The Circuit Board Was Designed by AI: An Experiment with Fable 5 and KiCad

The author had long wanted to build a simple printed circuit board, but kept putting it off. His first attempt to “generate” a design with Claude Opus 4.8 ended in failure: the model couldn't grasp component orientation and couldn't handle the routing. Frustrated, he came back to the idea later — this time with the Fable 5 model.

The Rules of the Experiment

The author set himself two conditions: no manual edits or checks of the board, and any problem before sending it off to production had to be solved by Fable alone. In effect, he entrusted the neural network with his wallet and acted merely as the client. In a short prompt he described a development board based on the RP2350, capable of driving an E-ink display. After working autonomously for a couple of hours, the model produced a finished project: a board measuring 31.8 × 37.32 mm with four layers, an RP2350A microcontroller, a 1.54" display (200×200), and 8 MB of QSPI flash memory.

Where the AI Got It Wrong

It wasn't flawless. A colleague of the author's, once he'd recovered from the sight of the layout, first asked him to check for DRC errors — there turned out to be 65 of them. By the rules of the experiment, the author only reported the problems to the model. Fable did an excellent job picking the components, but twice missed on the footprints: for the W25Q128JVS flash memory it drew pads for a smaller package, while the transistor, conversely, turned out too small for its pads. In the end, the flash was replaced with a P25Q64SH.

The routing was a story of its own. At first the model used the open-source Freerouting project: it churned away for two minutes, made seventeen passes, and got stuck, leaving 49 traces unconnected — the remainder Claude routed by hand. Later someone pointed the author to a tool called KiCadRoutingTools, which completed all the connections in 1.25 seconds.

The Board Arrived

Ordering five assembled boards from JLCPCB cost 130 euros; the author praises the service for its simplicity. The first thing he did was check for a short circuit between 3.3 V and ground (his colleague suggested just risking it) — there was no short. The board was recognized on connection and worked: the author wrote a clock, a stopwatch, a reader for .txt files from the flash memory, and an image album that, thanks to E-ink, stays on the screen even after power-off.

Mixed Feelings

The author's verdict is ambivalent. On the one hand, it's thrilling to be able to describe a board in plain language and receive a working device a couple of days later, knowing nothing about design. On the other, the sense of achievement is gone: the joy used to come precisely from the learning and from overcoming difficulties. At work he still checks everything meticulously, but in his hobby he intends to keep going full throttle. The author's dream is for board manufacturers to open a chat where you could toss in ideas and sketches, and two days later receive a finished product. The next project is already underway: a tablet built on the NVIDIA Jetson Orin Nano, designed by Fable 5.1.

Source: Lobsters