Arduino LED sync and speed issues

Using Arduino Project Guidance
1

I've put together a circuit to control two LEDS (datasheet) with two Picobuck PED drivers (product page , datasheet ) controlled by an Arduino nano clone. I'm powering the Picobucks and Nano with a 12v 5A power supply, Fritzing sketch attached. (EDIT: there's a 10uf cap on the power to the Picobuck and Nano)

Lamp LEDs nano_bb
Lamp LEDs nano_bb1920×883 111 KB

The setup gradually changes the LED colour in a loop, but for some reason the speed of transition has become much faster (like less than a second) than the expected programmed rate (over 20 seconds). It does this occasionally from startup when the power is turned on, but not always. I am wondering if this is somehow a coding or hardware issue?

Additionally, when working correctly, the colour changes of the two LEDs are not synchronised and appear to be at different rates. Is this a coding issue?

Furthermore the two LEDs, even though identical and driven by identical drivers, have a marked difference in brightness. Could this be a limitation of the circuit?

Code attached.

const int redPin = 6;
const int greenPin = 5;
const int bluePin = 3;
const int redPin2 = 11;
const int greenPin2 = 10;
const int bluePin2 = 9;

void setup() {
  setColourRgb(0,0,0);
}

void loop() {
  unsigned int rgbColour[3];

  rgbColour[0] = 255;
  rgbColour[1] = 0;
  rgbColour[2] = 0;  

  for (int decColour = 0; decColour < 3; decColour += 1) {
    int incColour = decColour == 2 ? 0 : decColour + 1;

    for(int i = 0; i < 255; i += 1) {
      rgbColour[decColour] -= 1;
      rgbColour[incColour] += 1;
      
      setColourRgb(rgbColour[0], rgbColour[1], rgbColour[2]);
      delay(75);
    }
  }
}

void setColourRgb(unsigned int red, unsigned int green, unsigned int blue) {
  analogWrite(redPin, red);
    analogWrite(greenPin, green);
      analogWrite(bluePin, blue);
  analogWrite(redPin2, red);
  analogWrite(greenPin2, green);
  analogWrite(bluePin2, blue);

 }

Thanks for any advice!

2

The wiring looks odd. Can you post the link to the pic buck.

3

There's a hyperlink to the product page plus the datasheet for the AL8805 step-down DC/DC converter the Picobuck utilises in the original post.

4

You can check coding issues by using the serial monitor and adding serial prints in strategic places. I don't have your hardware but by doing that I can see that your outer for-loop runs at about 19000 milliseconds and your inner for-loop at about 75 milliseconds.

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Your topic has been moved to a more suitable location on the forum. Installation and Troubleshooting is not for problems with (nor for advise on) your project :wink: See About the IDE 1.x category.

5

Links to sales sites telling the price is not a link to the data sheet. Helpers like to use their time for thinking, not digging. You do the digging.

6

Sails sites?

1200×800 257 KB

Data sheet?

7

Yeah. Sites like that shows no engineering data..

8

Sales maybe...?

9

:+1:

11

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