The takeaway: Custom keyboard builders can swap out switches, keycaps, plates, and firmware these days, but the layout is usually locked in once the PCB is made. Now, a new open-source project called Keybytes is trying to get around that limitation by giving each key its own tiny circuit board and microcontroller. The keys snap together with magnets and connect to a small hub, allowing a keyboard to start out as a single key and grow into pretty much any shape.
The project comes from Nathan Alspaugh, an MIT freshman studying aerospace engineering, who said he has spent around 100 hours working on it since March. When he posted the project to Hacker News this week, he said the idea came from his frustration that nobody sold triangle- or circle-shaped keyboards.
Each key, called a Keybit, consists of a 19.05mm-square circuit board fitted with a Cherry MX switch and an inexpensive CH32V003 RISC-V chip. The neighboring module, whether another key or the hub, receives power and I2C data through spring-loaded pogo pins along all four edges.
The hub, called the Keyword, occupies the same 1u footprint but stacks two PCBs. An STM32WB55 on the upper board handles Bluetooth and stores firmware for every key. Meanwhile, the lower board houses the charging circuitry for an optional LiPo battery and the USB-C port.
Rather than sharing a single bus, each Keybit bit-bangs a separate I2C connection along each of its four sides. Alspaugh explained in the Hacker News thread that this approach reduces parasitic capacitance and allows the software to determine the physical position of each key. In theory, that means a chain of keys could extend indefinitely.
Getting the magnets right took considerably more trial and error. According to his build journal, the first magnetic cases couldn't hold the modules together against the force exerted by the pogo pins. Rather than redesigning the boards to accommodate weaker pins, Alspaugh opted for stronger magnets and printed case after case in resin at a makerspace. The hub's case alone went through 12 iterations. His first working build finally came together on October 24.
Even so, the current demo features just two keys attached to the hub, as Alspaugh is still building additional modules and finishing the firmware. Layout options are also limited to a flat grid for now.
Scaling up would get expensive quickly, too. Alspaugh estimates that a fully assembled, full-size keyboard with two hubs and roughly 110 keys would cost around $900. Almost half that amount would go toward the pogo pins, so he plans to buy and solder them himself if he ever builds one.
Anyone who wants to try the project can find the schematics, case STEP files, and bill of materials on its GitHub page, which is published under an MIT license. The PCB design files are available there, too – something Keychron held back when it opened up its case and plate designs earlier this year.