How Hidden Magnets and a Raspberry Pi Make a Hand-Free Ouija Board Respond

The inspiration for this Halloween-oriented build came from video clips of magnetic pieces moving under a chessboard. The resulting project redirects that trick to a hand-free Ouija board that can spell messages without hands, combining a compact XY motion frame, a decorated plywood cabinet, and a reclaimed single-board computer.

Core mechanics and the board enclosure

The first stage was the motion frame. The builder's husband supplied the lightweight core XY CNC machine, completing an initial assembly within a couple of days from 3D-printed parts, fishing line, several motors, and an ESB32 that was already available.

That experiment worked well enough to influence a later, slightly beefier XY version that became the basis for a CNC plasma cutter.

The housing was a wooden enclosure made from plywood and moulding. After it was built, the builder decorated it with a little wood stain and gold spray paint, pushing its appearance toward the golden age of Spiritualism.

Only the area the planchette could reach received a letter stencil. The remaining surface stayed blank because axes and electronics occupied the interior underneath, so those gaps were painted with flower and skull motifs.

Improving magnetic coupling under friction

The mechanical challenge was not simply generating motion, but keeping grip through friction. The planchette was a fairly heavy piece of wood with a large surface area, so the magnet underneath had to pull strongly enough across the board surface. Extra magnets were added to the planchette and the CNC head. Springs were installed in the sub-board magnet mount to keep the magnets pressed against the underside without gaps. The decisive adjustment was embedding free-spinning ball bearings in the planchette's bottom so the planchette could run on them.

Software, networking, and G-code control

The control computer was a Raspberry Pi 3 Model B+ that had faithfully served as a print server for many years and had recently been freed up. Using that Raspberry Pi as the ghost in the machine felt like a fitting second life, or afterlife, for the hardware.

Raspberry Pi Imager installed Raspberry Pi OS Trixie. During the same setup, Raspberry Pi Connect was configured. That step mattered because the Ouija board was intended to move from network to network, changing its IP address each time. To reach the web UI, the current address had to be found, and Raspberry Pi Connect allowed logging in to the Raspberry Pi whenever it was online to discover it.

The application was built as a Python Flask project. When words are typed into the web UI, they are converted into G-code instructions matched to the letter positions, then sent directly through the USB serial port to the ESB32, which drives the motors. The builder's husband handled that task and delegated it to ChatGPT Codex.

The coordinate table took the most time: mapping the G-code coordinates of every letter and word on the board and adding them to a JSON file for the app to read.

The last software step was tweaking the CSS of the web UI so it matched the design of the box.

Future additions for a more atmospheric séance

Right now, a person still listens to questions and types the answer into the web UI. A likely upgrade would add a microphone and an AI model to parse the question and compose a short response, perhaps from ghost character information.

A more ambitious pseudo-séance could add a crystal ball that creates a Pepper's ghost illusion, or link the board to smart home automation so the lights flicker.