EL Wire - Project Notes

I initially wanted to use EL Wire as an ambient notification device.  Blinky-lights demand attention usually, but a length of EL Wire inside a diffuse container -- well that can glow more subtly. Initially I bought a five-dollar lamp shade to put stuff in, but it was too thick to see through. I ended up using some plexiglass jewelry boxes and a translucent take-out style container to contain my EL Wires.

I'd purchased an "EL Wire Starter Kit" at defcon, which was pretty useless by itself, but did include a couple feet of EL Wire -- so there's that.  :)  But if you don't have any, you gotta get some:

I'm comfortable programming Arduino, and I like SparkFun's products, so I bought their "EL Escudo" shield.  Turns out it's very bare bones and I had to make a second trip to have enough parts for a working solution.

  • SparkFun EL Escudo Arduino shield.
  • A bunch of male JST connectors, since wire and power connect to the shield that way.
  • A small, cheap transformer to convert Arduino's DC power to high voltage AC for the wires.
  • Standard 0.1" headers, to add pins to the shield so it can attach to Arduino.
  • A few sizes of heat-shrink tubing, or some other way to insulate soldered, twisted-pair wires.
I got out the soldering gun and went to town.
  • Solder headers onto the shield.
  • Chop off the useless connectors on my EL Wire.
  • Solder JST connectors onto my EL Wire.
  • Solder JST connectors onto my transformer.
  • Hook it all together and say hello to the world.
Adding JST connectors to the EL wire is the most difficult part of the whole thing.  My stuff might just suck, or my eyesight might be going, but it was sneaky.  An EL wire (or at least mine) has several coaxial layers to it:
  • The outer, thick "color" plastic layer, just there to tint the glow.
  • An inner, clear, insulator.
  • Inside that, a super-thin conductor wire attached to one terminal of the AC
  • Which presses against an inner-inner layer of phosphor-something-material.
  • And the phosphor is directly coating a thick-ish central conductor, on the other AC terminal.
Wikipedia explains EL Wire structure better than I'll do here.

Soldering the core wire to a jumper wire on a JST connector is easy.  Strip down to it, scrape off the phosphor-y-stuff, and solder the wire to it.  But the outer wire is sneaky -- I ended up using an exacto to cut open the clear insulator, then kinda tease out the wire.  It breaks super easily.  Stay sober during this step!  There are knives and you have to remember the heat-shrink before you start soldering, and your eyesight needs to be clear to even see the second wire.

With the EL Wires all soldered to JST connectors, you're now free to have a little drinky-poo, or another mountain dew, or a glass of milk, or whatever.  You deserve it -- that outer wire was practically taunting you, by the end.

Now, solder the transformer to some JST connectors.  Easy, right?  Yep.  I have red-black wire on my JST connectors, so I just matched my colors to the transformer's colors on the input side.  The output side is two white wires, and it's AC, so attach 'em any old way to the red-black wires on your JST connector.

The EL Escudo is nicely labeled.  Just connect stuff where it says to on the shield.  And attach the shield to your Arduino.  And connect it to your computer with a USB cable.  Arduino will wake up, and probably not do anything interesting.  SparkFun has an Arduino library for the EL Escudo, and two example sketches, so let's make it say hello, world.
  • Download the EL Escudo Arduino library.
  • Unzip it and put the EL_Escudo folder in your arduino/libraries folder.
  • Quit out of all your Arduino windows, if it's currently running.
  • (Re)Open Arduino.  In the "File" menu, select "Examples," then "EL_Escudo" and then "EL_Blink."
  • In the "Tools" menu, under "Serial Port," make sure it's talking to your Arduino's serial port.
  • And now in the "File" menu, simply "Upload to I/O Board" and away you'll go.
Your Arduino will now use the EL Escudo shield to turn on each attached EL wire, in turn, one at a time.  Fun, huh?  Yeah!  Pop back into the Arduino software and change the delay() values around, and comment out the ports on the shield you're not using.  Next, try the EL_Fade example -- it's super-rudimentary PWM, and also shows how you can use a for() loop to iterate through the channels one at a time, which is a useful trick.

Now what?  Well, you're kinda looking at it.  The EL Escudo has some caveats that merit mentioning:
  • It can only reliably power one wire at a time, or two reeely short ones.
  • It gets confused easily.  I recommend using EL.all_off() at the start of your loop(), not just setup().
  • The shield has lots of exposed AC wiring.  You're gonna zap yourself.  Laughter is the best medicine for a 125 volt (but very few amps) jolt.  :)
  • Your friends are gonna be impressed.  Nothing says 'leet, like a finished project that glows!
I had fun with a few different materials, while I was playing:
Next up for me?
  • Teach my glowing take-out container to take instructions over USB from a Processing app.
  • Connect a Processing app to iCal/email/twitter and do some ambient notification.
  • Follow Jeri Ellsworth's EL Wire DIY instructions and make my own EL Wire.
  • Illuminate a motorcycle jacket?
  • Remind myself of early meetings before I leave the house?
  • Tell me the weather forecast?