HC-SR04 sensor stops working and reads 0

Projects Programming
1

hello,

I am having a problem with this sensor, i have tried several different versions of this code and it still does the same thing, i was reading another thread and basically the sensor does not have a time out feature on it and if it does not read the ping it will hang on a value (0), i am unsure on how to implement a timeout on it. i have tried different methods but i cant get them to work.

any help would be greatly appreciated thanks.

here is the code

#define echoPin 7 // Echo Pin
#define trigPin 8 // Trigger Pin
#define LEDPin 13 // Onboard LED

int maximumRange = 200; // Maximum range needed
int minimumRange = 0; // Minimum range needed
long duration, distance; // Duration used to calculate distance

void setup() {
 Serial.begin (9600);
 pinMode(trigPin, OUTPUT);
 pinMode(echoPin, INPUT);
 pinMode(LEDPin, OUTPUT); // Use LED indicator (if required)
}

void loop() {
/* The following trigPin/echoPin cycle is used to determine the
 distance of the nearest object by bouncing soundwaves off of it. */ 
 digitalWrite(trigPin, LOW); 
 delayMicroseconds(2); 

 digitalWrite(trigPin, HIGH);
 delayMicroseconds(10); 
 
 digitalWrite(trigPin, LOW);
 duration = pulseIn(echoPin, HIGH);
 

 
 //Calculate the distance (in cm) based on the speed of sound.
 distance = duration/58.2;
  if (distance == -1)
    digitalWrite(echoPin, HIGH);
 delayMicroseconds(10); 
 
 digitalWrite(echoPin, LOW);
 if (distance >= maximumRange || distance <= minimumRange){
 /* Send a negative number to computer and Turn LED ON 
 to indicate "out of range" */
 Serial.println("-1");
 digitalWrite(LEDPin, HIGH); 
 }
 else {
 /* Send the distance to the computer using Serial protocol, and
 turn LED OFF to indicate successful reading. */
 Serial.println(distance);
 digitalWrite(LEDPin, LOW); 
 }
 
 //Delay 50ms before next reading.
 delay(50);
}
2

PulseIn() takes a third parameter, timeout. So pulseIn(echoPin, HIGH, 30000); will timeout after 30 milliseconds

3

i just tried that out and it still gets stuck on 0. dont suppose you have any ideas?
thanks

4

After setting your echo pin to input, do nothing else with it apart from pass it to pulsein. You are using it with digitalWrite.

5

pYro_65:
After setting your echo pin to input, do nothing else with it apart from pass it to pulsein. You are using it with digitalWrite.

i have removed all of that, I still cant get it to work. It still gets stuck on 0 when it does not receive a ping

6

If there is nothing reflecting the ultrasound, then the result is 0.

You logic needs to interpret 0 as "too far away", and not as "very close".

7

michinyon:
If there is nothing reflecting the ultrasound, then the result is 0.

You logic needs to interpret 0 as "too far away", and not as "very close".

no it works for a bit but if i doesn't receive a ping it goes to zero and stays there i have to tap on it to get it working again

8

ryisnelly10:
no it works for a bit but if i doesn't receive a ping it goes to zero and stays there i have to tap on it to get it working again.

i have just received several hc-sr04 with same bug. when it comes to out of range it returns 0 and set 1 on echo. senseor powered from 5V from arduino and GND to arduino's GND. thist code helps for me. it resets the sensor.
if (duration == 0) {
pinMode(echoPin,OUTPUT);
digitalWrite(echoPin,LOW);
delay(1);
pinMode(echoPin,INPUT);
}

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