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The EL Escudo is an Arduino Compatible shield for controlling up to 8 channels of EL wire. Electroluminescent wire is this really neat, flexible cord that emits a florescent light which is sometimes referred to as 'cool neon' because the cord does not heat up. The kicker is that EL wire runs on high voltage AC - about 125V at 425Hz. While EL wire requires very little power, you can't use normal transistors to turn on/off a string of it. The EL Escudo was created to make it easy to interface EL wire to an Arduino board.
A device called an inverter is needed to generate the required AC voltage to power the EL wire. An inverter takes a DC input and outputs the required 125V AC to drive the electrolumincent wire. SparkFun has a 12V inverter that can be used to power your EL wire if you’re using a 12V power supply for your Arduino. You can find more information on the 12V inverter at this link:
12V Inverter for EL Wire
The first step is to plug the EL Escudo into your Arduino board. You'll need to solder in some headers with the male end of the pin facing down (or away from the components on the board), but then it should be pretty obvious which way the board needs to be plugged in. Make sure the Arduino board is not powered when you plug the EL Escudo into the Arduino. There will be 4 wires coming from your inverter; two of them are for the input power, and two of them will be the wires that output the AC signal. Connect the two wires for the input power to the pins on the EL Escudo labeled “Raw Voltage.” Connect the other two wires to the pins labeled “Output.” Once the hardware is connected the Arduino board can be powered.
This github project contains the code for the EL Escudo Arduino Library. To use the library, start by downloading the code and saving it in the 'libraries' folder in your Arduino directory. There are a couple example sketches included with the library, you can learn how to use the API by experimenting with those examples. One note to remember is that the channels are already defined by the library; using 'A' with a command will affect the EL Wire attached to channel 'A' o the EL Escudo. Here is a brief overview of the available commands in the API.
Description: Turns the specified EL channel on. Keep in mind that only two EL channels can be on at the same time unless the 'all_on' function is used.
Example: EL.on(A);
Description: Turns the specified EL channel off.
**Example:**EL.off(C);
Description: Turns all of the EL channels on. This is achieved by turning each channel on and off quickly in succession. This will only turn each channel on once, so to keep the EL wire on this function would need to be placed inside a while loop, or possibly inside a timer interrupt function.
Example: EL.all_on();
Description: Turns all of the EL channels off. Example: EL.all_off();
Description: Uses a manual PWM to fade an EL channel on, rather than the 'instant on' affect achieved by using the 'on' function. This function takes 500ms to execute, and the sketch won't continue to the next line until the operation has completed. The EL channel will be left on after the operation is finished, so make sure there is, at most, only one other channel turned on if this function is used.
Example: EL.fade_in(B);
Description: Uses a manual PWM to gradually dim and EL channel until it is off. This function takes 500ms to execute, and the sketch won't continue to the next line until the operation has completed. The EL channel will be left off after the operation is completed.
Example: EL.fade_out(E);
Description: Pulses an EL channel by fading the EL wire on, then off. This function will take approximately one second to complete, and the Arduino sketch won't continue to the next line until the operation has completed.
Example: EL.pulse(H);