Ferris Sweep

A 34-key split keyboard, built from a parts list and a soldering iron.

Thirty-four keys, split in two halves, wireless, running ZMK on a pair of nice!nano controllers. The board is David Philip Barr’s Sweep design; the PCB was ordered matte black from JLCPCB, the case is printed, and the keymap is mine.

The keymap is the actual project. A 34-key board has no number row, no arrow cluster and no symbols, so every one of those has to be reached through a layer — and where they sit is a question you can only answer by typing on it for a month. The iteration list in my notes runs to sixteen changes, almost all of them struck through: brackets moved above the home row for reachability, a second shift under the space key so shift-tab stops being a contortion, hold durations tuned separately for layers and for home-row mods.

One rule survived all of it: a hold-layer key should never have keys mapped on the hand holding it. Otherwise the hand doing the holding is also doing the reaching, which is the strain the board existed to remove.