This is a relatively simple instructable that uses advanced EL wire techniques. If you've never worked with EL wire, check out some of the other great EL wire instructables first. You'll need to know how to solder and connect it before doing this project.

Since the whole point of this instructable is using repurposed parts, it won't be exactly step by step. Instead I'll guide you through finding and choosing parts, and testing them. Then you can apply it to your project as necessary.

EL wire is a copper wire covered with a phosphorescent coating. 2 extremely thin copper wires are wrapped loosely around this coated copper wire, and the whole thing is covered in plastic. When AC (and only AC) current at about 90-130 volts is passed through the outside and inside wires, it excites the phosphor, and the wire glows like a neon tube. It's very, very cool stuff.

Generally, you need a driver to convert low voltage DC battery power in high voltage AC power. These inverters are available online, but there are a few problems:

1. They break. Quite often.
2. They aren't expensive, but they aren't cheap either.
3. You can pretty much only get them online.
4. They require batteries.

I wanted to put EL wire all over my bike for Burning Man this year, but I wanted to light it with pedal power. No worrying about charging or hauling batteries, just pure muscle power. I had an old stepper motor lying around and I remembered that they ONLY produce AC current. Usually you have to rectify it to DC to use it. But I needed AC! Could it be possible to hook an old stepper motor up to light EL wire with no driver all? The answer, it turned out, is yes, and not only that, it fades on and off with speed, and can even change color (slightly) as the frequency of the AC signal changes. SCORE!

Here's a video of the final project in action. This is before I got the wheels lighting up too. In the first few seconds of riding, you can see the color shift from Green to Blue, because of the change in frequency as I speed up. Also, I should warn you that this is on my swing bike, which has two pivots, so the video may be confusing if you've never seen a swing bike in the day-time:

http://www.youtube.com/watch?v=0n2m4cs3lx0

Now, on to the disclaimers:
First, this instructable deals with electricity. Be sure you know what you are doing. I gave myself a few nasty, though not life-threatening, shocks along the way.

Second, sending unregulated power through EL wire could short it or shorten its useful lifetime. It's importand to size the output of your generator at speed to your transformer so you don't damage the EL wire.

Step 1: Parts List

Here's what you will need to make this work:

A bike
EL Wire
A Stepper Motor
An old cell phone charger
A Rheostat (optional but highly recommended)

Tools:
Multimeter
Alligator clips
Electric Drill

In each of the following steps, I'll show you what these parts do, why, and where to find them cheap.

Step 2: The Stepper Motor

Stepper Motors are little motors that can "step" by very small increments. They are used when a motor must turn very precisely. You can find them in old dot-matrix printers and copiers and other computer hardware. If found mine for $5 and FreeGeek, a non-profit used electronics store in Portland. Many cities have placed like these, if you can't find one, you can order steppers online for a few bucks, but its definitely more fun to try and scrounge one.

Size: The one I ended up using was pretty big, but I also had a smaller, more common one that lit up a string of EL wire about 5 feet long. It didn't seem to be powerful enough to light the 30+ feet on bike though, so I went with the bigger one.

Wires: Stepper motors have a bunch of wires coming out of them Usually 5, 6 or 8 of them. Check out this page for the wiring http://www.reuk.co.uk/Stepper-Motor-Basics.htm

Once you figure out which wires are Live and which wire is common, you can just pick any one of the live wires, and the common wire, and attach them to your multimeter. Use an electric drill to spin the motor, and see what kind of voltages you get. I got between 4-10 VAC on mine. If you're on really good terms with your electronics store, they might let you do this in the store, so you know exactly what kind of output you'll be getting.

Now we have to ramp that low voltage AC to high voltage AC. This is where the cell phone charger comes in.

Step 3: The Transformer

Your typical cell phone charger uses a transformer to take 115VAC house current and step it down to about 5VAC, which is then rectified into the 5VDC that charges your phone. If you're unfamiliar with transformers, check out the wikipedia page, its really cool.

Basically, the ratio between the number of windings on one side of a transformer and the number of windings on the other determines the output voltage. Since we already know that a cell phone charger has the correct ratio to convert between 115VAC and 5VAC, we don't have to do any of that math. We'll just wire it in backwards and have it step up the AC current from the stepper to a voltage the EL wire can use.

Inside the charger you'll find the wires from the standard wall plug going into a big heavy blocky thing like in the picture. This is the transformer. At the other end are 2 more wires, which will be soldered to a little circuit board. The circuit board rectifies the current to DC, so we don't need it. Snip off the two wires that are coming out of the transformer.

Then all you need to do is hook the live and common wires coming from your stepper motor into the two wires that were connected to the rectifier. The low VAC will become high VAC. Test with your multimeter and the drill again, and see what kind of voltage you are making.

Now you need to size your transformer to your stepper, to make sure you are making the right amount of power.

Step 4: Stepper to Transformer

Every stepper/transformer combo will be different. If your pair isn't putting out over 90VAC even when your drill is screaming at top speed, you may want to find a charger with a higher ratio. Look for one that goes to 3V instead of 5V. This will step your voltage up more.

