zondag 13 december 2020

Arduino Elecrow EL Shield

A long time ago i ordered on Aliexpress an Arduino EL-shield as it seemed interesting to play with it. Due to other priorities i never found time to play with it. When looking in my box with Arduino shields i decided to do a quick test. 

EL wire is flexible plastic wire that glows brightly when high-voltage AC is applied to it.

Numerous cool colors are available. They requires very little current, but it can be difficult to work with because of the high-voltage requirements. The Elecrow EL Shield enables you to implement up to 8 channels of EL wires or tapes in an Arduino  project to control the EL modules. 
The controlling method is as simple as controlling an LED. Driven by PWM, it can create a colorful and florid effect by controlling each EL wire according to your own programs.
With the shield 4 pieces of 2 meter are included The shield has 8 channels. See table below.

Pin

PINEL Channel to ControlPWM?(My Wire)
D2EL Channel A-
D3EL Channel BPWM( Blue )
D4EL Channel C-
D5EL Channel DPWM( Orange )
D6EL Channel EPWM( Green )
D7EL Channel F-
D8EL Channel G-
D9EL Channel HPWM( Yellow )


On the Arduino Uno Pin D3 D5 D6 D9 are PWM pins.
Therefore i decided to use these pins for the EL wires. ( Also tested the other channels on the EL shield and they all worked. However on D2 D4 D7 D8 there is no PWM )
When the EL wires are not powered and give no light the color is a bit different. I added in the table above the colors of my wires. 


The EL modules needs a driver voltage more than 110V, AC. The included Elecrow customized inverter can convert the 5V-DC input to AC,110~220V. 
Connected the inverter to EL-Shield as below:
The input wire of the inverter is red/white, which need to be inserted into the DC_5V terminal of EL Shield, and the output wire(black) of the inverter need to be inserted into the AC>110V termina
Specs say that can drive a max of 15m EL wires. 4 x 2 m = 8 meter EL wire was included so lighting them all up at the same is no problem.
As this is all the EL-wire i have i could net test adding additional EL-wire.

In the instruction ( https://www.elecrow.com/wiki/index.php?title=8-Channel_EL_Shield ) First the Arduino is connected to a computer and a script is uploaded. After that the Arduino is disconnected from the computer. The shield is plugged in and an external mains power supply is used. As there is a high voltage on the shield (also near to the Arduino USB connector) i think this is the best way to prevent damaging your computer.
For some applications it would be interesting to see how long this shield can run on a 9 volt battery.
The disadvantage is that you need to plug and unplug connections when playing with the EL-shield. It also makes testing and debugging Arduino programs for this shield a little more difficult. An option could be creating a test with leds connected to D2 to D9 or using an good opto-isolation in the USB to your computer.

When running programs like the provided test program the system emits some low volume beeps and a buzzing sound. It is not a loud noise however i think it is important to mention it. It is possible the sound depends on the amount of power used by the wires and that only 4 of the 8 wires are connected.

On the EL-shield is also a red power led.
// EXAMPLE PROGRAM FROM THE ELCROW WEBSITE
void setup(){
 for(int i = 2; i<10; i++)
 { 
  pinMode(i, OUTPUT);
 }
}
 
void setEL(int ch) // set a certain EL on
{ 
  for(int i = 2; i<10; i++) // all on
 digitalWrite(i, HIGH);
 delay(1000);
 for(int i = 2; i<10; i++) // all off
 digitalWrite(i, LOW);
  for(int i = 2; i<10; i++) // 
 {
  digitalWrite(i, HIGH);
  delay(200);
  digitalWrite(i, LOW);
 }
 } 
 
int count = 0; 
 
void loop()
{ 
 setEL(count%4 + 1);
 delay(200);
 if(count++ == 1000)
 { 
  count = 0;
 } 
}
 
( The % in the Arduino program above is the modulo operator : count%4 is 'counter modulo 4 ' )


Conclusion:
  • An interesting relative cheap Arduino shield.
  • The (2 meter long) EL-wires give an interesting light effect for a project. Perhaps for your project you will need another color or more wire of the same color. (I did not test other El-wires.)
  • Due to the high voltage generated by the 'Elecrow customized inverter' i did not want to take risks trying the EL-lights with the USB connected to my computer. A USB opto-isolator or a test shield with leds to D2 to D9 would be useful.

 






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