CODEWITHSUNDEEP
arduinodistancesensors
Artūras Maziliauskas
Artūras Maziliauskas

Reputation: 101

HC-SR04 sensor acting crazy

I'm quite new to Arduino but I'm trying to learn but currently, I'm having an issue. The output when the sensor stationary shows distance spikes. Is it a faulty sensor or is there a problem in the code?

Output:

Distance: 3540.65
Distance: 25.93
Distance: 3528.96
Distance: 25.42
Distance: 3550.34
Distance: 25.88
Distance: 3536.78
Distance: 36.27
Distance: 3501.94
Distance: 25.42
Distance: 28.37
Distance: 3531.37
Distance: 24.51
Distance: 26.99

Code:

  * HC-SR04 example sketch
  *
  * https://create.arduino.cc/projecthub/Isaac100/getting-started-with-the- hc-sr04-ultrasonic-sensor-036380
  *
  * by Isaac100
  */

const int trigPin = 9;
const int echoPin = 10;

float duration, distance;

void setup() {
 pinMode(trigPin, OUTPUT);
 pinMode(echoPin, INPUT);
 Serial.begin(9600);
}

void loop() {
 digitalWrite(trigPin, LOW);
 delayMicroseconds(2);
 digitalWrite(trigPin, HIGH);
 delayMicroseconds(10);
 digitalWrite(trigPin, LOW);

 duration = pulseIn(echoPin, HIGH);
 distance = (duration*.0343)/2;
 Serial.print("Distance: ");
 Serial.println(distance);
 delay(100);
}

Upvotes: 1

Views: 885

Answers (1)

Kamil Słotwiński
Kamil Słotwiński

Reputation: 69

I think that you found answer to your question, but in future I would recommend you to filter those values. Maybe think about simple median filter or low pass filter. Median filter: Take last X(may be 5 for example) values and put them into an array. Sort the array. Get the array[(X/2)] value. Now its a bit more usefull. You may dynamically add data so you dont have to accumulate 10 of them and then filter it. For example if you receive new measurement A:
A - new measurement value
X - amount of data to accumulate (filter strength)
0 <= i < X
array[X] - array with accumulated data

array[i] = A;
i++;
if(i==X) i=0;

Simple as that.

Upvotes: 1

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