This is simply a reshare of an existing open-source project — all design credit belongs to AlexEkb, and the original lives at https://github.com/AlexEkb4ever/ZX_RGBI2VGA-HDMI under GPL-3.0. Nothing in the design has been altered; the files here have only been reorganised, documented, and prepared for fabrication.

The board captures the ZX Spectrum's four digital colour signals (R, G, B and the brightness bit) directly from the machine's ULA or logic, rather than digitising an analogue output the way commercial adapters do. A Raspberry Pi Pico handles capture and video generation, using the Z80 clock as a pixel clock and the composite sync line for timing. A 74LVC245A buffers the incoming 5 V signals down to the Pico's 3.3 V logic.

One PCB supports two mutually exclusive builds. Fit the HDMI receptacle with all eight resistors at 270 Ω, or fit the VGA socket with 100/390/820 Ω values and bridge the three solder jumpers — then flash the matching firmware. The board measures 30.48 × 68.58 mm and carries a 1×20 breakout row plus a 9-pin input header for the ZX side.

Note that the upstream repository contains no KiCad source files, only gerbers and a schematic image, so the board cannot be edited without redrawing it. The BOM and centroid in this package were reconstructed from the fabrication data and are documented accordingly.