Dimming EL Wire




Electroluminescent wire is a thin copper wire coated in a phosphor, which glows when an alternating current (100V) is applied. Unlike a LED strip it’s not a series of point but an unbroken line of visible light in all 360 degrees. The brightness of this technique is sufficient for the application and because of the very flexible nature of this material it can be easily incorporated in many different applications.

In this instructable I will explain how to apply fade effects to EL-Wire.

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Step 1: Possible Techniques

Electroluminescent wire is not easily adjusted in brightness, therefore fading in and out is hard. Two main techniques are used to change the brightness of the electroluminescent wire, one is based on a custom build driver that actually shifts electroluminescent wire brightness by changing the alternating current frequency. The other is based on the same mechanism and uses a 555-timer component to change the current frequency, but this version is a lot simpler.

A problem with changing the frequency is the color change in the electroluminescent wire, above the 2000Hz the wire will quickly change to a lighter color, for example from dark blue to aqua blue. This behavior is not desirable in my application, but a slow fade effect to show the user the device is in progress is.

link to tutorial with 555-timer: http://hackaday.com/2011/07/13/color-changing-el-wire/

next step how does it work

Step 2: How Does It Work

I figured out that a standard supplied 3V EL-wire inverter is capable of handling a quite large range of input voltages from 2.5V till 3.5V.

Testing with a variable power supply showed a very nice color change of the electroluminescent wire and also showed that the inverter is capable of handling much lower voltages to completely fade out the electroluminescent wire. The next task was developing a variable power supply which can be adjusted with an Arduino.

Step 3: What Do You Need?

I ordered all my supplies at sparkfun. You are free to choose your own supplier.

This was my shopping cart

EL Inverter - 3v
COM-10201                                                https://www.sparkfun.com/products/10201

EL Wire - of your favourite color 3m
COM-10194                                                https://www.sparkfun.com/products/10194

COM-09234                                                https://www.sparkfun.com/products/9234

Voltage Regulator - Adjustable
COM-00527                                                https://www.sparkfun.com/products/527

Step 4: Schematic of Variable Power Supply

The schematic of this board can be found in the photos. The technique is based on a variable power supply component LM317, which can adjust the voltage based on the ratio between to external resistors, by shortcutting one of these resistors with a pulse width modulation signal, it is possible to change the output voltage of this component and thus change the brightness of the electroluminescent wire.

I connected 2 inverters to one arduino nano to control my El-wire

See also the LM317 calculator:

Step 5: Arduino Code

Copy this code to your arduino and if necessary make some adjustments.
I tried to be as complete as possible with my comments please ask if something is not clear.

int counter = 0; // to count how many instances the fade loop has made
int pwmPin = 9; // adjustable voltage on pin 9
int greenELwire = 4; //connect the blue ELwire FET to pin 4 to turn it on and off
int blueELwire = 5; //connect the green ELwire FET to pin 4 to turn it on and off
void setup() {
// nothing happens in setup
void loop() {
// fade in from min to max in increments of 5 points:
digitalWrite(blueELwire,LOW);// explicitly turn off all ELwire
delay(2500); //wait 2.5 seconds
digitalWrite(greenELwire,LOW); // green off
digitalWrite(blueELwire,HIGH); // blue on
//start fading on pwmPin
while(counter < 8){//fade in and fade out 8 times
for(int fadeValue = 00 ; fadeValue <= 200; fadeValue +=1) {
// sets the value (range from 0 to 200):
analogWrite(pwmPin, fadeValue);
// wait for 6 milliseconds to see the dimming effect
delay(6); // total duration of fade is 200*6 = 1200ms or 1.2
// fade out from max to min in increments of 5 points:
for(int fadeValue = 200 ; fadeValue >= 00; fadeValue -=1) {
// sets the value (range from 0 to 255):
analogWrite(pwmPin, fadeValue);
// wait for 30 milliseconds to see the dimming effect
//total time of fade in and out is 1.2 seconds times 2 = 2.4 seconds which is a slow
counter++; // increment the counter so the fading stops after 8 instances.
analogWrite(pwmPin,0); // make the pwmPin 0 so the fading stops and the ELwire will be on
full brightness.
digitalWrite(greenELwire,HIGH); //blue off (low is off)
digitalWrite(blueELwire,LOW); // green on
delay(5000); //wait 5 seconds to show the user the treatment is completed
counter = 0; // make counter 0 after 8 instances

Step 6: Done

You are done!

check if everything works!

