#include <Wire.h>

// 定义超声波传感器和RGB LED的引脚
#define TRIG_PIN  9
#define ECHO_PIN  10
#define RED_PIN   3
#define GREEN_PIN 5
#define BLUE_PIN  6

// 定义超声波传感器的速度（厘米/微秒）
#define SOUND_SPEED 0.0343

void setup() {
  pinMode(TRIG_PIN, OUTPUT);
  pinMode(ECHO_PIN, INPUT);
  pinMode(RED_PIN, OUTPUT);
  pinMode(GREEN_PIN, OUTPUT);
  pinMode(BLUE_PIN, OUTPUT);

  Serial.begin(9600); // 开始串口通信
}

void loop() {
  // 发送10微秒的高电平脉冲到TRIG引脚
  digitalWrite(TRIG_PIN, LOW);
  delayMicroseconds(2);
  digitalWrite(TRIG_PIN, HIGH);
  delayMicroseconds(10);
  digitalWrite(TRIG_PIN, LOW);

  // 读取ECHO引脚上的脉冲宽度
  long duration = pulseIn(ECHO_PIN, HIGH);

  // 计算距离
  float distance = duration * SOUND_SPEED / 2;

  // 根据距离调整RGB LED的颜色
  if (distance < 10) {
    // 近距离：红色
    analogWrite(RED_PIN, 255);
    analogWrite(GREEN_PIN, 0);
    analogWrite(BLUE_PIN, 0);
  } else if (distance < 20) {
    // 中距离：蓝色
    analogWrite(RED_PIN, 0);
    analogWrite(GREEN_PIN, 0);
    analogWrite(BLUE_PIN, 255);
  } else {
    // 远距离：绿色
    analogWrite(RED_PIN, 0);
    analogWrite(GREEN_PIN, 255);
    analogWrite(BLUE_PIN, 0);
  }

  // 打印距离到串口监视器
  Serial.print("Distance: ");
  Serial.print(distance);
  Serial.println(" cm");

  delay(100); // 延时100毫秒
}