(DA) Internet of Things and Smart Electronics- ELE3006M2122 / Mbed OS 18689004Coursework

Coursework

hcsr04.cpp@45:f1db729741f7, 2022-02-04 (annotated)

Committer:
sesa514652
Date:
Fri Feb 04 16:44:14 2022 +0000
Revision:
45:f1db729741f7
Parent:
0:1f799c7cce2b 
Submission

Who changed what in which revision?

UserRevisionLine numberNew contents of line
sesa514652 0:1f799c7cce2b 1 #include "hcsr04.h"
sesa514652 0:1f799c7cce2b 2 #include "mbed.h"
sesa514652 0:1f799c7cce2b 3 /*
sesa514652 0:1f799c7cce2b 4 *HCSR04.cpp
sesa514652 0:1f799c7cce2b 5 */
sesa514652 0:1f799c7cce2b 6 HCSR04::HCSR04(PinName t, PinName e) : trig(t), echo(e) {}
sesa514652 0:1f799c7cce2b 7 long HCSR04::echo_duration() {
sesa514652 0:1f799c7cce2b 8
sesa514652 0:1f799c7cce2b 9 timer.reset(); //reset timer
sesa514652 0:1f799c7cce2b 10 trig=0; // trigger low
sesa514652 0:1f799c7cce2b 11 wait_us(2); // wait
sesa514652 0:1f799c7cce2b 12 trig=1; // trigger high
sesa514652 0:1f799c7cce2b 13 wait_us(10);
sesa514652 0:1f799c7cce2b 14 trig=0; // trigger low
sesa514652 0:1f799c7cce2b 15 while(!echo); // start pulseIN
sesa514652 0:1f799c7cce2b 16 timer.start();
sesa514652 0:1f799c7cce2b 17 while(echo);
sesa514652 0:1f799c7cce2b 18 timer.stop();
sesa514652 0:1f799c7cce2b 19 return timer.read_us();
sesa514652 0:1f799c7cce2b 20
sesa514652 0:1f799c7cce2b 21 }
sesa514652 0:1f799c7cce2b 22
sesa514652 0:1f799c7cce2b 23 //return distance in cm
sesa514652 0:1f799c7cce2b 24 long HCSR04::distance(){
sesa514652 0:1f799c7cce2b 25 duration = echo_duration();
sesa514652 0:1f799c7cce2b 26 distance_cm = (duration/2)/29.1 ;
sesa514652 0:1f799c7cce2b 27 return distance_cm;
sesa514652 0:1f799c7cce2b 28
sesa514652 0:1f799c7cce2b 29 }