In this project I wanted to add EL Wire to a motorcycle helmet. Even though I don't have a motorcycle or ATV to use it with, it still makes a good costume piece. For those that do ride vehicles that require a helmet, the addition of the EL Wire will make you more visible at night, hopefully increasing safety. Plus it looks super cool, like a character from TRON.
EL (electroluminescent) wire is an interesting component. It features a copper wire that is coated in phosphor. When electricity flows through the wire, the phosphor will react and create light (SCIENCE!). Because the EL wire is flexible, it is a good way to add strands of light to an installation or fabric. Projects where LEDs may not look as clean in lines could benefit from EL wire or tape.
EL Wire glows blue naturally, but the wire can be wrapped in different casings to change the color to pink, red, yellow, green, etc. Pick whatever color you prefer and is available to purchase. I chose TI LaunchPad red for this build, available from Sparkfun and other online stores.
To drive EL wire it takes 120V, so to control the EL wire from a low power microcontroller we will need to use an EL inverter that can take 3.3V input. Luckily Sparkfun has one of those available.
Another thing to note is your Launchpad does not have enough current on the pins (less than 50mA) so if you try to drive the inverter directly from the pins, the glowing will be very weak. This means we need to use a transistor or MOSFET to power the inverter from the 3.3V rail available on the LaunchPad.
With an inverter it is a basic on and off digital operation, so the only thing we can control from our LaunchPad is the speed that it can blink. Hook your transistor/MOSFET circuit to one of the digital pins on the LaunchPads and program the delays between the EL wire turning on and off to achieve different visual effects.
* Motorcycle helmet - Amazon has them for under $60 in many styles
* EL Wire - https://www.sparkfun.com/products/10191
* EL 3.3V inverter - https://www.sparkfun.com/products/10201
* MOSFET - CSD18532KCS
* MSP430G2 LaunchPad - http://www.ti.com/tool/msp-exp430g2
* Battery BoosterPack (or other power source like AA battery pack that can fit inside the helmet)
The first step is to make your design on your helmet. Eventually you will want to glue your wire down, but in the beginning you can use scotch tape and start taping your design to the helmet. Try to avoid taping things on any moving parts, this will make it less complicated and more solid. For example, on my helmet, the face mask lifts up. I started by making the mistake of putting the wires in they way of the moving parts, if you avoid this, you won't have any trouble when finalizing your design.
I started with the tip of my EL wire on the corner edge of the face mask and started wrapping the wire in designs around my helmet. If you have any excess wire you can always try to stuff that inside the helmet at the end of your pattern. It is also possible you can run out of wire before your design is done, so make sure you buy a long enough strip.
Remove the inside of your helmet liner to make things easier. On my helmet there was some padding and a foam insert. To make space for my electronics to fit inside the helmet I cut a good sized hole into the foam insert. Now my LaunchPad and inverter can fit inside and I can still wear the helmet pretty comfortably.
On my helmet I could thread the wire through some of the vent holes, you may want to consider that to make your design more solid and also pop the wire out at different spots to make it more intricate. Potentially you can also drill your own holes in the helmet to create more options to weave your wire, but I chose not to do that in this build.
When you are happy with the design, you can glue it down. I used a hot glue gun and glued joints of the design. It looks a little bit ugly but it is relatively easy and effective. Perhaps yours can look nicer if you are careful with your work. It is also semi-permanent, so if you mess up you can always peel away the glue after it dries and try again. You can experiment with other types of glue or adhesives for your helmet.
After your wire is glued down and dried, hook your EL wire (2 end wires) to your inverter (2 black wires with a connector). It doesn't matter which wire is hooked up because it is AC current instead of DC. Then hook your red wire (vcc) to the 3.3V rail of the LaunchPad and black wire to SOURCE of the MOSFET. Hook the DRAIN to GND of the LaunchPad. Then hook the GATE pin of the MOSFET to one of the digital pins of the LaunchPad. Program you LaunchPad to toggle the digital pin you are connected to and you should see the EL Wire turn on and off. I used Energia to program the LaunchPad quickly, the code is below.
Plug in your battery source and now your helmet should be wireless. If you can have a power source with a switch that is best, so you can turn it off when not in use. Some AA battery packs and the Battery BoosterPack MKII have an on/off switch.
Now hide all your electronics inside of the helmet and you can turn it on. Sweet!
Once you build it the first time you will see ways you can do it better the next time, maybe you can start making them as gifts for your friends.
NOTE: the inverter makes a small, high pitched noise when powered on, this is normal and doesn't really bother you when wearing the helmet.
Improvements: Now that we have added a controller to the helmet, it wouldn't be too hard to go the next step and add a radio to the helmet so it can be controlled wirelessly. This would make a fun way to adjust your blinking effects with your phone or something.
The helmet will look best in a dark environment. You can pair with more LED based costumes for a very nice effect at night.
This project was inspired by Halloween. You can also check out the pumpkin I made using my MSP430 LED gizmo - tutorial here.