Fade LED's slowly without delay

Projects Programming
1

Sorry if this question is basic, I am pretty new to coding. I am trying to fade 4 different colors of Cree LED's using LDD drivers (http://www.meanwell.com/search/LDD-H/LDD-H-spec.pdf) at different rates and times slowly to simulate sunrise, sunset, etc. I do not want to use delay because I will also have sensors displaying data on a LCD screen. I found the arduino-LEDFader (GitHub - jgillick/arduino-LEDFader: An arduino library to fade individual LEDs in the background without blocking your main program.) library that can fade without delay but I cannot easily find a way to do it over a long period of time. I tried starting with just one color and tried to fade it over 10 minutes but can only get a maximum of about 10 seconds in one command. I figured I could do it incrementally like in the code below; this fades over a minute but could be increased 10X to be over 10 minutes:

#include <LEDFader.h>

/*
  Fades a single LED up and down using LED Fader.
  Connect an LED to pin 3
*/

#define LED_PIN 11

#define FADE_TIME 10000

#define DIR_UP 1
#define DIR_DOWN -1

LEDFader led;
int direction = DIR_UP;

#include <Wire.h>
#include "RTClib.h"

RTC_DS1307 rtc;

void setup() {
  led = LEDFader(LED_PIN);
  Serial.begin(57600);
#ifdef AVR
  Wire.begin();
#else
  Wire1.begin(); // Shield I2C pins connect to alt I2C bus on Arduino Due
#endif
  rtc.begin();

}

void loop() {
  led.update();
      DateTime now = rtc.now();
    
    Serial.print(now.year(), DEC);
    Serial.print('/');
    Serial.print(now.month(), DEC);
    Serial.print('/');
    Serial.print(now.day(), DEC);
    Serial.print(' ');
    Serial.print(now.hour(), DEC);
    Serial.print(':');
    Serial.print(now.minute(), DEC);
    Serial.print(':');
    Serial.print(now.second(), DEC);
    Serial.println();
    
 if (now.hour() == 13 & now.minute() == 31 & now.second() == 0) {
         led.fade(40, FADE_TIME);
 }
 if (now.hour() == 13 & now.minute() == 31 & now.second() == 10) {
         led.fade(80, FADE_TIME);
 }
 if (now.hour() == 13 & now.minute() == 31 & now.second() == 20) {
         led.fade(120, FADE_TIME);
 }
 if (now.hour() == 13 & now.minute() == 31 & now.second() == 30) {
         led.fade(160, FADE_TIME);
 }
 if (now.hour() == 13 & now.minute() == 31 & now.second() == 40) {
         led.fade(200, FADE_TIME);
 }
 if (now.hour() == 13 & now.minute() == 31 & now.second() == 50) {
         led.fade(240, FADE_TIME);
 }
}

This is obviously a repetitive way of doing this but cannot figure out a better way to write the code. Can anyone help me with a more condensed method for this code.

2 
long previousMillis = 0;     
byte fade_count = 0;
long interval = 1000;           // how many ms between next fade . 

void setup()
{

}
void loop()
{

unsigned long currentMillis = millis();
 
  if(currentMillis - previousMillis > interval) { 
    previousMillis = currentMillis;   
    fade_count ++ ;    
  }

if ( fade_count > 5 )   // after how many steps fading is back to start position. Here no of steps is 5 .
{
  fade_count = 0;
}

switch ( fade_count )
{
  case 1:
  led.fade(40, FADE_TIME);
  break;
  
  case 2:
  led.fade(80, FADE_TIME);
  break;
  
  case 3:
  .....
  break:
}
}

This is based on blink without delay. It's not tested but you should get the idea. Jus set the interval and number of steps for fading .

3

I'd probably use a 8.24 fixed point format in a 32 bit unsigned integer, adding a fraction each clock tick.
The top eight bits would be fed directly to analogWrite.