#include <Servo.h>
Servo servo;
byte servoPin = 4;
byte buttonPin[] = { 2, 3, 5, 6, 7 };                         // declare button pins in an array
byte rgbled[] = { 8, 9, 11 };                                 // declare rgbled pins in an array
byte element;                                                 // indicates pressed button/pin
byte r, g, b, a;                                              // RGBLED colors and servo angle
byte buttonArray = sizeof(buttonPin) / sizeof(buttonPin[0]);  // get number of elements in button array
byte rgbledArray = sizeof(rgbled) / sizeof(rgbled[0]);        // get number of elements in rgbled array

unsigned long timer;          // timer keeps track of length of button press (or noise/ringing).
unsigned long timeout = 100;  // timeout (in milliseconds) is the minimum for "a button is pressed".

void setup() {
  Serial.begin(115200);                   // start serial monitor
  for (int i = 0; i < buttonArray; i++)   // count to number of elements in button array
    pinMode(buttonPin[i], INPUT_PULLUP);  // configure button pins for reading (LOW when pressed)
  for (int i = 0; i < rgbledArray; i++)   // count to number of elements in rgbled array
    pinMode(rgbled[i], OUTPUT);           // configure RGBLED pins
  servo.write(90);                        // park 360 servo at "STOP" (90 degrees for 180 servo)
  servo.attach(servoPin);
}

void loop() {
  if (element > buttonArray)                  // count through array... do not use for() loops. they blocking program flow.
    element = 0;                              // if beyond the array size, start again from the first element
  if (!digitalRead(buttonPin[element])) {     // button may have been pressed, or just noise/ringing
    if (millis() - timer > timeout) {         // measure time from last "press" to this "press. replaces delay();
      if (digitalRead(buttonPin[element])) {  // valid button was released after debounce timeout
        timer = millis();                     // reset timer after valid button press
        switch (element) {
          case 0: r = HIGH, g =  LOW, b =  LOW, a = 180; break; // red, r, fast
          case 1: r =  LOW, g = HIGH, b =  LOW, a = 135; break; // grn, r, slow
          case 2: r = HIGH, g = HIGH, b = HIGH, a =  90; break; // wht, stop
          case 3: r =  LOW, g =  LOW, b = HIGH, a =  45; break; // blu, l, slow
          case 4: r = HIGH, g = HIGH, b =  LOW, a =   0; break; // yel, l, fast
          default: break;
        }
        ledServo(r, g, b, a); // change RGBLED color and servo angle
      }
    }
  }
  element++;  // next array element
}

void ledServo(byte r, byte g, byte b, int angle) {
  digitalWrite(rgbled[2], r);
  digitalWrite(rgbled[1], g);
  digitalWrite(rgbled[0], b);
  servo.write(angle);
}