Jose Ruiz / HCSR042

Librería HCSR04 con algunas modificaciones

Dependents:   ZMOTO42

HCSR042.cpp@0:70e05cce830a, 2014-12-04 (annotated)

Committer:
jaruiz
Date:
Thu Dec 04 06:27:21 2014 +0000
Revision:
0:70e05cce830a
Libreria HCSR04 con algunas modificaciones

Who changed what in which revision?

UserRevisionLine numberNew contents of line
jaruiz 0:70e05cce830a 1 #include "HCSR042.h"
jaruiz 0:70e05cce830a 2 #include "mbed.h"
jaruiz 0:70e05cce830a 3
jaruiz 0:70e05cce830a 4
jaruiz 0:70e05cce830a 5 HCSR042::HCSR042(PinName t, PinName e) : trig(t), echo(e) {}
jaruiz 0:70e05cce830a 6
jaruiz 0:70e05cce830a 7 // Trigger Echo
jaruiz 0:70e05cce830a 8 // _______ _____________,,,,,,,,,
jaruiz 0:70e05cce830a 9 // ____| 10us |_________| 150us-25ms, or 38ms if no obstacle
jaruiz 0:70e05cce830a 10 //
jaruiz 0:70e05cce830a 11
jaruiz 0:70e05cce830a 12 //return echo duration in us (refer to digram above)
jaruiz 0:70e05cce830a 13 long HCSR042::echo_duration() {
jaruiz 0:70e05cce830a 14 timer.reset();
jaruiz 0:70e05cce830a 15 trig = 0;
jaruiz 0:70e05cce830a 16 wait_us(2);
jaruiz 0:70e05cce830a 17 trig = 1;
jaruiz 0:70e05cce830a 18 wait_us(10);
jaruiz 0:70e05cce830a 19 trig = 0;
jaruiz 0:70e05cce830a 20 while(echo == 0);
jaruiz 0:70e05cce830a 21 timer.start();
jaruiz 0:70e05cce830a 22 while(echo == 1);
jaruiz 0:70e05cce830a 23 timer.stop();
jaruiz 0:70e05cce830a 24 return timer.read_us();
jaruiz 0:70e05cce830a 25 }
jaruiz 0:70e05cce830a 26
jaruiz 0:70e05cce830a 27 //return distance to nearest obstacle or returns -1
jaruiz 0:70e05cce830a 28 //if no obstacle within range
jaruiz 0:70e05cce830a 29 //set sys to cm or inch accordingly
jaruiz 0:70e05cce830a 30 long HCSR042::distance(int sys){
jaruiz 0:70e05cce830a 31 duration = echo_duration();
jaruiz 0:70e05cce830a 32 if(duration > 30000)
jaruiz 0:70e05cce830a 33 return -1;
jaruiz 0:70e05cce830a 34 distacne_cm = duration /29 / 2 ;
jaruiz 0:70e05cce830a 35 distance_inc = duration / 74 / 2;
jaruiz 0:70e05cce830a 36 if (sys)
jaruiz 0:70e05cce830a 37 return distacne_cm;
jaruiz 0:70e05cce830a 38 else
jaruiz 0:70e05cce830a 39 return distance_inc;
jaruiz 0:70e05cce830a 40 }
jaruiz 0:70e05cce830a 41