The custom HC-01 boards are here. One photo tells the story: the new revD board sitting right above the jumper-wire prototype it replaces.

Every jumper is now a routed trace. Every module — display, environmental sensor, fan driver — gets a dedicated plug-in header. USB-C with a CH340C replaces the dev-board dongle, and the ESP32-WROOM-32E sits directly on the board. Designing it meant learning schematic capture, layout, and DFM as a company of one.

The lesson from this phase: the prototype's job is to be wrong fast. The board's job is to be right forever. You need both.

Full writeup of the jump from jumper wires to a custom PCB: https://www.byitl.com/blog/hc-01-humidor-controller-jumper-wires-to-custom-pcb

Next: bring-up on the new boards — which turned into a story of its own.