#define START_BUTTON_PIN 22  // ESP32 pin GPIO22 connected to start button's pin
#define STOP_BUTTON_PIN 21  // ESP32 pin GPIO21 connected to stop button's pin
#define RELAY1_PIN  27  // ESP32 pin GPIO27 connected to 1st relay's pin
#define RELAY2_PIN  26  // ESP32 pin GPIO26 connected to 2nd relay's pin
#define ACC_RELAY3_PIN  25  // ESP32 pin GPIO25 connected to 2nd relay's pin
#define ACC_RELAY4_PIN  33  // ESP32 pin GPIO33 connected to 2nd relay's pin
void setup() {
  Serial.begin(9600);                // initialize serial
  pinMode(START_BUTTON_PIN, INPUT_PULLUP); // set ESP32 pin to input pull-up mode
  pinMode(STOP_BUTTON_PIN, INPUT_PULLUP); // set ESP32 pin to input pull-up mode
  pinMode(RELAY1_PIN, OUTPUT);        // set ESP32 pin to output mode
  pinMode(RELAY2_PIN, OUTPUT);        // set ESP32 pin to output mode
  pinMode(ACC_RELAY3_PIN, OUTPUT);        // set ESP32 pin to output mode
  pinMode(ACC_RELAY4_PIN, OUTPUT);        // set ESP32 pin to output mode
}
void loop() {
  int StopButtonState = digitalRead(STOP_BUTTON_PIN); // read new state
  int StartButtonState = digitalRead(START_BUTTON_PIN); // read new state

  if (StartButtonState == LOW) {
    Serial.println("Start your engine");
    digitalWrite(ACC_RELAY3_PIN, HIGH); // turn on ACC relay 3
    digitalWrite(ACC_RELAY4_PIN, HIGH); // turn on ACC relay 4
    delay(500); // wait for .5 seconds
    Serial.println("Starting engine 1");
    digitalWrite(RELAY1_PIN, HIGH); // turn on relay 1
    delay(3000); // wait for 3 seconds
    digitalWrite(RELAY1_PIN, LOW);  // turn off relay 1
    delay(500); // wait for .5 seconds
    Serial.println("Starting engine 2");
    digitalWrite(RELAY2_PIN, HIGH); // turn on relay 2
    delay(3000); // wait for 3 seconds
    digitalWrite(RELAY2_PIN, LOW);  // turn off relay 2
  }
  if (StopButtonState == LOW) {
    Serial.println("Stop all engines");
    digitalWrite(ACC_RELAY3_PIN, LOW);  // turn off ACC relay 3
    digitalWrite(ACC_RELAY4_PIN, LOW);  // turn off ACC relay 4
    delay(300); // wait for .3 seconds
  }
}