Introduction: Baby Tron Costume

For my son's first Halloween, I decided that he would be a "Hello World" program with a costume inspired by the movie Tron. The Tron costume uses reflective tape and electroluminescent wire (El-wire). The costume is controlled using a remote. 

Step 1: Materials

Non-electronic components:
White footed pajamas (choose one that does not have snaps down the middle)
White cap
Blue iron-on reflective tape (1" x 60")
Needle and thread
Iron and ironing board

Electronic components:
The following items were ordered from SparkFun:

EL Sequencer (SKU: COM-09203)
SparkFun Project Case - Black (SKU: WIG-08601)
Polymer Lithium Ion Batteries - 1100mAh (SKU: PRT-00339)
10 Jumper Wire - JST Black Red (SKU: PRT-08670)
Transceiver nRF24L01+ Module with Chip Antenna (SKU: WRL-00691)
Nordic FOB (SKU: WRL-08602)
LiPoly Charger - Single Cell 3.7-7V Input (SKU: PRT-00726)
FTDI Basic Breakout - 3.3V (SKU: DEV-08772)

The following items can be found at CooLight:
20 feet 3.2mm LYTEC - UM - UltraMarine (
IFW 3294 2K 3v

Step 2: Design

Before you begin. you will need to come up with a design for your costume. It is best to have the pajamas so that you can get a good feel for how much space you have to work with and how intricate you can be with your design. This will also help you determine how much EL
wire to buy.

You can start by simply sketching some designs on a piece of paper. Next, use pieces of string to lay the designs out on the pajamas. This will help you determine how long each segment of reflective tape will need to be.

Step 3: Adding the Reflective Tape

Now that you have a design, it's time to start cutting the reflective tape and applying it to the costume. I cut 1" wide reflective tape into 1/4" strips for the lines and traced the cap of a pen for the dots. Once you have several pieces cut out and ready, start ironing the pieces on. You must remove the clear backing from the tape, place onto the fabric, and iron on. Once cooled, there is another clear piece that must be pulled off. (Read the instructions on the package. You may also want to do a test run on another piece of fabric before starting on the costume.) Overlap joining pieces for a cleaner look and more sturdy finish. Overlapping pieces will need to be ironed on separately. You will need to iron on the first piece and remove the clear sheet on top before continuing with any joining pieces.

Step 4: Making the El-Wire

The approach that I take to any project is to prototype first, then refine the project in iterations.  After getting all the pieces in, I wanted to assemble a simple test.  This approach makes it easier to debug problems when things don't work quite right.  In order to test the El-Sequencer, you need

1) A power source
2) The El Sequencer
3) A strand of El-Wire

The first thing that you really need to assemble is the El-Wire.

Online you can find a number of tutorials on how to solder El-Wire. The most professional approach seems to be to use foil tape.  The two "angel" wires get bent back and soldered onto the foil tape which is wrapped around the wire casing.  I didn't use foil tape, but it would help to make the connection more durable. Instead, I followed the approach used by SparkFun on one of their El-Wire projects.

You can see in this picture the center wire covered in phosphor and the angel wires.  You should use shrink tubing on both wires so that you keep some isolation and provide extra strength.

Just like they did at Sparkfun, you should put an outer shrink wrap on it too.

The El Sequencer has JST connectors for both the power sources and the El-Wires. Because the El-wire is AC, it doesn't matter which wire you connect to which.  I tried to keep it consistent and put the black wire to the center.

Lastly, you need to solder two JST connectors onto the inverter. I used the IFW 3294 2K 3v inverter from Make sure to get the DC power going into the inverter correct.  The AC power coming out doesn't matter.  As I mentioned before, I like to keep all of the connectors consistent and would recommend that you do the same.

Step 5: Testing the El-Sequencer

Now that you have an El-wire built, you need to get a basic program on the El Sequencer.  I would recommend as a first pass that you download the El Driver example code from the El Sequencer product page that follows.

I used a 3.3V Ftdi basic board to put the code on the the AVR.  The El sequencer uses at Atmega168v.  I used Avrdude set to connect to an AVRISP2 to download the code to the board.  A bonus is that the board is powered from the Ftdi basic board as well.  The first test should light up the wire like so.

A video of the same first run follows. Now you are finally getting somewhere!!!

Step 6: Programming

The programming of the El-Sequencer is actually very simple.  You can turn each of the ports on one at a time, but you should ensure that more than one doesn't run at the same time.  The code in the EL-Driver package will give you a head start.  There are routines that keep only one line on and plenty of examples of what you can do with the programming lines.  

For the purposes of this costume, I wanted to have two different modes.  One that I call flutter that makes the links strobe and another called twinkle that makes the lines blink sequentially. Both routines are actually very similar, the delay between powering the different lines is the only thing that really changes.

The more complicated step was to add the wireless control.  The El-sequencer has a built in port for plugging in a Nordic RD link.  I thought that adding a remote control would round out the effect.  First, you need to download the NRF24L01 library from the following Sparkfun tutorial.

I would also look at the El-Sequencer code from the same page.  Keep in mind that the schematics have changes from 1.0 when that tutorial was built to 1.2 now.  The calls need to be modified to reflect the newer version of the El-Sequencer. 

On the other end of the wireless link, I used a Nordic Fob.  It gave me 5 buttons with different commands that would be sent over the wireless link.  Using the Nordic chips is actually pretty simple.  Once you get the timing right, one chips essentially sends a 3 element array over to the other device.  In this case, each of the five buttons sent a different value in the second slot of the array.  I built a loop that would read  the wireless register in a loop.  When it picked up a signal, it would fire off the routine that mapped to the button that was pressed. 

Step 7: Powering the Costume

I purchased two lithium polymer batteries to power the costume.  When I placed the order, I wasn't sure how quickly it would drain the battery and I wanted to have a spare battery.  One of the batteries is a 2000 MaH and the other is a 1100 MaH.  I decided to use the 1100 MaH battery.  After several tests, I found that it lasted in excess of 2 hours (intermittent, but frequent use).  

Just like the El-Wire and the inverters, you'll need to solder a JST connector onto it.  Its quite simple to do, and you should be a pro by now.

The other side to the equation is that you need to be able to charge the battery.  I decided to use the li-poly charger from Sparkfun, but not mount it in the device.  Since this was a one time use costume, I didn't plan on recharging it frequently.  If you already have a way to charge li-poly batteries, you don't need to purchase the one from the materials page.

Step 8: Packaging It Up

The final stage is to package it all up in something to protect the circuitry.  My original plan was to mount it in a frisbee on his back, similar to those from the movie Tron.  We decided against doing that because it became so large that he wouldn't be able to rest against it without hurting his back.  

The black Sparkfun case displayed below worked very well.  It was easy to mount all of the pieces.  You need to leave enough El-Wire hanging out to position the project case in a convenient location.  We used an extra 2 feet of wire so that it could be draped over our back when holding him in the costume.

The last thing that you need to do is add a switch to the battery. If you don't add a switch, you won't be able to turn off the device without unplugging the battery.  I picked up a cheap SPST switch from Radio Shack.  Any switch that can carry the DC 3.7V should work well.

Step 9: Finishing It Up

Once you have all of the electronics completed, it is time to finish the costume. Wrap the exposed ends of all of the wires with blue vinyl electrical tape. 

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