int button = 9;
long debounce = 500;               // the debounce time
long time = 0;
int buttonCount = 0;
int DPlus1 = 5;
int DPlus2 = 4;
int DMinus1 = 3;
int DMinus2 = 2;
int RLED = 6;
int GLED = 7;
int BLED = 8;
int vRead;
unsigned long previousMillis = 0;

void setup() {
  pinMode(button, INPUT_PULLUP);
  pinMode(RLED, OUTPUT);
  pinMode(GLED, OUTPUT);
  pinMode(BLED, OUTPUT);
  //  Serial.begin(9600);

  //  Serial.println("5v"); //button isn't trigger when powered on, so set for 5v in setup
  pinMode(DPlus1, INPUT);
  pinMode(DPlus2, OUTPUT);
  pinMode(DMinus1, INPUT);
  pinMode(DMinus2, INPUT);
  digitalWrite(DPlus2, HIGH);

  digitalWrite(RLED, HIGH);  //Write these high to avoid them turning on before vRead can assess
  digitalWrite(GLED, HIGH);
  digitalWrite(BLED, HIGH);
}

void loop() {

  if (millis() - previousMillis >= 500) {  //check vcc through divider; set LED accordingly
    previousMillis = millis();

    int vRead = analogRead(A0);

    if ((vRead >= 350) && (vRead <= 450)) {
      analogWrite(GLED, 200);
      digitalWrite(BLED, HIGH);
      digitalWrite(RLED, HIGH);
    }
    if ((vRead >= 451) && (vRead <= 750)) {
      digitalWrite(GLED, HIGH);
      digitalWrite(BLED, LOW);
      digitalWrite(RLED, HIGH);
    }
    if ((vRead >= 890) && (vRead <= 970)) {
      digitalWrite(GLED, HIGH);
      digitalWrite(BLED, HIGH);
      digitalWrite(RLED, LOW);
    }

  if (((vRead >= 451) && (vRead <= 750)) && (buttonCount == 2)){  //case where 12v is not supported, but 5v and 9v are
    buttonCount ++;
    }
  }
  if (digitalRead(button) == LOW && millis() - time > debounce) {  //Pushbutton for voltage switching
    buttonCount++;
    if (buttonCount >= 4) {         //Change based on supply modes available
      buttonCount = 1;
    }
    time = millis();
  }
    if (buttonCount == 1) {      //since we set the 5v in setup()
      DPlus_three_v_three();     //9v on first press
      DMinus_sixhundred_mA();
    }

    else if (buttonCount == 2) {  //12v
      DPlus_sixhundred_mA();
      DMinus_sixhundred_mA();
    }

    else if (buttonCount == 3) {  //5v
      DPlus_sixhundred_mA();
      DMinus_GND();
    }
  }

//Collection of pin states required for voltage dividers
void DPlus_sixhundred_mA() {
  pinMode(DPlus1, INPUT);
  pinMode(DPlus2, OUTPUT);
  digitalWrite(DPlus2, HIGH);
}
void DPlus_three_v_three() {
  pinMode(DPlus1, OUTPUT);
  pinMode(DPlus2, OUTPUT);
  digitalWrite(DPlus1, HIGH);
  digitalWrite(DPlus2, HIGH);
}
void DMinus_GND() {
  pinMode(DMinus1, INPUT);
  pinMode(DMinus2, INPUT);
}
void DMinus_sixhundred_mA() {
  pinMode(DMinus1, INPUT);
  pinMode(DMinus2, OUTPUT);
  digitalWrite(DMinus2, HIGH);
}
void DMinus_three_v_three() {
  pinMode(DMinus1, OUTPUT);
  pinMode(DMinus2, OUTPUT);
  digitalWrite(DMinus1, HIGH);
  digitalWrite(DMinus2, HIGH);
}