Supakorn Meelarp
/
8B_Bike_Light_Back
Bike Light Back Side
hcsr04.cpp@0:b5bafad435c8, 2015-12-09 (annotated)
- Committer:
- kornvarrel
- Date:
- Wed Dec 09 10:15:06 2015 +0000
- Revision:
- 0:b5bafad435c8
Bike Light Back Side
Who changed what in which revision?
User | Revision | Line number | New contents of line |
---|---|---|---|
kornvarrel | 0:b5bafad435c8 | 1 | #include "hcsr04.h" |
kornvarrel | 0:b5bafad435c8 | 2 | #include "mbed.h" |
kornvarrel | 0:b5bafad435c8 | 3 | /* |
kornvarrel | 0:b5bafad435c8 | 4 | *HCSR04.cpp |
kornvarrel | 0:b5bafad435c8 | 5 | */ |
kornvarrel | 0:b5bafad435c8 | 6 | HCSR04::HCSR04(PinName t, PinName e) : trig(t), echo(e) {} |
kornvarrel | 0:b5bafad435c8 | 7 | long HCSR04::echo_duration() { |
kornvarrel | 0:b5bafad435c8 | 8 | |
kornvarrel | 0:b5bafad435c8 | 9 | timer.reset(); //reset timer |
kornvarrel | 0:b5bafad435c8 | 10 | trig=0; // trigger low |
kornvarrel | 0:b5bafad435c8 | 11 | wait_us(2); // wait |
kornvarrel | 0:b5bafad435c8 | 12 | trig=1; // trigger high |
kornvarrel | 0:b5bafad435c8 | 13 | wait_us(10); |
kornvarrel | 0:b5bafad435c8 | 14 | trig=0; // trigger low |
kornvarrel | 0:b5bafad435c8 | 15 | while(!echo); // start pulseIN |
kornvarrel | 0:b5bafad435c8 | 16 | timer.start(); |
kornvarrel | 0:b5bafad435c8 | 17 | while(echo); |
kornvarrel | 0:b5bafad435c8 | 18 | timer.stop(); |
kornvarrel | 0:b5bafad435c8 | 19 | return timer.read_us(); |
kornvarrel | 0:b5bafad435c8 | 20 | |
kornvarrel | 0:b5bafad435c8 | 21 | } |
kornvarrel | 0:b5bafad435c8 | 22 | |
kornvarrel | 0:b5bafad435c8 | 23 | //return distance in cm |
kornvarrel | 0:b5bafad435c8 | 24 | long HCSR04::distance(){ |
kornvarrel | 0:b5bafad435c8 | 25 | duration = echo_duration(); |
kornvarrel | 0:b5bafad435c8 | 26 | distance_cm = (duration/2)/29.1 ; |
kornvarrel | 0:b5bafad435c8 | 27 | return distance_cm; |
kornvarrel | 0:b5bafad435c8 | 28 | |
kornvarrel | 0:b5bafad435c8 | 29 | } |