Revision 1:01ecd819e4ee, committed 2016-07-07

Comitter:

yruiewyrui3

Date:

Thu Jul 07 12:54:59 2016 +0000

Parent:

0:0bda99bb39a4

Commit message:

.

Changed in this revision

diff -r 0bda99bb39a4 -r 01ecd819e4ee HCSR04.cpp
--- a/HCSR04.cpp	Tue Oct 18 14:32:12 2011 +0000
+++ b/HCSR04.cpp	Thu Jul 07 12:54:59 2016 +0000
@@ -1,41 +1,37 @@
 #include "HCSR04.h"
 #include "mbed.h"
-
-
-HCSR04::HCSR04(PinName t, PinName e) : trig(t), echo(e) {}
-
-//      Trigger          Echo
-//      _______           _____________,,,,,,,,,
-// ____|  10us |_________| 150us-25ms, or 38ms if no obstacle
-// 
-
-//return echo duration in us (refer to digram above)
-long HCSR04::echo_duration() {
-    timer.reset();
-    trig = 0;
-    wait_us(2);
-    trig = 1;
+/*
+*HCSR04.cpp
+*/
+HCSR04::HCSR04(PinName t, PinName e, long to) : trig(t), echo(e), time_out(to){}
+ 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;
-    while(echo == 0);
+    trig=0;  // trigger low
+    while(!echo); // start pulseIN
     timer.start();
-    while(echo == 1);
+    while(echo)
+    {
+        if(timer.read_us()>time_out)        
+            break;
+    }
     timer.stop();
-    return timer.read_us();
+    
+    long czas=timer.read_us();
+    if(czas<300)
+        return 0;
+    return timer.read_us(); 
+ 
 }
-
-//return distance to nearest obstacle or returns -1 
-//if no obstacle within range
-//set sys to cm or inch accordingly
-long HCSR04::distance(int sys){
+ 
+//return distance in cm 
+    long HCSR04::distance(){
     duration = echo_duration();
-    if(duration > 30000)
-        return -1;
-    distacne_cm = duration /29 / 2 ;
-    distance_inc = duration / 74 / 2;
-    if (sys)
-        return distacne_cm;
-    else
-        return distance_inc;
-}
+    distance_cm = (duration*34)/1000/2 ;
+    return distance_cm;
 
+}
\ No newline at end of file

diff -r 0bda99bb39a4 -r 01ecd819e4ee HCSR04.h
--- a/HCSR04.h	Tue Oct 18 14:32:12 2011 +0000
+++ b/HCSR04.h	Thu Jul 07 12:54:59 2016 +0000
@@ -1,39 +1,49 @@
-//Library for controlling ultrasonic module HCSR04
-//Ported by hiawoood from arduino library orgininally created by ITead studio.
-//Instantiate object by supplying the proper pin numbers of "trigger" and "echo"
-//e.g. 
-/*
-        int main() {
-            Ultrasonic sensor(p5, p6);
-            while(1){
-                long distance = sensor.distance(CM);
-                printf("Distance:%d\n");
-                wait(0.1);
-            }
-        }
+/* File: HCSR04.h
+ * Author: Antonio Buonanno  
+ *Board: STM NUCLEO F401RE, 
+ *Hardware: Ultrasonic Range HC-SR04,  
+ * 
+ *This work derived from Arduino library, 
+ *
+ * Desc: driver for HCSR04 Ultrasonic Range Finder.  The returned range
+ *       is in units of meters.
+ *  
+ *       
+ *
 */
 
-
+/* EXAMPLE
+#include "mbed.h"
+#include "hcsr04.h"
 
-#ifndef HCSR04_H
-#define HCSR04_H
-
+//D12 TRIGGER D11 ECHO
+   HCSR04 sensor(D12, D11); 
+int main() {
+    while(1) {
+        
+     long distance = sensor.distance();   
+      printf("distanza  %d  \n",distance);
+      wait(1.0); // 1 sec  
+        
+    }
+}
+*/
+#ifndef hcsr04_H
+#define hcsr04_H
 #include "mbed.h"
 
-#define CM 1
-#define INC 0
 
 class HCSR04 {
   public:
-    HCSR04(PinName t, PinName e);
+    HCSR04(PinName t, PinName e, long to);
     long echo_duration();
-    long distance(int sys);
-
+    long distance();
+ 
     private:
         DigitalOut trig;
         DigitalIn echo;
         Timer timer;
-        long duration,distacne_cm,distance_inc;
+        long duration,distance_cm,time_out;
 };
-
+ 
 #endif
\ No newline at end of file