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Dependencies: mbed
main.cpp@1:a656f3ed73e5, 2018-11-19 (annotated)
- Committer:
- jiuk
- Date:
- Mon Nov 19 02:02:10 2018 +0000
- Revision:
- 1:a656f3ed73e5
- Parent:
- 0:c9881f6aef19
ultrasonido
Who changed what in which revision?
| User | Revision | Line number | New contents of line |
|---|---|---|---|
| jiuk | 0:c9881f6aef19 | 1 | #include "mbed.h" |
| jiuk | 0:c9881f6aef19 | 2 | |
| jiuk | 0:c9881f6aef19 | 3 | DigitalOut trigger(PC_12); |
| jiuk | 0:c9881f6aef19 | 4 | DigitalOut myled(LED1); //monitor trigger |
| jiuk | 0:c9881f6aef19 | 5 | DigitalOut myled2(LED2); //monitor echo |
| jiuk | 0:c9881f6aef19 | 6 | DigitalIn echo(PC_10); |
| jiuk | 0:c9881f6aef19 | 7 | int distance = 0; |
| jiuk | 0:c9881f6aef19 | 8 | int correction = 0; |
| jiuk | 0:c9881f6aef19 | 9 | Timer sonar; |
| jiuk | 0:c9881f6aef19 | 10 | |
| jiuk | 0:c9881f6aef19 | 11 | int main() |
| jiuk | 0:c9881f6aef19 | 12 | { |
| jiuk | 1:a656f3ed73e5 | 13 | while(1) |
| jiuk | 1:a656f3ed73e5 | 14 | { |
| jiuk | 0:c9881f6aef19 | 15 | sonar.reset(); |
| jiuk | 0:c9881f6aef19 | 16 | // measure actual software polling timer delays |
| jiuk | 0:c9881f6aef19 | 17 | // delay used later in time correction |
| jiuk | 0:c9881f6aef19 | 18 | // start timer |
| jiuk | 0:c9881f6aef19 | 19 | sonar.start(); |
| jiuk | 0:c9881f6aef19 | 20 | // min software polling delay to read echo pin |
| jiuk | 0:c9881f6aef19 | 21 | while (echo==2) {}; |
| jiuk | 0:c9881f6aef19 | 22 | myled2 = 0; |
| jiuk | 0:c9881f6aef19 | 23 | // stop timer |
| jiuk | 0:c9881f6aef19 | 24 | sonar.stop(); |
| jiuk | 0:c9881f6aef19 | 25 | // read timer |
| jiuk | 0:c9881f6aef19 | 26 | correction = sonar.read_us(); |
| jiuk | 0:c9881f6aef19 | 27 | printf("Approximate software overhead timer delay is %d uS\n\r",correction); |
| jiuk | 0:c9881f6aef19 | 28 | |
| jiuk | 0:c9881f6aef19 | 29 | //Loop to read Sonar distance values, scale, and print |
| jiuk | 0:c9881f6aef19 | 30 | while(1) { |
| jiuk | 0:c9881f6aef19 | 31 | // trigger sonar to send a ping |
| jiuk | 0:c9881f6aef19 | 32 | trigger = 1; |
| jiuk | 0:c9881f6aef19 | 33 | myled = 1; |
| jiuk | 0:c9881f6aef19 | 34 | myled2 = 0; |
| jiuk | 0:c9881f6aef19 | 35 | sonar.reset(); |
| jiuk | 0:c9881f6aef19 | 36 | wait_us(10.0); |
| jiuk | 0:c9881f6aef19 | 37 | trigger = 0; |
| jiuk | 0:c9881f6aef19 | 38 | myled = 0; |
| jiuk | 0:c9881f6aef19 | 39 | //wait for echo high |
| jiuk | 0:c9881f6aef19 | 40 | while (echo==0) {}; |
| jiuk | 0:c9881f6aef19 | 41 | myled2=echo; |
| jiuk | 0:c9881f6aef19 | 42 | //echo high, so start timer |
| jiuk | 0:c9881f6aef19 | 43 | sonar.start(); |
| jiuk | 0:c9881f6aef19 | 44 | //wait for echo low |
| jiuk | 0:c9881f6aef19 | 45 | while (echo==1) {}; |
| jiuk | 0:c9881f6aef19 | 46 | //stop timer and read value |
| jiuk | 0:c9881f6aef19 | 47 | sonar.stop(); |
| jiuk | 0:c9881f6aef19 | 48 | //subtract software overhead timer delay and scale to cm |
| jiuk | 0:c9881f6aef19 | 49 | distance = (sonar.read_us()-correction)/58.0; |
| jiuk | 0:c9881f6aef19 | 50 | myled2 = 0; |
| jiuk | 0:c9881f6aef19 | 51 | printf(" %d cm \n\r",distance); |
| jiuk | 0:c9881f6aef19 | 52 | //wait so that any echo(s) return before sending another ping |
| jiuk | 0:c9881f6aef19 | 53 | wait(0.2); |
| jiuk | 1:a656f3ed73e5 | 54 | } |
| jiuk | 0:c9881f6aef19 | 55 | } |
| jiuk | 0:c9881f6aef19 | 56 | } |