Physical hardware build in progress — coils wound, PCB designed, ferrofluid sourced.  ·  michaelwmartinjr.com

FerroBot

4×4 electromagnetic coil array shaping ferrofluid into dynamic patterns. Physics simulation: Rosensweig instability, Langevin magnetization, viscous damping, surface tension.

Fluid Surface — Height Map
Coil Array — PWM Intensity
Pattern: Traveling Sine Wave 60 fps
Wave Patterns

How it works

Each coil generates a magnetic field that pulls ferrofluid upward against gravity. Where fields from adjacent coils overlap, the fluid rises higher — this is the Rosensweig instability. The simulation models magnetic force, gravitational restoring force, viscous damping, and surface tension as a coupled PDE system, solved with Verlet integration at 60 FPS.

Grid
4 × 4 coils
Fluid resolution
8 × 8 grid points
Coil spacing
25 mm
Max spike height
15 mm (12V)
Physics step
16 ms (60 Hz)
Field model
Langevin &tanh; curve

Research direction

Ferrofluid at the Rosensweig instability threshold exhibits complex, history-dependent dynamics — a hallmark of reservoir computing substrates. The project explores whether the fluid can serve as a physical echo-state network, with coil inputs driving transient states that linear readouts can decode.