Pedal Powered EL Wire Bike


Instructables user [samsmith17] wanted to cover his bike with EL wire for this year’s Burning Man, but he didn’t want to mess with the hassle of using batteries as a power source. Instead, he decided that his EL wire bike would be powered solely by the rider. In the interest of keeping things green, the entire build is made up of re-purposed parts, aside from the EL wire itself.

If you are not familiar, EL wire only lights up when AC current is supplied, so he decided to use a stepper motor to generate the current required. The stepper motor was mounted against his bike’s wheel, and wired backwards through the AC transformer portion of an old cell phone charger in order to step up to the required voltage. A rheostat was also added to the circuit in order to help prevent an over voltage condition, which could potentially damage or destroy the EL wire.

The end result is pretty cool to watch, and costs very little to boot. It would be nice to see someone expand on his project, adding additional wire colors and perhaps a few capacitors to keep the wire from going dark immediately after the wheels stop turning.

Continue reading to see a quick video of the completed project.


31 thoughts on “Pedal Powered EL Wire Bike

  1. What kind of capacitor would keep AC flowing to the EL wire? Putting energy storage in this project would necessitate a rectifier and an inverter stage and destroy the hack elegance of it. How about a mechanical flywheel instead?

  2. A capacitor will not help unless you also add a great deal of additional circuitry to turn the stored DC on the cap to AC. At that point, why use a stepper? A DC motor/generator would be the obvious choice.

  3. @Kuy & rasz,

    Sorry about the cap comment, my mistake. That’s what I get for writing something up after midnight. Any thoughts other than a flywheel?

    The EL wire could be a nice safety feature for nighttime biking, provided there was a way to keep it lit for a bit once you’ve stopped coasting.

  4. I know he didnt want to mess with batteries, but battery use while not pedaling could work out. Not sure how much longer that would save on battery than if he just used a battery all together.

  5. I’m no electronics expert, so this might not work. But I doubt the EL wire requires a perfect sine wave to light… so maybe a square wave approximation of AC would work?

    A rectifier after the stepper would convert the AC to pulses of the same polarity, and a capacitor would smooth that so it’s closer to DC, as well as provide storage. Then the almost-DC could be pulsed (maybe using a 555 and a transistor?) through a transformer to step it up. It would have a horribly noisy signal but might be good enough to light the wire with very few added components.

  6. @ProfP

    It looks like this project had a goal of using recycled parts. It stands to reason that he may not have had a spare dynamo in his parts box, thus a stepper motor isn’t a bad choice. Plus the extra whine makes it more striking in my eyes/ears.

  7. @Alex
    Yes, that should work. But if I remember correctely, those cheap EL wire inverters you get with the wires require quite a bit of current. I don’t think that the 555 version will need much less so you’ll need some really big caps.

  8. RE: Care and feeding of both Inverters and EL wire.

    The numbers given by rasz seem in line with what I’ve seen many EL materials both wire and flat sheet replicating. With the usual “not always” is an understatement, cases. Flat planar EL sheet Vs round wire demands divergent Inverter output factors. Rather not unexpectedly- round wire has less C to nearby metal but the frequency “tilt” of current to frequency is non-linear in proportion to wire routing facts. Which can make some layouts like sign letters Vs Straight Long Planes act way differently at times.

    Remember the Non-linear bit and you may avoid some brain stress trying to figure out why stuff malfunctions weirdly different that you’d expect..

    EL wire has regions of Voltage/Waveform+Frequency and CURRENT all intersecting to affect lumens/color/lifetime. Choose Carefully. If you have the ability to apply a design ruleset for those parameters, you can tweak them for your project’s needs. Same applies to what you “feed” Inverters. A raggedy spiky fugly “Wild” Waveform can be digested differently by Inverts of one “first stage” design or another.

    Seemingly identical designs can melt swiftly on the garbage laden volts or last- forever.

    In theory, everything can be solved with math properly applied. In practice it’s often not that easy due to variables caused BY using random cruft from our junk bins. Or variables like distributed L/C of both the EL wire and Hookup wire between Power Source/Inverter/EL wire itself. At DC, such factors are negligible. at Khz or Mhz resonances- they become demonic. Enough of the exasperating ways Math defies reality or the reverse for a moment..

    Sometimes the just whack it together and watch it work modes are smarter than exhaustive overthinking. Design for an Art Hack Vs something to last forever can be worlds apart.

    Point Scored by this Hack for the “it works” factor:>

  9. You’d be better off with a DC generator charging capacitors and then chopping up the capacitors with a switch type power supply that converts to AC. Then you get the best of both worlds, namely persistence, and the ability to regulate voltage.

  10. This would add significant complexity, but it would be interesting if you could employ some slip ring type connectors to the wheels and put some EL wire on the rims, as well. You might be able to use the frame as one connector (through the hub bearings) and some “whiskers” on the rim that were kind of like the brake pads, but were always engaged. If the circumference of the rim had a slip ring connector, I think it would work. It would be prone to fouling, but if you had a little set of bristles/brushes that were cleaning the surface continually, that should keep it clean…

  11. different EL wires bend differently
    there should be info how much you can bend particular EL wire in the documentation that comes with it
    mine said to never go below 2cm diameter when bending (use something with 2cm diameter to bend the wire around it)

  12. RE: comment I missed about “Bloody Dynamo: there’s several sorts of wordplay lurking there but keeping on a linguistic track- Dialect between contries etc often does confuse techs from “other places” similar to my experience of folks from BC referring to a power pedestal as “the hydro”

    @David: Brushes are often just that in some applications. Slot cars used pieces of silver or copper braid strip that slid against the track rails on the sides of that “slot” in the track. The same trick “could” be replicated on a brake disc mounted on insulators. in fact- it would be very instructional to Hack at. Some scavenged carbon motor brushes aimed at an area of a brake disc %not% swept by brake pads might do to carry power. Me personally, I’d run the DC to the Invert thru the brushes. And then filter the DC for spikes/crap.

    As subjecting an Inverter to such brutal abuse is needless cruelty to innocent components.

    Filtering the DC is way easier than protecting the Inverter’s output from Rain/scrud/mung of unknowing origins on those brush/slip rings etc.

  13. not reading all the comments, but what about 2 diodes, 2 capacitors, each set opposite of the other.. and some other crap after that i guess to turn each cap’s stored energy back into pulsed DC which is then…and routed to the..
    /your mom goes to college, maybe she can help figure this out.

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