Most of us check a wave buoy website and read numbers. The maker, a maritime pilot in Belgium, wanted the sea itself on the desk: a small 3D printed west cardinal buoy hung from eight lines, each one winding onto a spool on a stepper. Feeding the lines in and out together lifts, drops and tilts the model, and an ESP32-S3 drives it all from live readings off public buoys, including NOAA, CDIP, the Irish Marine Institute and Belgian and Dutch North Sea stations.
The frame is a neat rectangle of white printed parts and round wooden dowels, with motors wearing green spools at the four top and four bottom corners. Electronics look tidy too: eight TMC2209 drivers on UART through TMCStepper, running silent StealthChop with no Vref pots to fiddle with. A 1.9 inch LCD and a rotary knob pick the buoy, WiFiManager handles setup by QR code, and power arrives over USB-C through a HUSB238.
The motion side is what impresses me. One hardware timer fires the step pulses for all eight motors, and a task running at 100 Hz recomputes position, tilt and all eight line lengths every 10 ms. Fresh wave numbers arrive every half hour, and for CDIP buoys the last 30 minutes of recorded motion gets replayed in real time, interpolated up to that loop. At startup all eight lines wind in at low current until each motor slips, and that is how it homes without endstops.
Two things remain open. There is no tension measuring at all; the maker called real sensing a nice upgrade but has not committed to it. The STL and build instructions are also still pending.