Ultrasonic Rangefinder (SRF05) Expected Results?

Forum 2005-2010 (read only) Hardware Interfacing
10

Gah tried that, and I get even more erratic results! Hehe, I'm not sure what's going on here at all. I'll check this method on my other Arduino and the other SRF05 unit later on, for now here's the (new) complete code, after halving the ultrasound duration before dividing by 58.

int ultraSoundpin = 6;
char disp_string[80];
unsigned int ultrasoundDuration = 0;
unsigned int ultra_dist = 0;

void setup() {
  Serial.begin(9600);
}

void loop() {

  // switch pin to output
  pinMode(ultraSoundpin, OUTPUT);

  // send a low, wait 2 microseconds, send a high then wait 10 microseconds
  digitalWrite(ultraSoundpin, LOW);
  delayMicroseconds(2);
  digitalWrite(ultraSoundpin, HIGH);
  delayMicroseconds(10);
  digitalWrite(ultraSoundpin, LOW);

   // switch pin to input
  pinMode(ultraSoundpin, INPUT);

  // wait for a pulse to come in as high
  ultrasoundDuration = pulseIn(ultraSoundpin, HIGH);
  ultra_dist = (ultrasoundDuration/2);
  // output
  Serial.print(ultra_dist/58, DEC);
  Serial.print(" cm");
  //Serial.print(dist);
  //Serial.print(" cm");
  Serial.println();
  delay(2000);
}

I've tried this with unsigned ints and longs, and with a long for the duration and an int for the distance... just gives me random results from 7-500 odd....!

Thom