The first magnet (9) is set free to tumble within a tumbling chamber (10). A coil (11) wound around the out surface of the tumbling chamber (10). The two ends of the coil (11) are connected to the terminals of an LED (light emitting diode) (3). There may be some arbitrary, relative motion between the first magnet (9) and the second magnet (2). The magnets depicted with dotted lines represent alternative, relative motions of the second magnet (2) with respect to the first magnet (9). As the first magnet (9) and the second magnet (2) pass close to one another, the mutual interaction of the magnetic fields is sufficient to cause the first magnet (9) to tumble in the tumbling chamber (10). As the first magnet (9) tumbles in the tumbling chamber (10), a varying magnetic filed flux is effected through the coil (11) and a corresponding electric current flows through the coil (11) thus illuminating the LED 3.