Making Electricity in Your Hand




Posted in TechnologyScience

Introduction: Making Electricity in Your Hand

About: Im an ex computer guy who turned locksmith then Resource Conservation Coordinator for a school district and I still love to tinker with everything. During the last 3 and a half years, I sold the school boar...

In my research to make an alternator for my Savonius VAWT wind power project, I learned there is a great deal of mystery around making them. I even read one article that referred to home brew alternators as a dark art shrowded in mystery. I dont think it is all that poetic but I did agree that for a novice with no real electrical background that it seemed a mystery. Kind of like a cookie recipe, you know there are things like flour, eggs and sugar, but how does it go together? What job does each ingredient do? How is it mixed or assembled?

From my experimenting, which is not over by the way, I found that this simple excercise was the most revealing.

You will need a huge magnet like used in a wind power project. The rest is available through normal hardware store or RS. I'm sure a good sized speaker magnet would probably work if you have a sacrifice to make.

1 small spool magnet wire (about 30 feet of 24AWG)
1 bulb from or for a keychain flashlight (two refills for $1 around here)
1 Neodymium magnet 1inch x 2inch and 1half inch thick (about $10 plus shipping and any tax)

Step 1: Get Wire Off the Spool and Re-wind It

This seems like a goofy idea, the wire is already so neatly wound on the spool. The problem with the spool is the big hole in the middle. You need to re-wind the wire with a nice small hole and relatively flat.

The idea is to expose as much wire to the highest concentration of magnetic field as possible without shorting the wire in the coil. This is why we use magnet wire. It isnt magic wire that makes electricity, it is just that magnet wire has a much thinner sheath and its usually made of enamel.

The extra thin sheath allows you to cram more wire in the same space as you would regular wire.

The attached mov file is my drill coil winding jig in action.

Step 2: Why Wind It Flat?

Well, optimally you would wind it to be the same shape as the magnetic field that will go over or past it. My magnet is rectangular and relatively thin. So for this instructable, make the coil about 1quarter of an inch thick or half the thickness of the magnet.

Magnetic fields drop off with a very high curve. They are strongest when in direct contact with a surface. This is why we want to put our wire into a shape similar to the magnet and be able to get it as close as possible for exposing the coil of wire to the magnetic field.

In commercial applications, there would be a metal in the hole of our wire coil. We are not going that far. It is there to draw the magnetic field more completely through the coil. More efficiant in some ways. Not here.

Step 3: Now What? Its Wound Flat... Sort Of...

Probably good enough for this simple experiment.

Tape it up with two leads hanging out.

I know the image isnt the sharpest, but we are looking at one lead from the coil. I stripped the end with some sandpaper and then coiled it around a small screwdriver.

Do this or something similar to strip both ends and make a couple of tight loops. This is not critical, it just gives us a point to attch the light bulb without soldering.

Step 4: Remove Bulb From Flashlight or Packet If You Purchased One...

You want to put one leg from the bulb into each prepared coil lead. Then pinch the coil snug on the leg to hold it. This is just an experiment to illustrate the process of making electricity. If you like, you can make a more significant attachement. I found this worked fine while I would wrap different shapes of coils and check the voltage I could generate.

Step 5: Hold the Coil and Strike the Magnet Here Come the Electrons!

If you are familiar with lighting a match, this next motion is similar.

While holding the coil in one hand, hold the magnet in your dominant hand and slowly motion the magnet past the coil. This is to visualize what you are about to do quickly and to make sure your thumbs are not in the way or the two wire leads. If anything is in the way and might get caught, adjust accordingly.

Now as you will pass the magnet swiftly over the coil, you want to get as close as you can without hitting it. The flat side of the magnet face to face with the flat side of the coil. This is a side to side, not up down motion. The speed the magnet passes has an effect on the voltage created. You will feel a vibration in the coil when everything works right. This is NOT electricity flowing through your hand. It is a ripple effect or vibration from the coil making sudden drag on the magnet and the leads hanging out.

If you move the magnet past fast enough and your contacts are good and you have enough length of wire in your coil, your light should blink on with each pass.

Step 6: An Alternator...

An alternator creates Alternating Current or AC. Many alternators use all coils and no permanent magnets. You will need to research this if you really must know how they work. The power we just made in our hand is a permanent magnet generator or PM generator. I wont call it an alternator because we are not flipping the magnet at each pass to alternate the north and south sides.

When you build a wind power generating machine, you are putting together a team of these coils and wireing them for optimal performance. Then you are mechanizing a motion of the permanent magnets to blast past the coils as the machine turns in the wind. Thats the summary.

