Gitzian can be used as a store-bought Kit, but it can also become a highly customized DIY project around the tiny 21×19 mm Gitzian decoder module. Custom hardware is built around the decoder; the boards around it are the part you can adapt to your own controller, display, case, and mechanical setup.

The decoder has two board-to-board connector sides. One side is the input/controller side. In the standard reference setup this is the Raspberry Pi HAT. The other side is the output/display side. For supported display setups this is usually a matching display bridge, such as the TDO Display Bridge.

The current reference setup uses two boards around the decoder because this gives more flexibility while the display side is still evolving. You can keep this split, replace only one side, or merge the input and output side into one larger custom carrier around the decoder.

For supported display setups, I publish KiCad reference designs through the Gitzian downloads page. The matching display bridge depends on the display and firmware configuration. You can also use the reference designs to create a different board with similar electrical requirements, different ICs, or a different layout.

Some signals are routed from the input connector side to the output connector side. This can be useful if you want to reuse one existing side of the design and replace only the other side. I plan to add more simple open source boards for more displays and other manufacturers over time.

If electrical details are not obvious from the reference design, let me know. The more interest there is in DIY builds, the more detailed the hardware docs will become.

I recommend getting the reference boards first before you try a full custom design. There are many details that can be changed, but the reference setup gives you a known-good starting point.

This is a highly advanced topic. I am glad to help with details around the Gitzian design, decoder wiring, or what I intended in the reference boards (contact me). I cannot provide general KiCad training or general PCB manufacturing support.

The Raspberry Pi talks to the decoder over SPI. The current Python client uses 64 MHz SPI. That is already cranked up pretty high. Lower frequencies may still work perfectly fine, depending on screen size, image complexity, and latency target.

Advanced users can replace the Raspberry Pi entirely. For example, a custom microcontroller board, Arduino-style board, ESP-based design, or another embedded controller can be built around the decoder if it implements the required hardware and protocol behavior.

The open source Gitzian Python package is the best reference implementation for this. It shows how the client side talks to the decoder, handles display output, and deals with local input and hardware features.

Python client reference: pypi.org/project/gitzian

The KiCad reference designs around the decoder are open source hardware. You can use them as a starting point, modify them, or build your own boards. If you sell boards based on the reference design, use your own product name and remove my logos from the board. Do not present your boards as produced, sold, or warranted by Gitzian.

My current preferred license direction for the KiCad files is a permissive open hardware license, with separate brand and logo rules. I want the boards to be useful for DIY and small builders, while keeping the Gitzian name clear for official hardware.

Custom hardware is a hardware-level project. Check connector orientation, power rails, signal levels, flashing access, and display wiring before plugging anything into the decoder. If you only want to use the product, use the standard Kit/reference setup from the How to page.