Fading Arduino RGB LED from one color to the other?

Question

I\'ve currently managed to get my LED to cycle through eight colors that I\'ve selected. Everything is working correctly, except that I want to go for a more natural feel, and w

Answer 1

I would like to contribute with a more user friendly answer as aids understanding of how it works.

In my example bellow I'm using common anode RGB LED.

In my project however: To set a Color to RGB LED, I send a String via HW Serial.

Command Example: RGB000255000

This Command as String is divided into 4 parts of 3 chars each. Using the Command Example Above:

• "RGB" : To filter where the Command will be executed.
• "000" : The 2nd 3 Chars represent Red Value.
• "255" : The 3rd 3 Chars represent Green Value.
• "000" : The 4th 3 Chars represent Blue Value.

Result: This will Output Green on your LED.

See Code Bellow:

// Set your LED Pins.
const int rPin = 9;
const int gPin = 10;
const int bPin = 11;

// Set the variables that will assign a value to each Color Pin.
int rVal = 255;
int gVal = 255;
int bVal = 255;

// Fade Red Pin (In / Out).
void FadeRed(int red)
{
  // When Red Value on Red Pin is Inferior to the New Value: Fade In.
  if (rVal < red)
  {
    // Fade Out.
    for (int r = rVal; r <= red; r++)
    {
      // Set the Variable and Pin values.
      rVal = r;
      analogWrite(rPin, rVal);

      // Delay Slighlty (Synchronously). For Asynchronous Delay; you may try using "millis".
      delay(6);
    } 
  }

  // When Red Value on Red Pin is Superior to the New Value: Fade Out.
  else
  { 
    for (int r = rVal; r >= red; r--)
    {
      rVal = r;
      analogWrite(rPin, rVal);
      delay(6); 
    }
  }
}

// Fade Green Pin (In / Out).
void FadeGreen(int green)
{
  if (gVal < green)
  {
    for (int g = gVal; g <= green; g++)
    {
      gVal = g;
      analogWrite(gPin, gVal);
      delay(6);
    }
  }
  
  else
  { 
    for (int g = gVal; g >= green; g--)
    { 
      gVal = g;
      analogWrite(gPin, gVal);
      delay(6);
    }
  }
}

// Fade Blue Pin (In / Out).
void FadeBlue(int blue)
{
  if (bVal < blue)
  {
    for (int b = bVal; b <= blue; b++)
    {
      bVal = b;
      delay(6);
      analogWrite(bPin, b);
    }
  }
  
  else
  {
    for (int b = bVal; b >= blue; b--)
    {
      bVal = b;
      delay(6);
      analogWrite(bPin, b);
    }
  }
}

void FadeColor(int red, int green, int blue)
{
    // Debug Only.
    Serial.println("\n[+] Received Values");
    Serial.println(red);
    Serial.println(green);
    Serial.println(blue);

    // Code.
    FadeRed(red);
    FadeGreen(green);
    FadeBlue(blue);

    // Debug Only.
    Serial.println("\n[+] Pin Values \n");
    Serial.println(rVal);
    Serial.println(gVal);
    Serial.println(bVal);
}

/* Set RGB LED Color According to String Value. (i.e: RGB000000000) */
void SetColor(String color)
{  
  // Retrieve the New Color from String.
  /* Split a String : Start Position; End Position */
  String red = color.substring(3, 6);   /* Get the 1st 3 Characters Corresponding to RED   */
  String green = color.substring(6, 9); /* Get the 2nd 3 Characters Corresponding to GREEN */
  String blue = color.substring(9, 12); /* Get the Last 3 Characters Corresponding to BLUE */

  int r = atoi(red.c_str());
  int g = atoi(green.c_str());
  int b = atoi(blue.c_str());

  int redVal = 255 - r;
  int grnVal = 255 - g;
  int bluVal = 255 - b;
  
  FadeColor(redVal, grnVal, bluVal);
}


void setup()
{  
  pinMode(rPin, OUTPUT);
  pinMode(gPin, OUTPUT);
  pinMode(bPin, OUTPUT);

  pinMode(rPin, HIGH);
  pinMode(gPin, HIGH);
  pinMode(bPin, HIGH);

  analogWrite(rPin, rVal);
  analogWrite(gPin, gVal);
  analogWrite(bPin, bVal);
}