Help with HC-SR04 Ultrasonic Range Finder

Other Hardware Sensors
1

I just received my HC-SR04 from Hong-Kong and I am having trouble getting it to work with my ATMega2560. The ATMega2560 is connected to my laptop via USB, and the HC-SR04 is using 5V and ground from the Arduino for power. I have the trigger connected to Pin 2 and the echo to pin 3. I have the Ultrasonic library downloaded from ITead and I changed their example a little bit because I don't have an LCD.

I have tried both of the following code, and in both cases I get nothing but "0 CM" being printed to the serial monitor.

double ping(int outPin, int inPin) //Get CM to obstacle in front of the sensor
{
  long duration;
  pinMode(outPin, OUTPUT);
  pinMode(inPin, INPUT);
  digitalWrite(outPin, LOW);
  delayMicroseconds(2);
  digitalWrite(outPin, HIGH);
  delayMicroseconds(10);
  digitalWrite(outPin, LOW);
  delayMicroseconds(10);
  duration = pulseIn(inPin, HIGH);
  return duration / 29.0 / 2.0;
}

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

void loop()			  
{
  Serial.print(ping(2, 3)); Serial.println("cm");
  delay(500);
}

#include "Ultrasonic.h"
Ultrasonic ultrasonic(2,3);

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

void loop()
{
  Serial.print(ultrasonic.Ranging(CM)); Serial.println("cm");
  delay(100);
}

I read that sometimes people have an issue with the HC-SR04 if you start it up with nothing out in front of it to echo. I tried with and without a barrier in front and both ways I still only get "0 CM" on the monitor.

Does anyone have any ideas on what I may be doing wrong? Also is there any way to test the HC-SR04 to know if it is defective?

Please let me know if I need to provide any additional info.

Thanks a lot.

2

no such sensor but try this

#include "Ultrasonic.h"

Ultrasonic ultrasonic(2,3);

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

void loop()
{
  float x = ultrasonic.Ranging(CM);
  Serial.print(x,4); 
  Serial.println("cm");
  delay(100);
}

What datatype does ultrasonic.Ranging(CM) return?

an the other app similar

double ping(int outPin, int inPin) //Get CM to obstacle in front of the sensor
{
  long duration;
  pinMode(outPin, OUTPUT);
  pinMode(inPin, INPUT);
  digitalWrite(outPin, LOW);
  delayMicroseconds(2);
  digitalWrite(outPin, HIGH);
  delayMicroseconds(10);
  digitalWrite(outPin, LOW);
  delayMicroseconds(10);
  duration = pulseIn(inPin, HIGH);
  return duration / 29.0 / 2.0;
}

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

void loop()			  
{
  float dist = ping(2,3);
  Serial.print(dist, 4);
  Serial.println("cm");
  delay(500);
}
3

I returned the first HC-SR04 and the ebay seller from Hong Kong sent me a second one to try. The new one works great and I can say that both versions of the code above will work with the HC-SR04.

4

The datasheet looks a bit confused to me.

On the face of it, it looks like a cheap knock-off of Devantech's device (It has a two pin interface with "trig" and "echo"), but the example code looks more like it is a cheap knock-off of the Ping sensor, with a single pin interface.

I don't have one, so I'm going to remain confused.

5

So I try it and this error shows:

.cpp:1:24: error: Ultrasonic.h: No such file or directory
:1: error: 'Ultrasonic' does not name a type
.cpp: In function 'void loop()':
:10: error: 'ultrasonic' was not declared in this scope
:10: error: 'CM' was not declared in this scope

no clue, can anyone help?