#include <LedControl.h>

// 定义触发和回声引脚
const int trigPin = 7;
const int echoPin = 8;

// 定义LED灯的引脚
const int led1 = 2;
const int led2 = 3;
const int led3 = 4;
const int led4 = 5;

void setup() {
  // 初始化串行通讯
  Serial.begin(9600);
  
  // 设置传感器引脚模式
  pinMode(trigPin, OUTPUT);
  pinMode(echoPin, INPUT);
  
  // 设置LED引脚为输出模式
  pinMode(led1, OUTPUT);
  pinMode(led2, OUTPUT);
  pinMode(led3, OUTPUT);
  pinMode(led4, OUTPUT);
}

void loop() {
  long duration, cm;

  // 触发超声波传感器
  digitalWrite(trigPin, LOW);
  delayMicroseconds(2);
  digitalWrite(trigPin, HIGH);
  delayMicroseconds(10);
  digitalWrite(trigPin, LOW);

  // 读取回声时间
  duration = pulseIn(echoPin, HIGH);
  cm = microsecondsToCentimeters(duration);

  // 根据距离控制LED灯
  controlLEDs(cm);

  // 打印距离
  Serial.print(cm);
  Serial.println(" cm");
  
  delay(100);
}

long microsecondsToCentimeters(long microseconds) {
  return microseconds / 29 / 2;
}

void controlLEDs(long cm) {
  // 根据距离决定点亮多少个LED
  if (cm < 100) {
    digitalWrite(led1, HIGH);
    digitalWrite(led2, LOW);
    digitalWrite(led3, LOW);
    digitalWrite(led4, LOW);
  } else if (cm < 200) {
    digitalWrite(led1, HIGH);
    digitalWrite(led2, HIGH);
    digitalWrite(led3, LOW);
    digitalWrite(led4, LOW);
  } else if (cm < 300) {
    digitalWrite(led1, HIGH);
    digitalWrite(led2, HIGH);
    digitalWrite(led3, HIGH);
    digitalWrite(led4, LOW);
  } else {
    digitalWrite(led1, HIGH);
    digitalWrite(led2, HIGH);
    digitalWrite(led3, HIGH);
    digitalWrite(led4, HIGH);
  }
}