LED fade with LDR sensor depending on the light
While some parts of your code don't make much sense to me, the breathing led code is easily searchable on the internet, with one of the first results being:

#include &lt;math.h&gt;
#define ledPin 11 
int i=0;
int breathe_delay = 15;   // delay between loops
unsigned long breathe_time = millis();
void setup() { }
void loop() {
  nonBlockingBreath();  // call the nonblocking function
  // yourOtherCodeHere();
}

void nonBlockingBreath() {
  if( (breathe_time + breathe_delay) &lt; millis() ){
    breathe_time = millis();
    float val = (exp(sin(i/2000.0*PI*10)) - 0.36787944)*108.0; 
    // this is the math function recreating the effect
    analogWrite(ledPin, val);  // PWM
    i=i+1;
  }
}


As you can see the code above works for monochromatic LEDs only, so my advise is to combine the code above with a conversion from HSL to RGB, like RGBConverter library, specifically the hsvToRgb function.

This way your version of the nonBlockingBreath function will become:

byte[3] rgb;
void nonBlockingBreath() {
  if( (breathe_time + breathe_delay) &lt; millis() ){
    breathe_time = millis();
    float value= (exp(sin(i/2000.0*PI*10)) - 0.36787944)*108.0; 
    hsvToRgb(hue, saturation, value, rgb);
    analogWrite(RedLED, rgb[0]);  // PWM
    analogWrite(GreenLED, rgb[1]);  // PWM
    analogWrite(BlueLED, rgb[2]);  // PWM
    i=i+1;
  }
}


Obviously you will have to set the hue and saturation variables accordingly to the tonality of orange you wish to breath.