Blinking an LED using a generator as the source of electricity
Technical Explanation:  The open circuit voltage produced by your generator is too low to drive any current through the LED.

Straightforward Explanation:  Your problem is probably that there aren't enough volts produced by the generator, even when the LED isn't connected.  You can measure this with a simple multimeter when spinning the generator.  Set the multimeter to 20V AC or DC and see what voltage you measure.  To get the LED working you should see at least 1.4 volts for a RED LED, 2.5 volts for blue, or 3 volts for a white LED.

Others have suggested a resistor is necessary to prevent damage to the LED.  Normally, this would be true, but in this case as the LED starts to light up, it will slow down the wind turbine, protecting itself in all but the strongest winds.  Additionally, most generators have the equivalent of a resistor inside them.

One suggestion is to use a microcontroller/capacitor.  The problem with this solution is you will not be able to get a high enough voltage to power up the microcontroller.

My solution:


Use a Red rather than white/blue LED.
Use no resistor (or if you do, choose
something below 300 ohms)
Spin the generator faster - use gears
to up the speed and lower the torque
if necessary
Get a different type of generator
designed for slow speed use.
If you have multiple LED's, connect
them all in parallel (ie. every LED
connects direct to the generator)
Make sure you're spinning the
generator the right way - test
spinning it backwards, or connect the
LED the other way round.


Note:  Human eyes are very sensitive - if the output voltage of the generator is high enough, even a tiny current flow will cause the LED to visibly light up in the dark.

Additionally, there are many types of generator, AC/DC, brushed and brushless etc.  In this situation, it doesn't really matter which you choose.