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The Science

This is the simple explanation. A generator works because the magnets are exciting the electrons in the coil. The magnet moving back and forth creates alternating current (AC).  That is the electrons are moving back and forth through the coils and the LED (light emitting diode).  The excited electrons passing through the LED lights the LED.

For more comprehensive information go to


*Jonathan Hare at is where we learned about the shake-a-can.

*We used 30 guage magnet wire

*Neodymium magnets work best but we were able to get the light to turn on with ceramic magnets (much cheaper).


  • 35 mm film canister
  • Thin insulated copper wire*
  • Magnets that just fit in canister*
  • Red LED
  • Tape


  1. Take 35mm film can and remove the lid.
  2. Place about (its not rocket science here) 3 inches of the wire into can and close the lid.
  3. Wind on 500 to 1000 turns of thin, insulated copper wire. We recommend the 1000.
  4. Cut wire from spool.
  5. Add a layer of tape to keep the wire from unwinding. Remember to leave about 3inches or so of wire free at each end.
  6. Carefully take out the 3 inches of wire from inside the canister.
  7. Scrape off 1/2 inch of insulation from the ends of the wire (using sandpaper) and connect to the LED (it does not matter which way round).
  8. Solder the connections if possible or wrap the exposed wire to the legs of the LED. Use some tape to secure the wire and LED to the bottom, top, or side of the can.
  9. Put magnet into the can and snap the lid back on.
  10. Hold the can between thumb and forefinger at the two ends of the can (with thumb or forefinger on the lid to stop it coming off !) and shake. The LED will light!!

Our steps also available at

More info and where we got the idea is at -

Shake-a-can Generator*