SRF05

long duration[2];
float distance[2];
int ECHO_PIN[2] = {4, 15};
int TRIGGER_PIN = 5;

void setup() {
  Serial.begin (9600);
  pinMode(TRIGGER_PIN, OUTPUT);
  pinMode(ECHO_PIN[0], INPUT);
  pinMode(ECHO_PIN[1], INPUT);
}

void loop() {
  digitalWrite(TRIGGER_PIN, LOW);  // Added this line
  delayMicroseconds(2); // Added this line
  digitalWrite(TRIGGER_PIN, HIGH);
  delayMicroseconds(10); // Added this line
  digitalWrite(TRIGGER_PIN, LOW);
  for (int x = 0; x < 2; x++) {
    duration[x] = pulseIn(ECHO_PIN[x], HIGH);
    distance[x] = (duration[x] / 2) / 29.1;
  }
  Serial.print("SRF Module_1 = ");
  Serial.print(distance[0]);
  Serial.print(" cm\n");
  Serial.print("SRF Module_2 = ");
  Serial.print(distance[1]);
  Serial.print(" cm\n");
  delay(1000);
}