Open Hardware Files: Retro Sound, E-Paper Timing, and an STM32 Board

A pair of classic sound chips, a quiet e-paper timer, and a well-connected microcontroller board make an interesting set of designs to explore this weekend. These picks come from our November 7, 2026 open-hardware file review. Each has editable KiCad source, rather than just a PDF schematic or Gerber package.

We checked the source files and licensing, but have not built or electrically tested these boards. The links below point to the reviewed revisions so you can inspect what was available at the time.

RC2014 Turbo Sound: two sound chips for a retro bus

RC2014 Turbo Sound schematic, rasterized from the published design PDF. © 2025–2026 r0b0t1cu, CERN-OHL-P-2.0. Design illustration, not a tested build.

The RC2014 Turbo Sound project by r0b0t1cu brings dual AY/YM stereo sound to an RC2014 or RC bus system. Hardware release material published on November 7 includes the editable design, jumper information, and manufacturing files.

For a retrocomputing builder, the appeal is being able to follow the whole path from bus connections to the sound circuitry, then adapt the board to a particular system. The project includes KiCad 10 schematics and a two-layer PCB under CERN-OHL-P-2.0. Assembly photographs are available upstream, but we have not independently verified audio playback, compatibility, or manufacturing quality.

Project introduction | Editable engineering files | Hardware license

ocn-ePaper: a small timer with a visible revision trail

ocn-ePaper PCB render from the project repository. © 2026 Andy Miller, CERN-OHL-P-2.0. Not a photograph; the render’s exact hardware revision is not independently identified.

z2amiller’s ocn-ePaper combines an MSP430 and a 2.13-inch e-paper display in a magnet-controlled elapsed-time counter. Its rev 0.3 PCB and manufacturing outputs were updated on November 7 in Pacific time (November 8 UTC).

The repository contains KiCad 10 schematics and a two-layer PCB under CERN-OHL-P-2.0. There is an important documentation wrinkle: the README still describes rev 0.1 and says the board has not yet been made. Treat this as a work in progress, and check the source revision before relying on older battery or runtime claims. We have not verified power consumption or display behavior.

Project introduction | Schematic source | PCB source | Hardware license

STM32G0 development board: connectivity on one PCB

STM32G0 board top-level schematic, rasterized from the published design PDF. © 2026 Stepan Filimonov, CERN-OHL-P-2.0. Prototype design; not independently tested.

khosta77’s STM32G0 development board combines a W5500 Ethernet interface, USB-to-UART, storage, and Arduino-style expansion. November 7 changes included PCB refinements and the addition of licensing and manufacturing documentation.

The editable files use KiCad 10, with hierarchical schematics and a four-layer PCB. Original hardware is licensed under CERN-OHL-P-2.0; third-party libraries retain their own terms. The author reports passing ERC and DRC, but also states that the board has not yet been fabricated and tested. Before ordering boards, review the layer stack and impedance requirements, and finish the component sourcing details.

Project introduction | Main schematic | Schematic sheets | PCB source | Hardware license

Start with the files, then do the checks

Open design files make it easier to understand a circuit, propose a change, or plan a small run. They do not replace electrical testing, sourcing checks, or compliance work. Open the linked revision, read its license and build notes, and verify the design for your own use before manufacturing.

source https://blog.tindie.com/2026/11/open-hardware-files-retro-sound-e-paper-timing-and-an-stm32-board/