超声波测距的代码

连接5V和GND,超声波模块的Trig和Echo引脚可以连接至树莓派的任意GPIO引脚,连线方式和我们的不一样也没关系,记住Trig和Echo引脚对应的BCM引脚编码

C语言版

#include <wiringPi.h>  
#include <stdio.h>  
#include <sys/time.h>  
  
#define Trig    3 
#define Echo    4 
  
void ultraInit(void)  
{  
    pinMode(Echo, INPUT);  
    pinMode(Trig, OUTPUT);  
}  
  
float disMeasure(void)  
{  
    struct timeval tv1;  
    struct timeval tv2;  
    long start, stop;  
    float dis;  
  
    digitalWrite(Trig, LOW);  
    delayMicroseconds(2);  
  
    digitalWrite(Trig, HIGH);  
    delayMicroseconds(10);      //发出超声波脉冲  
    digitalWrite(Trig, LOW);  
      
    while(!(digitalRead(Echo) == 1));  
    gettimeofday(&tv1, NULL);           //获取当前时间  
  
    while(!(digitalRead(Echo) == 0));  
    gettimeofday(&tv2, NULL);           //获取当前时间  
  
    start = tv1.tv_sec * 1000000 + tv1.tv_usec;   //微秒级的时间  
    stop  = tv2.tv_sec * 1000000 + tv2.tv_usec;  
  
    dis = (float)(stop - start) / 1000000 * 34000 / 2;  //求出距离  
  
    return dis;  
}  
  
int main(void)  
{  
    float dis;  
    if(wiringPiSetup() == -1){ //when initialize wiring failed,print messageto screen  
        printf("setup wiringPi failed !");  
        return 1;   
    }  
  
    ultraInit();  
      
    while(1){  
        dis = disMeasure();  
        printf("distance = %0.2f cm\n",dis);  
        delay(1000);  
    }  
  
    return 0;  
}

编译命令:
gcc -Wall -o disMeasure chao.c -lwiringPi

Python版

#coding=utf-8
#导入 GPIO库
import RPi.GPIO as GPIO
import time
  
#设置 GPIO 模式为 BCM
GPIO.setmode(GPIO.BCM)
  
#定义 GPIO 引脚
GPIO_TRIGGER = 23
GPIO_ECHO = 22
  
#设置 GPIO 的工作方式 (IN / OUT)
GPIO.setup(GPIO_TRIGGER, GPIO.OUT)
GPIO.setup(GPIO_ECHO, GPIO.IN)
  
def distance():
    # 发送高电平信号到 Trig 引脚
    GPIO.output(GPIO_TRIGGER, True)
  
    # 持续 10 us 
    time.sleep(0.00001)
    GPIO.output(GPIO_TRIGGER, False)
  
    start_time = time.time()
    stop_time = time.time()
  
    # 记录发送超声波的时刻1
    while GPIO.input(GPIO_ECHO) == 0:
        start_time = time.time()
  
    # 记录接收到返回超声波的时刻2
    while GPIO.input(GPIO_ECHO) == 1:
        stop_time = time.time()
  
    # 计算超声波的往返时间 = 时刻2 - 时刻1
    time_elapsed = stop_time - start_time
    # 声波的速度为 343m/s, 转化为 34300cm/s。
    distance = (time_elapsed * 34300) / 2
  
    return distance
  
if __name__ == '__main__':
    try:
        while True:
            dist = distance()
            print("Measured Distance = {:.2f} cm".format(dist))
            time.sleep(1)
  
        # Reset by pressing CTRL + C
    except KeyboardInterrupt:
        print("Measurement stopped by User")
        GPIO.cleanup()
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