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    15 Discussions


    Question 1 year ago

    Would it not be easier to use a mosfet connected to the pwm pin to change the output going from the battery to the el wire inverter?


    3 years ago

    Hi rikkkurd
    I'll try to build this with your instructions but for a beginner like me it would be very helpful to have a more detailed list with all parts like resistors, diodes and switches, ... Would it be possible for you to give me a more detailed list? Or do you have found a new way in the last two years to improve something?

    2 replies

    Reply 3 years ago

    Hi claudio,

    I did not find an improvement on this design yet. But it works very well. All parts are annotated in the schematic https://cdn.instructables.com/FYF/BY1S/HMMF949D/FYFBY1SHMMF949D.MEDIUM.jpg which is also in the instructable. As a beginner it can be difficult to start such a project but i definitely believe you can pull it off. If you have any questions please let me know. i believe all parts used are still easy to get an hold on. Best, rik


    Reply 3 years ago

    Thank you for your response! I am really happy that you answer my beginner questions :). I'm back with some questions:

    1. I can't find all components of your shopping list in your schematic:

    EL Inverter - 3v / COM-10201 = ???
    EL Wire = ???
    TRIAC - COM-09234 - MAC97A4 = BC550?
    Voltage Regulator COM-00527 = LM317?

    2. Are the two LED's (LED1 Blue 470nm, LED2 Green 555nm) necessary? Is the exact wavelength important for the dimming function?

    3. What's the difference between BS170 and BS171?

    4. What changes would be necessary if I want to power the el-powercircuit with a 3.7V lipo-battery instead of the 9V battery? Like this one: https://www.sparkfun.com/products/8483

    I know these are maybe very idiotic questions but I hope you have some free minutes to help me out with them :D


    4 years ago

    Hi, ridddurd.

    This tutorial is very useful and easy to implement. And also your statement is clear.

    I have one question about the schematic. In the schematic, Arduino D9 is pluged into some transistor(maybe).

    Please tell me about the detail of this component.

    4 replies

    Reply 4 years ago

    it's the triac https://www.sparkfun.com/products/9234
    sorry I was unclear about this, the parts list is in the first step.

    Hope I could help


    Reply 3 years ago

    you did not mention all parts on the list, because in the schematic you are using more parts....can you show more pictures in detail about arduino pro mini?


    Reply 4 years ago

    Great let me know if it works out im probably going to rebuild it myself as well upcoming month

    Matthew JamesD

    4 years ago

    can the speed of the fade effect be made slower?


    4 years ago on Introduction

    Hi. What is the simplest way to fade-in on power ON and fade-out on power OFF? Actually I do not need any arduino compatibility, just fading on power ON/OFF. Thank you.

    1 reply

    Reply 4 years ago on Introduction

    hmm interesting, A small arduino is still very simple, however what the arduino does is changing the supply voltage over time. if you have a big enough capacitor maybe it could slow down the rise of the voltage level and when powered down slowly fade out on the energy still available in the capacitor. No idea if this can work. if you do it by hand you can use a simple potmeter as a pwm output to use on the triac and switch it off by slowly turning the knob till you reach maximum brightness. Any people with other ideas?


    5 years ago on Introduction

    Can this set-up be used on a costume? Or does it have to be hooked up to a PC in order to (slowly) fade in and out?

    1 reply

    Reply 5 years ago on Introduction

    It can be definitly be used on a costume the arduino nano will handle all the fading and a simple 9v battery will be enough to power 1 meter for a few hours.


    5 years ago on Introduction

    Pulse with modulation applied on the output of the supply with a triac ( and arduino ) can give nice fade effects on multiple el wires. Perhaps I should write it up for instructables if I can find the time, but with the above hints you can probably figure it out.