authMicroprocessorsAndPeripherals2019/tests/test_hc_sr04/test_hc_sr04.ino

/*
 * Simple code to test the distance sensor function and electrical connections.
*/
int DIST_ECHO_PIN = 10;
int DIST_TRIG_PIN = 11;
long duration, cm;
 
void setup() {
  // Starts the serial com with PC
  Serial.begin(9600);
  Serial.println("Running setup function");

  //Defines inputs and outputs
  pinMode(DIST_TRIG_PIN, OUTPUT);
  pinMode(DIST_ECHO_PIN, INPUT);
}
 
void loop() {
  // The sensor is triggered by a HIGH pulse of 10 or more microseconds.
  // Gives a short LOW pulse beforehand to ensure a clean HIGH pulse:
  digitalWrite(DIST_TRIG_PIN, LOW);
  delayMicroseconds(5);
  digitalWrite(DIST_TRIG_PIN, HIGH);
  delayMicroseconds(10);
  digitalWrite(DIST_TRIG_PIN, LOW);
 
  // Reads the signal from the sensor: a HIGH pulse whose
  // duration is the time (in microseconds) from the sending
  // of the ping to the reception of its echo off of an object.
  //pinMode(DIST_ECHO_PIN, INPUT);
  duration = pulseIn(DIST_ECHO_PIN, HIGH);
 
  // Converts the time into a distance
  cm = (duration/2) / 29.1;
  
  Serial.print(cm);
  Serial.print("cm");
  Serial.println();

  delay(1000);
}