Shake-A-Can Generator




About: The name Cat’s Science Club comes from my daughter Aly, whom I call Aly Cat. She inspired me to take my love of science, and the fun I have with my students, to as many people as I can. Both my daughters hel...

Shake-A-Can Generator.

Make a simple generator that will help show how electricity is produced.

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.

This idea for our first instructable came from Jonathan Hare at

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Step 1: Materials

35 mm film canister
Thin insulated copper wire*
Magnets that just fit in canister**
Scissors or wire cutters

*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).

Step 2: Put Wire Into Can

Take 35mm film can and remove the lid. Place about (its not rocket science here) 3 inches of the wire into can and close the lid.

Step 3: Wind Wire

Wind on 500 to 1000 turns of thin, insulated copper wire. We recommend the 1000.

Cut from spool of wire.

1000 times wrapped around looks like this.

Step 4: Tape Wire Down

Add a layer of tape to keep the wire from unwinding.

Remember to leave about 3inches or so of wire free at each end.

Carefully take out the 3 inches of wire from inside the canister.

Step 5: Attach LED

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 leg of the LED goes with which wire).

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.

Step 6: Shake

Put magnet into the can and snap the lid back on.

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!


The LED will light!!



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27 Discussions


3 years ago on Introduction

I only have a 23 gauge wire. Is there any possible way I can do this or I really need a 30 gauge wire? I can't scrape half of the wire. :(

1 reply

2 years ago

how about adding capacitor which is holds electricity longer?

1 reply
Cats Science ClubХангайЦ

Answer 4 months ago

Hi. I hope you like the instructable. A medicine bottle should work. Good luck and let us know how it works out.


3 years ago

I made a few with students and some of them worked. But, over time they worked less and less. Is it just the construction or is there a possible reason for that. Pretty awesome when it does light up!

1 reply
Cats Science ClubBeverlyC17

Reply 3 years ago

We found that students that make less wraps need more powerful magnets. We also found that flipping the magnets works to get the light to turn on again. If the magnets aren't straight the light wont turn on. We found that for some of the students, putting in a small piece of pvc pipe inside the film canister, helps keep the magnets from flipping on their side (if the magnets are to small for the canister).

We have students who have theirs from three years ago and have no problems. The kids really enjoy these and next years class is already looking forward to making theirs. :-)

Please let us know what helps!


4 years ago on Introduction

If you want the LED to stay on for longer periods of time (perhaps mins) than

I would like to suggest this YouTube link , ENJOY

2 replies

Thanks so much for the video and comment. We have turned this into a flashlight using what we learned on and some guess work. Our problem is just what was mentioned in the video. Our capacitor would discharge to quickly and we had to shake the can often to recharge the capacitor. We were and are very happy we had it working at all but now we are getting excited about it staying on even longer. Thanks!

You're very welcome!

That video is another example of the endless fun of electronics and related hobbies.

Once again Thanks to it's Author Afrotechmods


4 years ago on Introduction

its asuper and simple way to lit the LED with out any other device .simple to understand and prepare.


4 years ago on Introduction

If you use 2 LEDs, connected in parallel (with the long wire on one connected to the short wire on the other, and then the short wire on one connected to the long wire on the other), instead of just one LED, you'll get twice the light.

It's a little simpler than wiring a bridge rectifier, but it's the same idea: One or the other LED will light, depending on which way the current is flowing.

1 reply

It looks like you're using ceramic magnets. If you put a neodymium ball magnet inside the canister, You can wave another magnet in front of this and the led will light up without touching anything. If you attach that other magnet to a bike wheel, you can make a bike light that blinks without touching anything or shaking. If you look at my bicycle wheel windmill you can combine all these things. There is a product on the market you can find by googling freelights bike generator that does this same thing.

1 reply

4 years ago on Introduction

Cool, maybe with a bridge rectifier with low power diodes (like schottky diodes) and a small capacitor you could power the LED more efficiently.