RYU HOSEONG / HCSR04

create

Dependents:   Nucleo_UltrasonicHelloWorld

Fork of HCSR04 by Antoniolinux B.

hcsr04.cpp

Committer:
ryuhs74
Date:
2015-08-10
Revision:
1:a6912eacfb20
Parent:
0:86b2086be101

File content as of revision 1:a6912eacfb20:

#include "hcsr04.h"
#include "mbed.h"
/*
*HCSR04.cpp
*/
HCSR04::HCSR04(PinName t, PinName e) : trig(t), echo(e) {}

long HCSR04::echo_duration() {        
    timer.reset();  //reset timer
    trig=0;   // trigger low 
    wait_us(2); //  wait 
    trig=1;   //  trigger high
    wait_us(10);
    trig=0;  // trigger low
    
    while(!echo); // start pulseIN
        timer.start();
    
    while(echo);
        timer.stop();
    return timer.read_us(); 
}

//return distance in cm 
long HCSR04::distance(){
    duration = echo_duration();
    distance_cm = (duration/2)/29.1  ;
    return distance_cm;
}