int CSDPin = A0;
int std1 = 100;

void setup() {
  // put your setup code here, to run once:
  pinMode(12, OUTPUT); //buzzer output when alert
  pinMode(13, OUTPUT); //LED output

  pinMode(2, INPUT); //if alert switch set
  pinMode(4, INPUT); //if photoresister work
 
  Serial.begin(19200);
  Serial.println("Hi, Vincent");
}

void loop() {
  // put your main code here, to run repeatedly:
  //int resultA0 = digitalRead(CSDPin);
  int EnableResultD2 = digitalRead(2);
  int PhotoResistorRresultD4 = digitalRead(4);

  //for Ariduino UNO LED blink test
  digitalWrite(13, HIGH); //set LED blink
  delay(1000);
  digitalWrite(13, LOW);
  delay(1000);
  
 //read enable and photo resistor signals
  Serial.print("Enable: ");
  Serial.println(EnableResultD2);
  Serial.print("Photo resistor: ");
  Serial.println(PhotoResistorRresultD4);
  
  delay(1000);
 // if ( resultD2 >= 1)
  if ( ( PhotoResistorRresultD4 == 0 ) && (EnableResultD2 == 1 ) )
  {
    Serial.println("Alert");
    digitalWrite(12, HIGH); //set buzzer ON

  }

  if ( PhotoResistorRresultD4 == 1 )
  {
    Serial.println("Safe");
  }
}