Re: 3 Pin ultrasonic sensor in galileo

I tried again the answer of DinoT_Intel and still giving me 0. Maybe is the sensor the problem. Maybe the ultrasonic sensor of seeedstudio doesn't work with that code, i don 't know.

My 4 pin sensor is a HC-SR04 and this is the code that i use is this. I don't remember where I get it but it works.

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#include <TimerOne.h>

#define speakerPin 9

#define trigPin 3

#define echoPin2 2

unsigned long SEC=1000; //1sec = 10^6microsecond

long  pstart=0;

long  pstop=0;

boolean got=false;

int freq=500; //in Hz (1/sec)

int tt=SEC/freq/2;

void setup() {

  Serial.begin (9600);

  pinMode(trigPin, OUTPUT_FAST);

  pinMode(echoPin2, INPUT_FAST);

  Timer1.initialize(SEC);

  //you need at least 15us + ping time. it didnt work below 1000us for me for below code

}

void pingUltra()

{

  fastDigitalWrite(trigPin, LOW);

  delayMicroseconds(2);

  fastDigitalWrite(trigPin, HIGH);

  delayMicroseconds(10);

  fastDigitalWrite(trigPin, LOW);// NOT checking for LOW. it seemed to hang here if i used it.

  pstart=micros();

  while(digitalRead(echoPin2)==HIGH ){}

  pstop=micros();

}

double media(int x)

{

  double med=0;

  for(int i=0; i<x;i++)

  {

    pingUltra();

    med+=((pstop-pstart)/57)+4;

  }

  return med/x;

}

void loop()

{ 

  double dist=media(10);

  if(dist!=0)

  {

      Serial.print("CM: ");

      Serial.println(dist);

      for(int i=0;i<10;i++)

     {

          analogWrite(speakerPin,200);

          delayMicroseconds(tt);

          analogWrite(speakerPin,0);

          delayMicroseconds(tt);

     }

        analogWrite(speakerPin,00);

  }

  delay(1000);

}

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