用三个按键控制led流水灯，呼吸灯，跑马灯三种状态

以下是一个基于 Arduino 的示例代码，使用三个按钮控制 LED 流水灯、呼吸灯和跑马灯三种状态：

// 定义引脚
const int BUTTON1_PIN = 2;
const int BUTTON2_PIN = 3;
const int BUTTON3_PIN = 4;
const int LED_PIN = 5;

// 定义状态
enum State {
  STATE_FLOWING,
  STATE_BREATHING,
  STATE_RUNNING
};

// 初始化状态
State state = STATE_FLOWING;

void setup() {
  // 设置引脚模式
  pinMode(BUTTON1_PIN, INPUT_PULLUP);
  pinMode(BUTTON2_PIN, INPUT_PULLUP);
  pinMode(BUTTON3_PIN, INPUT_PULLUP);
  pinMode(LED_PIN, OUTPUT);
}

void loop() {
  switch (state) {
    case STATE_FLOWING:
      flowing();
      break;
    case STATE_BREATHING:
      breathing();
      break;
    case STATE_RUNNING:
      running();
      break;
  }

  // 检测按钮状态
  if (digitalRead(BUTTON1_PIN) == LOW) {
    state = STATE_FLOWING;
  } else if (digitalRead(BUTTON2_PIN) == LOW) {
    state = STATE_BREATHING;
  } else if (digitalRead(BUTTON3_PIN) == LOW) {
    state = STATE_RUNNING;
  }
}

void flowing() {
  // LED 流水灯，每隔 100 毫秒亮一个 LED
  digitalWrite(LED_PIN, HIGH);
  delay(100);
  digitalWrite(LED_PIN, LOW);
  delay(100);
}

void breathing() {
  // LED 呼吸灯，每隔 10 毫秒改变亮度
  for (int i = 0; i < 255; i++) {
    analogWrite(LED_PIN, i);
    delay(10);
  }
  for (int i = 255; i >= 0; i--) {
    analogWrite(LED_PIN, i);
    delay(10);
  }
}

void running() {
  // LED 跑马灯，每隔 200 毫秒依次亮两个 LED
  digitalWrite(LED_PIN, HIGH);
  delay(200);
  digitalWrite(LED_PIN, LOW);
  delay(200);
  digitalWrite(LED_PIN, HIGH);
  delay(200);
  digitalWrite(LED_PIN, LOW);
  delay(200);
}

在这个示例代码中，我们使用 `digitalRead` 函数来检测三个按钮的状态，如果检测到按钮被按下，则改变状态。每个状态对应一个函数，分别实现了 LED 流水灯、呼吸灯和跑马灯的效果。你可以根据需要调整每个状态的实现方式和时间间隔。