Chitin mod brings PIM447 trackball support to ZMK v0.3.0 firmware

KBD.news published a short post on February 24, 2026, announcing Chitin, described as a developer’s heavily modified driver that adapts an existing trackball driver (pim447 by mwandzik) to work with ZMK v0.3.0 firmware. The post frames Chitin as an integration that targets ZMK v0.3.0 specifically, signaling a concrete compatibility step for anyone running that firmware baseline.

The story follows an earlier KBD.news entry from October 4, 2021, where cdc_mkb wrote a Zephyr driver for the Pimoroni PIM447 and "added the necessary glue on top of the 'mouse' development branch." That 2021 post reports the work was "Coded, built and tested by cdc_mkb on a Zephirum" and highlights the UX tuning: "Thanks to a neat trick, small displacements are very precise whereas large displacements are quite fast; it never feels choppy at all." The 2021 author also warned of integration timing, writing, "It probably won't be merged) until the ZMK 'mouse emulation' dev. branch is stabilized."

There is a clear attribution discrepancy between the two KBD.news items. The 2021 piece credits cdc_mkb as author of a Zephyr PIM447 driver, while the 2026 Chitin post refers to "pim447 by mwandzik" as the trackball driver that Chitin adapts. The supplied material does not state whether cdc_mkb's Zephyr driver and "pim447 by mwandzik" are the same codebase, forks, or separate implementations, so both attributions are recorded without assumption.

Technical particulars from the 2021 post remain relevant to evaluating Chitin. cdc_mkb noted, "I only use the USB HID for the moment, so I have no idea on the battery impact. However there is a concern in this regard since the driver is in polling-mode so I contacted Pimoroni to get more information in order to write a new driver in interrupt-mode." The 2026 excerpt does not indicate whether Chitin addresses USB HID scope, polling-mode versus interrupt-mode, or battery-impact concerns raised in 2021. The 2026 post excerpt itself truncates after the phrase "Chitin is effectively" and provides no repository link, author credit, or code snippet in the supplied text.

Community context and related projects cited in the original KBD.news archive reinforce that trackball work sits inside a small but active niche. The 2021 page lists related projects including Ploopy by crop_octagon, Cornball by Protieusz, AWKB by wj-zhe, Kivipallur by dr3san, and a Kyria build by UghThatsTheWorst. That post also carried an audience line that reads, "Out of 150,000 readers, only 54 support this blog. Will you join Micah Alpern, FFKeebs, and @therick0996?" and site copy such as "10% off ergo caps at 3dkeycaps! Code: KBDNEWS."

Chitin’s mention of ZMK v0.3.0 gives builders a clear integration target, but the community lacks the definitive artifacts needed to evaluate impact: no Chitin repo link, no full 2026 post body in the supplied excerpt, and no statement tying the 2021 and 2026 driver attributions together. Verify authorship of "pim447 by mwandzik," obtain Chitin’s repository or patch, and confirm whether Chitin resolves polling-mode and battery concerns to determine if this mod is a straight compatibility shim or a deeper driver rewrite for PIM447 on ZMK v0.3.0.