is its own serviceable assembly and must be removable without disturbing the keyboard assembly.
  • Harnessing should preserve direct one-to-one mapping between populated indicator positions and the assigned Encoder output terminals.
  • The assembly split is intentional so keyboard and lightboard packaging can evolve independently.

5. Cross-References

Document Description
design/Electronics/Encoder/Design_Spec.md Generic Encoder Module pinout and decode-role definition
design/Mechanical/Keyboard_Assembly/Design_Spec.md Matched keyboard assembly using the same logical layout