Electric Generator Powering LEDs




The Electric Generator is designed to help students understand how electricity is generated by actually allowing them to generate their own electricity. This generator is created using mostly household items. Follow the instructions below for optimal power generation. Have fun!

Materials List
Cardboard Magnet Wire
Metal Rod 2x Magnet
String Red LED (1.6v)
Optional Green (2.2v) and Blue (3.8v) LED    
Suggested Tools:
  • Hot Glue Gun
  • Scissors
  • Sandpaper
  • Multi-Meter
  • Wire Stripper
  • Ruler
  • Electrical Tape

Teacher Notes

Teachers! Did you use this instructable in your classroom?
Add a Teacher Note to share how you incorporated it into your lesson.

Step 1: Building the Housing

Step One
The first thing we need to do is design the housing for the generator. The most important factor in deciding the shape and size of the housing is the size of your magnets. The magnets we are using are Ceramic Block Magnets with a size of 3/8” x 7/8” x 1-7/8”. Because of the magnet size we decided to make our housing 2-1/2” x 1-1/2” x 3”. This leaves enough room for the magnets to spin around inside the housing.
Step Two
Grab your cardboard box or piece of cardboard that you will be using. The thicker or stronger the cardboard the longer it will last. We found the easiest way to build the housing is to cut one length of cardboard and fold it. In our case we cut a piece of cardboard 3” x 8”. We then folded at 1-1/2”, 4”, 5-1/2” to form a rectangle. Just like the picture above. We then used hot glue to hold the ends together. Make sure you use enough hot glue that it holds together quite well. Now that your housing is built you can start to add the wire.

Step 2: Wrapping the Wire

Step One
Take the spool of copper wire and find the end. Use tape to tape down the wire to the middle of the cardboard housing. Make sure to leave enough lead wire off the top to connect your LED later.
Step Two
Now start wrapping the copper wire around the middle of the housing. It is fairly important to have the wire centered around the middle as your magnet will need to be placed in the middle to have enough room to rotate. This is best done with two people, one person spinning the housing and one person holding and putting tension on the spool of wire.
If you don’t have another person with you, don’t worry, you can just do it yourself by holding tension with your one hand and wrapping it around the housing.
If you have a spool already cut to the right length then keep wrapping the wire around the housing until you are out. If you do not have a spool that is cut to the right length then you will need to count. The goal is to get at least 300 wrappings. If you have less than this it would be ok, you’ll just have to spin the magnets faster to create more volts. If you decide you want me volts then wrap more than 300. The number of times around the housing will determine the volts, the gauge of the wire will determine the amps.
How do you calculate how much wire you will need for your generator? First calculate the perimeter of the housing. In our case we know that this is 8 inches because that’s how long of a piece we cut.
So we would calculate 8 inches X 300 and we get 2400 inches, if we want to find out how many feet this is we then divide this by 12. 2400/12 = 200 feet of copper wire.
Once you have finished wrapping the wire tape off the end and leave some wire for the other lead as we did for the other end. Your generator should look like the following picture, except with more wrappings of copper wire.
Step Three
The wire is coated with a layer of non conductive material to keep the electricity from going someplace you don’t want it to. The wire we are using looks very shiny, but we want to get rid of the shiny material by using sandpaper to sand it out and leave only the copper exposed so that we can connect the LED to the generator.
Grab a piece of sand paper or something rough and start scraping the ends of the wires. You only need to sand an inch or two. We folded a small piece of sandpaper and place the wire in-between it and pulled so sand down two sides at once. Keeping sanding until the wire is so no longer shiny. Be careful to not sand too hard as the wire is very thin and can break.
When you have finished sanding the copper wire next you will insert the metal rod.

Step 3: Metal Rod and Magnets

Step One
Take your metal rod and with the sharp end position it in the middle of the copper wire and in the middle of the cardboard. This step is very important and may require you to insert the rod again if it is not in a good spot. The reason this is important is the magnets will be attached to the rod and when it rotates it needs to rotate smoothly without hitting the sides or ends.
Make sure to look at the position of the rod at different angles when pushing through the other side to make sure that it is in the center of the other wall as well.
Once you have pushed it through spin the rod around a bit until it is easier to spin and moves somewhat freely, but not too much that it wiggles.
Step Two
The next step is to attach the magnets to the rod. This part can be a little frustrating sometimes depending on the design of the housing and the insertion of the rod. Place one magnet onto the rod in the center of the housing, then place the other magnet on the other side of the rod so that the two magnets sandwich the rod. On one model we use a bit of cardboard wedge in either side of the magnets to make the magnets sit straight, but this was not necessary.
Spin the rod slowly around checking to make sure that the magnets are centered and do not hit the sides or ends of the housing. When you have gotten the magnets in a good spot then go ahead and secure them to the rod. We used hot glue and dripped it down in-between the two magnets to the metal rod. The other way that might work is to use tape and wrap it around, this worked for a bit when we tried it, but wasn’t the best.
Once you have the magnets secured to the rod then your generator is complete. If you have access to a voltmeter or multi-meter then you can hook it up to it and see how many volts you are generating.

