Dominik Święch
/
HCSR04v2
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Fork of
HCSR04
by 
Dominik Święch
Revision 1:0b3bdb910fe7, committed 2016-06-21
- Comitter:
- yruiewyrui3
- Date:
- Tue Jun 21 07:45:27 2016 +0000
- Parent:
- 0:86b2086be101
- Child:
- 2:8c633a86ddb5
- Commit message:
- .
Changed in this revision
| hcsr04.cpp | Show annotated file Show diff for this revision Revisions of this file |
--- a/hcsr04.cpp Mon Apr 14 08:23:09 2014 +0000
+++ b/hcsr04.cpp Tue Jun 21 07:45:27 2016 +0000
@@ -3,7 +3,7 @@
/*
*HCSR04.cpp
*/
-HCSR04::HCSR04(PinName t, PinName e) : trig(t), echo(e) {}
+HCSR04::HCSR04(PinName t, PinName e, long to) : trig(t), echo(e), time_out(to){}
long HCSR04::echo_duration() {
timer.reset(); //reset timer
@@ -12,18 +12,25 @@
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();
+ while(!echo); // start pulseIN
+ timer.start();
+ while(echo)
+ {
+ if(timer.read_us()>time_out)
+ break;
+ }
+ timer.stop();
+ long czas=timer.read_us();
+ if(czas<300)
+ return 0;
+ return timer.read_us();
}
//return distance in cm
long HCSR04::distance(){
duration = echo_duration();
- distance_cm = (duration/2)/29.1 ;
+ distance_cm = (duration/2.00)/29.10 ;
return distance_cm;
}
\ No newline at end of file