#define relayPin      7
#define pressureInput A0

int flag = 0;
const int pressureZero = 102.4; //analog reading of pressure transducer at 0psi
const int pressureMax = 921.6; //analog reading of pressure transducer at 100psi
const int pressuretransducermaxPSI = 100; //psi value of transducer being used
float bar = 0;
float pressureValue = 0; //variable to store the value coming from the pressure transducer

void setup() {
  Serial.begin(9600);
  pinMode(relayPin, OUTPUT);
  pinMode(pressureInput, INPUT);
  digitalWrite(relayPin, LOW);
  delay(5000);
}

void loop() {
  readSensor();
  if (pressureValue >= 6) {
    digitalWrite(relayPin, LOW);
    Serial.println("6 PSI****************************");
  }
  else if (pressureValue < 1) {
    digitalWrite(relayPin, HIGH);
  }
}


void readSensor() {
  pressureValue = analogRead(pressureInput);
  pressureValue = ((pressureValue - pressureZero) * pressuretransducermaxPSI) / (pressureMax - pressureZero);
  pressureValue = pressureValue + 0.6;
  if (pressureValue < 0.5) {
    pressureValue = 0;
  }
  Serial.print(pressureValue, 1);
  Serial.print("psi\t");
  bar = pressureValue / 14.5037738;
  Serial.print(bar, 1);
  Serial.println(" bar");
  delay(250);
}