When spun rapidly
between the fingers, a bipolar stepper motor will generate around 10VAC.
If this is stepped up with a small 240V to 6-0-6V transformer in
reverse (with series connected secondaries), a small bipolar stepper
motor is capable of powering a standard 5cm by 6cm luminescent sheet at
full brightness. These are designed to be powered from 20V to 200VAC
(typically 115VAC), producing 1.5 candelas of light – which will dimly
light the average room, or adequately light a camp table. They are
manufactured by Seikosha (RS Components Cat. 267-8726).
The transformer should be a small one (around 100mA or so),
otherwise efficiency is compromised. The wires of the motor’s two phases
are usually paired white & yellow and red & blue. Just one of
these phases is employed in the circuit. If a small bipolar stepper
motor from a discarded 3.5-inch disk drive is used, the Luminescent
Generator may be built into a very small enclosure. To sustain rapid,
smooth spinning of the motor, a geared handle may be added.
Author: Thomas Scarborough – Copyright: Silicon Chip