[SOLVED] HC-SR4 Ultrasonic reading 357's

Other Hardware Sensors
1

It is reading this max value unless I put my flat hand at nearly exactly a 90deg tangent as if it were a laser. It is intended to detect the presence of someone directly in front of door as if entering (not as if visiting). Heads don't seem to provide enough reflectance. I had it make tones based on distance measured. I'm unsure if my sensor is just not the correct type for job, or it's defective.

**** Solved: Used library NewPing.h in lieu of ultrasonic.h. Much better response.

2

Hi,

I have worked on HC-SR04 Ultrasonic Sensor and it works really great. You can easily convert the distance from hurdle into cm and inches.

I think you must be doing something wrong in the coding. Share your code and I will check it out.

Thanks.

3

Well, there I think i'm fine because there isn't much to code. This function is called once per second. If somehow I couldn't divide by 2.54 to get inches, I'd still be happy. Problem is it's very insensitive. I got it from aliexpress.com (China) and one of two was a total dud... so maybe this one is bad too.

void distanceCheck() {
  int distance = ultrasonic.read();
  //distance = random(0,357);
    int beepTone = ((distance * 3) + 1000);
 noTone(HO8);
  tone(HO8, beepTone, 400);
  //Serial.print(distance); Serial.println("cm");
  if ((distance == 0) || (distance > 350)) return; //throw out invalid readings.
  distanceA[iG] = distance;
  iG++;
  if (iG == 8) {
    iG == 0;
  } //loop of iG (global)
  distance = distanceArrayMin();

  eventName = String(distance);
  long number = 7090000;
  number = number + distance;
  sp(number);
  if (distance < 210) {
    powerBoostInc++;
    if (powerBoostInc > 5)  {
      powerBoost(1);
      sp(7015001);
      powerBoostInc = 0;
      eventName = "Door open."; //Because Doorbell doesn't work (doesn't sound)
      beep(1, 1);
    }
  }
  if (distance > 240) {
    powerBoostInc++;
    if (powerBoostInc > 5) {
      powerBoost(-1);
      sp(7015000);
      powerBoostInc = 0;
    }
  }
}
4

Hi,

Try this code out:

// 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);
}

It's for Ultrasonic sensor HC-SR04. Connect Pins as follows:

  • Trigger Pin to Pin # 12 of Arduino.
  • Echo Pin to Pin # 11 of Arduino.

After uploading the code, open your Serial Monitor and test out your software. For code source, check Ultrasonic Sensor Arduino Interfacing.

Thanks.

5

Thanks, in the time intervening, I found a NewPing library which when I gutted out parts of, worked much better.