Introduction: EL Driver Board

By Electric Stitches
Previously, I made a homebrew EL wire driver to be used with a LilyPad Arduino  (https://www.instructables.com/id/Programmable-LilyPad-EL-Wire-Dress/).  We at Electric Stitches (and with the help of iNMOJO) designed and made a pretty snappy looking sewable EL Driver available here: http://bit.ly/q4DnXP.  The board, used in tandem with the LilyPad, will give you control of the EL wire and allow you to flash and fade the strands of light in response to any input to the LilyPad.  And, with a bit of code, you can create beautiful patterns and illuminated lines as you strut your wearable down the street!

As this is an OSHW board please feel free to download the designs from: http://electricstitches.com/



EL Wire can be dangerous and can give you a mild shock. We have taken an extra step and added conformal epoxy coating to help prevent unintended shocks

Step 1: Materials

For this project you will need:
Total Cost: $40

Step 2: EL Driver Board

The EL Driver Board is an open source hardware project and you should feel free to download the eagle files from electricstitches.com. The board has 5 JST housing and 5 holes large enough for several loops of conductive thread.  Each hole and JST housing is labeled in blue.  AC-O is the JST housing where you should connect the AC Output of the inverter and DC-I is the JST housing where you should connect the DC Input of the inverter.  Additionally, you will sew plus to plus and minus to minus from the LilyPad Arduino to the EL Driver Board; the EL Driver Board shares power with the LilyPad and can thus power the inverter.

The circuit for the board is quite straightforward.  The triac switches power between the JST housing/EL Wire and the inverter.  When the gate of the triac is pulled, high current can flow and the EL Wire is powered.

Additionally, we have added a conformal epoxy coating on the board to help prevent unintended shocks.

Step 3: Attaching JST Cables

Using a "third hand" you can easily modify your inverter cables and add JST cables so that your inverter plugs into the EL Driver board.  Most inverters will have labels indicating which wires receive DC power as an input and which wires output an AC signal.  Often the power input wires are red and black (red is positive and black is negative).  Start by trimming and stripping a bit of  the power lines.  Next, "tin" (add a bit of solder) to the exposed wire.  Insert both wires into a piece of heat-shrink tubing.  Then insert just the black wire into a smaller-diameter piece of heat-shrink tubing.  Now you are set to solder on your JST cable.

Start by trimming, stripping and tinning the wires of the JST cable.  Line up the two black wires and solder together.  Slide the heat-shrink tubing over the solder join and shrink the tube with your soldering iron.  (I find it best to use are large part of the iron, not the tip, and keep the iron moving of the tube.)  Repeat again with the red wires and slip the tubing over both sets of wires.

Repeat this same process for the AC output wires.  (Note: for AC output it doesn't matter which wire is soldered to the black or red wire of the JST cable.)

To attach JST Cables to EL wire, please see LadyAda's excellent tutorial

Step 4: Sewing and Planning

With your inverter finished you are ready take a moment to think about your design. As always, plan out what you are going to sew.  Chalk is the seamstress/seamsters' lovable/washable/erasable friend. 

For my design, I wanted 3 nested blue lighting bolts. Having chalked out the first lightning bolt, I connected the power pins (+ to + and - to -) of the LilyPad and the EL Driver.  I then connected my inverter inserting the DC input line to the DC-I labeled jack and the AC output line to the AC-O jack.  I then tacked down the inverter cables with some invisible thread.


Step 5: Example Code

I've attached the code I used in the video to help you get started. I would suggest thinking about interesting ways to control the EL wire: sound input, button input, etc. and different patterns: flashing, fading, etc.  Have fun!

You can purchase EL Driver boards from http://electricstitches.com/

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