78 lines
1.6 KiB
C
78 lines
1.6 KiB
C
/*
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* 超声波距离传感器
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*
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*/
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#include <wiringPi.h>
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#include <sys/time.h>
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#include <stdlib.h>
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#include <stdio.h>
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#include <string.h>
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int is_num(int n, char *argv[])
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{
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int j = 0;
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int i;
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char parameter[10];
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strcpy(parameter, argv[n]);
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int len = strlen(parameter);
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for (i = 0; i < len; i++) {
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if (parameter[i] <= 57 && parameter[i] >= 48) //0~9的ASCII码是48~57
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{
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j++;
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}
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}
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if (j == len) {
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return 1;
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} else {
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return 0;
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}
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}
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int main(int argc, char *argv[])
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{
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if (argc != 3) {
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printf("Parameter error.\n");
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exit(1);
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}
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if (is_num(1, argv) == 0) {
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printf("Parameter error, Parameter 1 is the tring pin\n");
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exit(1);
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}
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if (is_num(2, argv) == 0) {
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printf("Parameter error, Parameter 2 is the echo pin\n");
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exit(1);
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}
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int pin_tring = atol(argv[1]);
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int pin_echo = atol(argv[2]);
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struct timeval tv1;
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struct timeval tv2;
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long start_time, stop_time;
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float distance;
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if (wiringPiSetup() == -1) {
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exit(0);
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return 0;
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}
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digitalWrite(pin_tring, LOW);
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digitalWrite(pin_tring, HIGH);
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delayMicroseconds(10);
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digitalWrite(pin_tring, LOW);
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while (!(digitalRead(pin_echo) == 1)) ;
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gettimeofday(&tv1, NULL);
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while (!(digitalRead(pin_echo) == 0)) ;
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gettimeofday(&tv2, NULL);
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start_time = tv1.tv_sec * 1000000 + tv1.tv_usec;
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stop_time = tv2.tv_sec * 1000000 + tv2.tv_usec;
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distance = (float)(stop_time - start_time) / 1000000 * 34000 / 2;
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printf("%0.0f\n", distance);
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return distance;
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}
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