Simple, low power, electromagnetic pendulum drive system

This is a little gadget that may be used for simple animations.
Note - I've just posted a new video using a practical electronic drive, that does not need the mechanics switch:    • Electromagnetic Pendulum 2 - The swit...  

The exact mechanical form does not matter as long as it has a free-swinging pendulum of some sort with a curved non-ferrous lower section running through a small solenoid (eg. stripped out relay) coil, and a slim magnet with north & south at the ends, fitted to the centre of that curved section.

Coil activation is by a simple springy contact switch that makes momentarily as the pendulum gets to the centre of the its swing and breaks again around the point the magnet leaves the coil, either way.

As I've built it, it runs well on a single 1.5V cell.