HC-SR04 模块实现超声波测距代码

HC-SR04是一种常见的超声波传感器模块，常用于非接触式的距离测量。它的工作原理是通过发送超声波脉冲然后接收反射回来的信号，计算出两点之间的距离。以下是使用Python编写的基本HC-SR04测距代码示例，假设已连接到GPIO针脚：

import RPi.GPIO as GPIO
import time

# 设置GPIO引脚
TRIG_PIN = 18
ECHO_PIN = 23

def setup():
    GPIO.setmode(GPIO.BCM)
    GPIO.setup(TRIG_PIN, GPIO.OUT)  # TRIG作为输出
    GPIO.setup(ECHO_PIN, GPIO.IN)   # ECHO作为输入

def distance_cm():
    GPIO.output(TRIG_PIN, False)
    time.sleep(2)

    GPIO.output(TRIG_PIN, True)
    time.sleep(0.00001)
    GPIO.output(TRIG_PIN, False)

    start_time = time.time()
    while GPIO.input(ECHO_PIN) == 0:
        start_time = time.time()

    stop_time = time.time()
    while GPIO.input(ECHO_PIN) == 1:
        stop_time = time.time()

    elapsed_time = stop_time - start_time
    distance = (elapsed_time * 34300) / 2  # 速度34300 cm/s，在空气中近似

    return round(distance, 2)

if __name__ == "__main__":
    try:
        while True:
            print(f"Distance: {distance_cm()} cm")
            time.sleep(1)  # 控制测量频率
    except KeyboardInterrupt:
        GPIO.cleanup()  # 退出时清理GPIO资源