// Code written by Hertz and Madden on 20/05/2021

const int SolenoidA = 10; // Connect the terminal 'A' of thesolenoid to Digital Pin 10 on the Arduino
const int SolenoidB = 11; // Connect the terminal 'B' of the solenoid to Digital Pin 11 on the Arduino
const int IRPin = 9; // Connect the output pin of the IR sensor to Digital Pin 9 on the Arduino
int IRstate = 0; // Set the initial state of the IR output as 0

void setup() 

{
  pinMode(13,OUTPUT); // Set the Digital Pin 13 as an output
  pinMode(SolenoidA, OUTPUT); // Set the Digital Pin 10 as an output
  pinMode(SolenoidB, OUTPUT); // Set the Digital Pin 11 as an output
  pinMode(IRPin,INPUT); // Set the Digital Pin 9 as an input
  digitalWrite(13,LOW);  // Set the status indicator LED to LOW
  digitalWrite(SolenoidA, LOW); // Set the solenoid valve to its OFF position
  digitalWrite(SolenoidB, HIGH); 
  delay(500);
}

void loop() 

{
IRstate = digitalRead(IRPin); // Read the output of the IR sensor and define it as IRstate

if(IRstate==HIGH){ // If the IR sensor detects an object within its range
  digitalWrite(13,HIGH); // Turn on the status indicator light
  digitalWrite(SolenoidA, HIGH); // Provide a positive pulse to the solenoid valve to open it
  digitalWrite(SolenoidB, LOW);
  delay(2000); // latch it for 2 seconds
}

else if (IRstate==LOW) // If the IR sensor doesn't detect an object in its proximity
{
  digitalWrite(13,LOW); // Turn off the status indicator light
  digitalWrite(SolenoidA, LOW); // Provide a negative pulse to the solenoid valve to close it
  digitalWrite(SolenoidB, HIGH);
  delay(1000); 
}
}