Perpetualpendulum Diagram
Perpetualpendulum

This project uses reed switches and electromagnets under Arduino-control to keep a small magnet pendulum swinging indefinitely. The Arduino uses the reed switches to keep track of pendulum movement and powers the electromagnets whenever a little ‘push’ is needed to keep it in motion. Check out the thorough documentation for more good info (and neat diagrams!) – Arduino Perpetual Pendulum

Related:
Solar Pendulum Crop
Solar Pendulum