Ultrasonic sensor not giving correct readings

Using Arduino Sensors
1

Hey guys!

I have been working with ultrasonic sensors for a while but never encountered anything like this but, now a days am facing one problem ,my ultrasonic sensor is not giving me correct readings just showing '0' as distance even when am trying a simple code.

Help please....

// defines pins numbers
const int trigPin = 9;
const int echoPin = 10;
const int buzzer = 11;
const int ledPin = 13;

// defines variables
long duration;
int distance;
int safetyDistance;

void setup() {
pinMode(trigPin, OUTPUT); // Sets the trigPin as an Output
pinMode(echoPin, INPUT); // Sets the echoPin as an Input
pinMode(buzzer, OUTPUT);
pinMode(ledPin, OUTPUT);
Serial.begin(9600); // Starts the serial communication
}

void loop() {
// Clears the trigPin
digitalWrite(trigPin, LOW);
delayMicroseconds(2);

// Sets the trigPin on HIGH state for 10 micro seconds
digitalWrite(trigPin, HIGH);
delayMicroseconds(10);
digitalWrite(trigPin, LOW);

// Reads the echoPin, returns the sound wave travel time in microseconds
duration = pulseIn(echoPin, HIGH);

// Calculating the distance
distance= duration*0.034/2;

safetyDistance = distance;
if (safetyDistance <= 5){
** digitalWrite(buzzer, HIGH);**
** digitalWrite(ledPin, HIGH);**
}
else{
** digitalWrite(buzzer, LOW);**
** digitalWrite(ledPin, LOW);**
}

// Prints the distance on the Serial Monitor
Serial.print("Distance: ");
Serial.println(distance);
}

2

Have you tried debugging by printing the value returned by : duration = pulseIn(echoPin, HIGH);?

That is the first place to begin.

Also look at some of your computations that use floating point to compute an integer.

Paul

3

Hi,

You should try this code out, it worked for me:

// defines arduino pins numbers
const int trigPin = 12;
const int echoPin = 11;
// defines variables
long duration;
int distance;
void setup() 
{
pinMode(trigPin, OUTPUT); // Sets the trigPin as an Output
pinMode(echoPin, INPUT); // Sets the echoPin as an Input
Serial.begin(9600); // Starts the serial communication
}
void loop() {
// Clears the trigPin
digitalWrite(trigPin, LOW);
delayMicroseconds(2);
// Sets the trigPin on HIGH state for 10 micro seconds
digitalWrite(trigPin, HIGH);
delayMicroseconds(10);
digitalWrite(trigPin, LOW);
// Reads the echoPin, returns the sound wave travel time in microseconds
duration = pulseIn(echoPin, HIGH);
// Calculating the distance
distance= duration*0.034/2;
// Prints the distance on the Serial Monitor
Serial.print("Distance from the object = ");
Serial.print(distance);
Serial.println(" cm");
delay(1000);
}

Connect Pins as follows:

  • Pin # 11 of Arduino is connected with Echo Pin of Ultrasonic Sensor HC-SR04.
  • Pin # 12 of Arduino is connected with Trig Pin of Ultrasonic Sensor.

Upload code and open your Serial Terminal, data will appear.

Thanks.