// https://forum.arduino.cc/t/resetting-or-zeroing-the-millis-at-end-of-each-cycle/1221287
// https://wokwi.com/projects/389172935034378241

// Pin definitions
const int relay1 = 53;  // Valve 4, Exhuast
const int relay2 = 51;  // Valve 3, Pressurize
const int relay3 = 49;  // Valve 2, Slide Movement
const int relay4 = 47;  // Valve 1, Chuck Movement
const int relay5 = 45;  // Valve 1, Chuck Movement

byte relayPin[] = {relay1, relay2, relay3, relay4, relay5};

byte NRELAYS = sizeof relayPin / sizeof *relayPin;

unsigned long aTimer;
unsigned long now;         // always millis() for the entire loop
const int INTERVAL = 333;  // step duration 

const byte R1 = 1;
const byte R2 = 2;
const byte R3 = 4;
const byte R4 = 8;
const byte R5 = 16;

byte relayBit[] = {R1, R2, R3, R4, R5};

byte sequence[] = {
  0,
  0,
  0,
  R1,
  R1 + R3,
  R1 + R3 + R5,
  R2 + R4,
  R1 + R3 + R5,
  R2 + R4,
  R1 + R3 + R5,
  R2 + R4,
  R1 + R3 + R5,
  R3 + R5,
  R5, 
  0,
  0,
  0,
  R1 + R2 + R4 + R5,
  R3,
  R1 + R2 + R4 + R5,
  R3,
  R1 + R2 + R4 + R5,
  R3,
  R1 + R2 + R4 + R5,
  0,
  0,
};

const int sequenceLength = sizeof sequence / sizeof *sequence;

void setup() {
  Serial.begin(115200);
  Serial.println("UA Sequencer V.0\n");

  for (int ii = 0; ii < NRELAYS; ii++) {
    pinMode(relayPin[ii], OUTPUT);
    digitalWrite(relayPin[ii], LOW);
  }
}

void loop() { 
  static unsigned long lastTime;
  static int step;

  now = millis();

  if (now - lastTime < INTERVAL) return;    // not time to do anything - use 1000 for real once a second loop, life too short

  lastTime = now;

  for (int ii = 0; ii < NRELAYS; ii++) {
    if (sequence[step] & relayBit[ii])
      digitalWrite(relayPin[ii], HIGH);
    else
      digitalWrite(relayPin[ii], LOW);
  }

  step++;
  if (step >= sequenceLength) step = 0;   // rinse and repeat
}