Dark side of the Force



Dark side of the force use a single choke instead of a transformer for stepping up the voltage to drive the leds. A CDS photo resistor senses when it is dark (on top of its head).  It is an adaption of the 1-cell boost circuit from Quantsuff's website.

The choke is a vintage toriod from Torotel, marked P 30-55.  It also is marked with a value of 360 Millihenrys.  Thats a lot of inductance in such a small package. Because of the high inductance, the oscillation frequency is very low.  Moving the artbot back and forth will show a flicker.  I ran out of white leds, so I used transparent red ones instead.  In the dark the eyes will start to glow.  The trimmer that forms the mouth can be used to turn down the brightness and the current draw.




PDF of the schematic here.