Library used to implement HCSR04 Ranging Module.
Dependents: 2Project3_Robot2_Final
Fork of HCSR04 by
HCSR04.cpp@1:348fdd74f030, 2016-05-02 (annotated)
- Committer:
- Jakschwa
- Date:
- Mon May 02 17:22:54 2016 +0000
- Revision:
- 1:348fdd74f030
- Parent:
- 0:0bda99bb39a4
This library was used to implement the HCSR04 ranging module used to sense distances in our Multi-Robot Security System Project in IUPUI's ECE 59500 Embedded Systems Design course.
Who changed what in which revision?
User | Revision | Line number | New contents of line |
---|---|---|---|
aralshukaili | 0:0bda99bb39a4 | 1 | #include "HCSR04.h" |
aralshukaili | 0:0bda99bb39a4 | 2 | #include "mbed.h" |
aralshukaili | 0:0bda99bb39a4 | 3 | |
aralshukaili | 0:0bda99bb39a4 | 4 | |
aralshukaili | 0:0bda99bb39a4 | 5 | HCSR04::HCSR04(PinName t, PinName e) : trig(t), echo(e) {} |
aralshukaili | 0:0bda99bb39a4 | 6 | |
aralshukaili | 0:0bda99bb39a4 | 7 | // Trigger Echo |
aralshukaili | 0:0bda99bb39a4 | 8 | // _______ _____________,,,,,,,,, |
aralshukaili | 0:0bda99bb39a4 | 9 | // ____| 10us |_________| 150us-25ms, or 38ms if no obstacle |
aralshukaili | 0:0bda99bb39a4 | 10 | // |
aralshukaili | 0:0bda99bb39a4 | 11 | |
aralshukaili | 0:0bda99bb39a4 | 12 | //return echo duration in us (refer to digram above) |
aralshukaili | 0:0bda99bb39a4 | 13 | long HCSR04::echo_duration() { |
aralshukaili | 0:0bda99bb39a4 | 14 | timer.reset(); |
aralshukaili | 0:0bda99bb39a4 | 15 | trig = 0; |
aralshukaili | 0:0bda99bb39a4 | 16 | wait_us(2); |
aralshukaili | 0:0bda99bb39a4 | 17 | trig = 1; |
aralshukaili | 0:0bda99bb39a4 | 18 | wait_us(10); |
aralshukaili | 0:0bda99bb39a4 | 19 | trig = 0; |
aralshukaili | 0:0bda99bb39a4 | 20 | while(echo == 0); |
aralshukaili | 0:0bda99bb39a4 | 21 | timer.start(); |
aralshukaili | 0:0bda99bb39a4 | 22 | while(echo == 1); |
aralshukaili | 0:0bda99bb39a4 | 23 | timer.stop(); |
aralshukaili | 0:0bda99bb39a4 | 24 | return timer.read_us(); |
aralshukaili | 0:0bda99bb39a4 | 25 | } |
aralshukaili | 0:0bda99bb39a4 | 26 | |
aralshukaili | 0:0bda99bb39a4 | 27 | //return distance to nearest obstacle or returns -1 |
aralshukaili | 0:0bda99bb39a4 | 28 | //if no obstacle within range |
aralshukaili | 0:0bda99bb39a4 | 29 | //set sys to cm or inch accordingly |
Jakschwa | 1:348fdd74f030 | 30 | long HCSR04::distance(void){ |
aralshukaili | 0:0bda99bb39a4 | 31 | duration = echo_duration(); |
aralshukaili | 0:0bda99bb39a4 | 32 | if(duration > 30000) |
Jakschwa | 1:348fdd74f030 | 33 | return 1000; |
aralshukaili | 0:0bda99bb39a4 | 34 | distacne_cm = duration /29 / 2 ; |
aralshukaili | 0:0bda99bb39a4 | 35 | distance_inc = duration / 74 / 2; |
Jakschwa | 1:348fdd74f030 | 36 | return distacne_cm; |
aralshukaili | 0:0bda99bb39a4 | 37 | } |
aralshukaili | 0:0bda99bb39a4 | 38 |