Once you have one thats powerful enough you have to worry about it being too powerful. Your ideal goal is a pair that produces no more than 130VAC when you are going top speed on your bike. Any more than that and you'll almost certainly blow out your EL wire. This is why the Rheostat is so handy. A Rheostat is just a dimmer. It increases resistance, and thus decrease the voltage going to the EL wire. If you don't have a rheostat, there will be a certain speed at which you will produce too much AC and kill your el wire- not a fun thing to have to worry about when you want to go fast!

If you put the Rheostat between your EL wire and your transformer, you can tweak it so that even at your tippy-top speed, you still can't blow out your wire. Just hook up the rheostat output to your multimeter, and a fix your multimeter to your handlebars securely (duct tape works fine). Do sprints and keep tweaking the rheostat until you can't get the power above 130VAC. (Note: I use 130 VAC as a guideline. It may be too high still. And the brighter your EL wire glows the shorter it will last. Use your best judgement, it will look really cool even if it's a bit dimmer)

It might be a good idea to blow out about 12" of EL wire so you know what the warning signs are. As you increase the power, it fades on, then gets brighter, and brighter, and starts to change color (if your using green-blue, it will change from green to blue) then it starts flickering, and then it dies.

Step 5: Getting It on Your Bike

Now that you've tested your set up, it's time to affix your generator to your bike. That can be done a bajillion ways. I superglued roller from an old office chair to the spindle to create a wheel that would just roll along the tire. I had dreams of making it spring loaded, but I never did and it works fine.

Check out these fine instructables:
https://www.instructables.com/id/Bike-Generator/step4/Hook-everything-up/
https://www.instructables.com/id/Bike-light-generator/step3/Fitting-Stepper-Motor-to-Bike/

And get creative! Every bike is different, so I can't help that much on this part.

Step 6: Setting the Upper Limit

If you put the Rheostat between your EL wire and your transformer, you can tweak it so that even at your tippy-top speed, you still can't blow out your wire. Now that your generator is hooked up to the bike, just hook up the rheostat output to your multimeter, and affix your multimeter to your handlebars securely (duct tape works fine). Do sprints and keep tweaking the rheostat until you can't get the power above 130VAC. (Note: I use 130 VAC as a guideline. It may be too high still. And the brighter your EL wire glows the shorter it will last. Use your best judgement, it will look really cool even if it's a bit dimmer)

It might be a good idea to blow out about 12" of EL wire so you know what the warning signs are. As you increase the power, it fades on, then gets brighter, and brighter, and starts to change color (if your using green-blue, it will change from green to blue) then it starts flickering, and then it dies.

Step 7: Putting It All Together

Now all you have to do is put this all together into a kick ass bike project. I know I've left a lot to figure out yourself. But that's the point isn't it? It was really a blast realizing that this should work, then getting the all parts and doing all the experiments, and finding out it does! I just wanted to make this instructable because when I was researching this project I couldn't find any information about using steppers as EL wire drivers. I hope I've given you some food for thought for your next crazy project.

P.S. I also want to win that laser cutter... so if you dug this instructable, vote for me, or something.

Step 8: So, About That Laser Cutter...

When I wrote this instructable, I didn't think it would have much of an impact, so I didn't really put my heart into explaining what I would do with a laser cutter if I won the Epilog Challenge, per the contest instructions. But it the past few days, its been featured on MAKE and on the front page of Instructables, and gotten over 8000 views, so maybe I've got a shot!

So first, I'd like to thank everyone who's commented! You've all been very nice and extremely helpful!

What I'd do with a laser cutter:

I'm an artist/tinkerer/screenprinter/mad scientist based in Portland, OR. I have wanted a laser cutter for years. Anyone who doesn't want to burn and cut stuff with a computer controlled laser should not be trusted. There are a million things I could do with one, but here are the first few that come to mind:

-I make organic t-shirts for a living (lonelydinosaur.com ) and I've been experimenting with making our shirts more sustainable, particularly by using less ink or alternative imprinting methods. With a laser cutter, I could create laser cut stencils of my prints, place them over a shirt in a box, and leave the shirt out in the sun for a few days, allowing the UV to create a solar powered, ink-free print. Just a thought, but something I'd be interested in experimenting with.

- I could share use of the machine with the fledgling Hackerspace here in Portland, called the BrainSilo, and the other independent artists and makers I work with.

-Using EL wire and laser cut clear and colored plastic, I could create an awesome neon-type sign for our t-shirt business.

-My girlfriend is an artist, who does mostly pencil drawings, so we could scan and transfer her drawings to wood or acrylic panels, opening up a new mixed media outlet for her work.

-I want to make a new gear for my Electric Scooter (the Ego with the flat tire in the background of the 4th picture) The gear has 6 holes and bolts to a disc brake hub, and costs way too much from EGO. By cutting several panels of acrylic and layering them, I could replace the gear as it wears out, and even change the size of it to get different torque ratios, ie make the scooter go faster without changing the motor.

I've used an Epilog before, and it was awesome, but it was cruelly taken away from me when the Portland Techshop closed down. Please consider me for the contest, if I win, you can bet there will be an Instructable on every single one of these projects!