Step 4: Add LED and String

Step One:
Take your red LED and wrap the leads of the generator to the LED’s legs. It does not matter which lead is attached to what LED leg because the generator outputs Alternating Current (AC). If it were Direct Current (DC) then the positive lead would have to be attached to the longer leg of the LED and the negative lead would be attached to the shorter leg.
When you are done it should like something like this:
Go ahead and spin the rod and see if you are able to light up the LED. If it doesn’t light up right away, don’t worry. Try to spin it very quickly and check for a flicker of light. If you are not sure if it works you could hook it up to a drill and spin it with that to see if your connections are good.
Step Two:
Next we will add a string to the generator to help us spin the magnets even faster. Also, if it is done right it can act like a yo-yo and keep spinning backwards and forwards to help keep the light bright. Take your string and tie a knot onto the rod. We have found that close to the cardboard works better then at the end of the rod. Tie the knot and use a bit of hot glue to keep the knot from slipping around the rod. You may also use tape instead.
Wind up of the string either by hand or by spinning the rod while holding tension on the string. Pull the string out quickly and watch the LED light up. You will notice that the string will want to start winding back up the other way, if you let it you can pull again and again and again.
If you would like to see a working version of this generator, watch:

Make It Glow

Participated in the
Make It Glow



    • Indoor Lighting Contest

      Indoor Lighting Contest
    • Make It Fly Challenge

      Make It Fly Challenge
    • Growing Beyond Earth Maker Contest

      Growing Beyond Earth Maker Contest

    45 Discussions


    Tip 5 months ago

    sorry but how much cardbord like inches


    Question 7 months ago

    Would it be possible to upscale everything to power more than one LED?


    6 years ago on Introduction

    Quibbles: That's not shielded wire, just insulated wire of the sort usually called "magnet wire." "Shielded" has a different meaning in electronics. Also, most LEDs have a reverse breakdown voltage not much higher than their forward voltage, so they should be protected from reverse polarity. Two LEDs in back-to-front parallel will do if both are the same color.

    2 replies

    Reply 6 years ago on Introduction

    Hi Wyle_E,
    Thanks for the note of shielded wire, I'll change it to magnet wire.

    We didn't put the back to front LED in the guide, but have tried it out previously and works well. Even with two sets of LEDs it lights up well.

    As far as only having one LED on it, we have tested it out quite a bit and have had no problem with them so far. We noticed the students lose them or break the generator before the LED breaks down.


    Reply 1 year ago

    Vous avez raison c'est du fil de Cuivre vernis , celui je crois que j'utiliserai pour faire des bobinages sur Self, Transfos et pour l'inversion de polarité accidentelle 2 Led en // soit une Diode directement.
    Bon instructable pour les 10 à 12 ans en effet, j'aime vos Tuto. ils sont bien faient , merci à vous.


    2 years ago

    Hi. I was wondering where you purchased the metal rod. I was thinking a hanger could be cut to length, or I could use a skewer.

    2 replies

    Reply 2 years ago

    We actually get our rods from old wire shelves and old CD case holders.Thrift stores are full of them! A screwdriver is a good idea too!


    Reply 2 years ago

    Yes, a piece of coathanger will work. Or a wooden skewer, or even a large nail.


    Reply 2 years ago

    Diode? Maybe. This generator puts out fairly low voltage. A normal diode eats up nearly 3/4 volt. A 4-diode bridge will wipe out 1.5 volts of your output! Perhaps look for "Schottky" diodes, they use less than half the "Vd" of normal silicon diodes.


    Reply 3 years ago on Introduction

    No, the generator is the power supply. you could maybe use diodes to create a diode bridge to output a straight DC signal.


    Reply 2 years ago

    A pencil is a bit lumpy. It must spin smooth. Find a round pencil, or a plastic pen. But too large an axle has lots of friction, and speed might be too low. The thinner, the better.


    2 years ago

    or a screwdriver?


    3 years ago

    Can you replicate this to create a really larger portable generator like these www.generatoraid.com?

    1 reply

    Reply 3 years ago

    I guess with more windings, thicker wire, a more powerful magnet, and faster/ more powerful spin, you might be able to make something useful but there really are much better ways. I don't know much about the AC side of things though, I am sure getting your generator to put out the 60 hertz and everything else would require more technical components.

    EGRoboticsAkash Sinha

    Reply 5 years ago on Introduction

    Hi Akash! Thats great! I'l start with what electricity is. Electricity is when the electrons move from one atom to the next. Electrons an magnetism share a link. You can use magnetism to get the electrons to flow from one atom to another.

    In this case they get pulled and then pushed back because of the magnets north and south poles. This creates AC(Alternating Current) in which the electrons flow back and forth, which we know to be electricity.

    If you are more curious feel free to read about Electromagnetism:


    EG Robotics!


    5 years ago on Introduction

    dude, i knew this a few months ago, i just wanna ask one question, what kind of wire should i use? it's actually calls "magnetic wire" or there's some other name? because i never heard of that name before :P , thanks