int sensorPin1 = 4;    // analog input pin for sensor 1
int sensorPin2 = 5;    // analog input pin for sensor 2
int sensorPin3 = 0;    // analog input pin for sensor 3  

int ledPin = 13;   // select the pin for the LED
int val = 0;       // variable to store the value coming from the sensor
int val2 = 0;       // variable to store the value coming from the sensor
byte val3 = 0;

int THRESHOLD = 100; // value 3 has an example threshold; if the received value is less than this, a 0 is sent to the serial port

void setup() {
  beginSerial(9600);
  pinMode(ledPin, OUTPUT);  // declare the ledPin as an OUTPUT
}

void loop() {

  val = analogRead(sensorPin1);    // read the value from the sensor
  val2 = analogRead(sensorPin2);    // read the value from the sensor
  val3 = analogRead(sensorPin3);    // read the value from the sensor
  
  if (val3 < THRESHOLD) { // gate level for the sensor
    val3 = 0;
  }
      
  printString("A");    
  printInteger(val); 
  serialWrite(10);
  
  printString("B");
  printInteger(val2); 
  serialWrite(10);

  printString("C");
  printInteger(val3);
  serialWrite(10);  

  delay(20);
}