with a 3k resistor, a 4200uF capacitor, 2 calculator solar panels and an old CD player motor. Under a table lamp, the capacitor charges for about 25 seconds, then the FLED starts flashing, after another 15 seconds the motor spins. What I don't understand, is if the FLED is flashing then why doesn't the motor spin immediately afterwards?
That 50 mA of current flows into the base of the NPN and is amplified by about 10 to drive the motor. As long as the motor draws no more than 500 mA this circuit will work fine. If the motor current is much less, then increase the resistor value correspondingly. If the motor draws more current then uses a smaller resistor. Be sure to use a PN2222 or equal for the NPN for current greater than 200 mA.
I plugged my multimeter in series with the motor, and when it spun, the meter showed 0 mA. My guess is my meter isn't quick enough to show how much current the motor is drawing.