Problem in the reading of an ultrasonic sensor

Projects General Guidance
1

So, I am tying to figure out how to work with an HC-SR04 ultrasonic sensor so I tryed this easy code:

const int trig = 6;
const int echo = 5;

long totaltime;
int distance;

void setup ()
{
  pinMode(trig, OUTPUT);
  pinMode(echo, INPUT);
  Serial.begin(9600);

}

void loop()
{
  digitalWrite(trig, LOW);
  delayMicroseconds(2);

  digitalWrite(trig, HIGH);
  delayMicroseconds (20);
  digitalWrite(trig, LOW);

  totaltime = pulseIn(echo, HIGH);

  distance= totaltime*0.034/2;

  Serial.print("Distance:");
  Serial.println(distance);
}

But inbetween every read it does it reads a zero, so he is constandly turning off and i can't see the mistake I'm making, so has anyone an idea how to solve this?

2

The maximum sample rate of this sensor is 40Hz. So the Arduino needs to wait 25ms between readings. Your code doesn't wait.

3

Study the documentation on pulseln() and you will find the answer!