Check out my savonius rotor project PDF for more details on the alternator.

The attached mov file is my hands striking past the coil and the bulb lighting up.



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    ok so do you know the song bangarang and the kid that has the electricity coming from his hand I want to have something like that.

    Couldnt you better use a Diode bridge so it will burn when you go eitherways...?

    for future reference just use a lighter and burn off a half an inch or so

    it makes sure the whole contact is clear and its much faster, decent instructable though

    1 reply

    I actually tried burning but found I needed to use sandpaper to clean the carbonized enamel from the wire anyway.  This stuff is so small it really is very little effort to clean with sandpaper.

    add a capacitor instead of the bulb to store charge and dont forget the diode to retain charge in this way u can store energy

    If you want to purchase some good magnets, then go here. Where can I get info on how alternators work in a way a novice would understand? I can't find much on "how to build an alternator" (or a dynamo, for that matter). Only "this is what alternators do: blah, blah, etc. No information describing how and why they create AC in language an amateur could understand.

    2 replies

    THe best way I've seen AC explained was an upside-down 10-speed with the chain marked in one spot. As the mags move across the coil the field pushes and pulls the electrons back and forth in the wire. If you jog the pedals the same way keeping the marked part of the chain in a range of a few inches the pulses will spin the wheel faster & faster.

    Hi, I will just take a second to describe why alternators make AC. Imagine you have two of these coils, wound exactly the same, sitting in the same position. Now imagine you flip one of them over so that the coil is wound in the opposite direction of the other. When the magnetic field traveling past them is the same, the opposite direction of flow will be generated in them because of their orientation, mirrored positions. The reason we like to make AC is because the current generated is stronger the more variance in magnetic flux, so in turn the most effective way to accomplish this mechanically is by the simple orientation of the coils or the magnets. Often, with a permanent magnet alternator, we flip flop the magnets and make all the coils the same. Imagine how inefficient it would be to pedal a bicycle if both pedals were in the same orientation, it would be like hopping and not like pedaling. AC is like offsetting the pedals by 180 degrees to create the most optimal use of the mechanical change. Potentially the same energy is there, but with the 180 offset we are more efficient at collecting it. Now if you are thinking, the magnetic flux is still coming from the same source at the same distance so why would it follow the direction of the wire, you would have a good question. The electrons traveling around a copper atom are always going the same way by nature. This means if we set a few free by inducting a magnetic field, they will pick up their direction by the spin of the electrons on the atom. Since this is naturally occurring we can pretty much count on the result to be predictable. So don't over think it. Let it sink in that this is how it happens and worry about the rest in physics class.

    Thanks , it is really wonderful . I will try to make one like that -

    magnet wire is just copper wire right? cant you just get that from radio shack?

    4 replies

    Magnet wire is just copper wire, but the insulation is a thin coating of enamel instead of thick pvc like normal wire. Yes it is available at RS, but when you need this much, you will probably want to order it from somewhere.

    ok cool thats what i thought, and i was wondering what kind of magnets i should use, i was looking at the N42 1/4" thick with 27lbs of pull force, but i saw yours was 1/2" thick, would mine be sufficent for making my prototype?

    The 1/4" thick ones will probably be ok. I have not tried them. - I think I answered this in an Orangeboard. : )

    hahahahaha oops, soory i didnt see that message in my inbox doh!

    Correct me if I'm wrong, but doesn't this produce an AC current? If so, you'd need an AC to DC converter to power your LED.

    5 replies

    What is an AC to DC converter? It is at the most basic level just a diode which half wave rectifies the current from AC to DC. More complex devices will contain about 4 diodes and some smoothing capacitors.

    True. However I don't use an LED, see the flashlight in the photo... I use its 1.5V bulb.

    cant you just put a few rectifiers on it and than that will put it to in the tic tac light???

    You can, but this is pulsing DC, always the same side of the magnet passing the coil. This is really a great experiment from Fariday to illustrate how electricity is made in a permanent magnet generator or alternator. Current is only made as the field from the magnet is in motion passing the coil. This is a good starter experiment if you want to learn how electricity is generated and how it flows. Use an LED and discover that it will work with the magnet held one way but not the other. LEDs are a form of rectifier in that they only light when power flows the right direction.

    By using only one side of the magnet, you're only limitating the flux to half the potential between 0 and Fmax, if you're using both sides, you get -Fmax to Fmax, but because the currant generation is based on the derivative of the flux, you'd see surrant going in both dircetion in both case... To us this current shape, maybe put 2 leds in opposing polarity... It would go darker when the magnet is reaching the end of its course though...