Maker and tinkerer Sam Hocevar has put a Raspberry Pi Pico under the microscope for a little reverse-engineering — in order to design his own RP2040 board that swaps out the micro-USB port for a more modern USB Type-C.
"I really wanted a [USB] Type-C connector on my [Raspberry Pi] Pico H," Hocevar explains of the project's inspiration, "and I wanted it even more when I found out that the device was released less than five years ago and it still had a micro-USB port on it. I understand that one of the main draws of the Pico is that it's $4, and I am confident enough that the cost difference between Micro and Type-C would also lead to a noticeable price increase."
To scratch the USB Type-C itch, Hocevar set about designing his own Raspberry Pi Pico variant. "Raspberry Pi […] publishes lots of information on this board, including the full schematics and board layout files," the maker writes of the original Raspberry Pi Pico. "However, they're made in Cadence Allegro, and that costs a crisp $1,500/month that I do not have.
"Originally, I just made a PCB that jumped the micro-USB signals to a Type-C breakout board, but the tolerances were really tight, and it didn't look like much of a finished product," Hocevar continues. "My boss gave me the idea of just remaking the whole board and adding a Type-C port to it, so that's what I did."
Using Raspberry Pi's publicly-released schematic and PCB design files, plus a third-party bill of materials (BOM), Hocevar was able to recreate the design in KiCad — using mechanical layout diagrams for the original Raspberry Pi Pico to ensure the new variant should be a drop-in replacement for any project.
"It's okay for my needs," Hocevar says of the result, "but it's far from the actual Pico. The original one uses copper pours very strategically and has great routing, but the routing on mine is atrocious. The DRC [Design Rules Check] also gives this board 41 errors and 13 warnings, but I simply elected to ignore them. I would happily accept pull requests to improve this design."
The resulting KiCad design files for what Hocevar calls "project-piCo" are available on GitHub under the extremely permissive WTF Public License 2; additional information is available in Hocevar's Reddit post.