设计一个由单独按键启、停、清零的秒表。秒表时间范围为100秒（00~99），显示用数码管右边两位显示。单独按键为K5，此按键按下一次，启动秒表；再按一次，暂停秒表；再按一次，秒表清零。同时，在按键的时候用“哔”声提示。

这是一个简单的秒表设计，我们可以使用Arduino Uno控制板和数码管模块来构建它。以下是代码示例：

// 定义数码管引脚
const int digitPins[2] = {9, 10};
const int segmentPins[8] = {2, 3, 4, 5, 6, 7, 8, 11};

// 定义按钮引脚
const int buttonPin = 12;

// 定义秒表计数器和状态标记
int counter = 0;
bool isRunning = false;

void setup() {
  // 初始化引脚
  for (int i = 0; i < 2; i++) {
    pinMode(digitPins[i], OUTPUT);
  }
  for (int i = 0; i < 8; i++) {
    pinMode(segmentPins[i], OUTPUT);
  }
  pinMode(buttonPin, INPUT_PULLUP);
}

void loop() {
  // 读取按钮状态
  bool buttonState = digitalRead(buttonPin) == LOW;

  // 如果按钮按下
  if (buttonState) {
    // 播放“哔”声音
    tone(13, 1000, 200);

    // 如果秒表正在运行，暂停并显示结果
    if (isRunning) {
      isRunning = false;
      displayNumber(counter);
    }
    // 否则开始或重置秒表
    else {
      isRunning = true;
      counter = 0;
      displayNumber(counter);
    }
  }

  // 如果秒表正在运行，计数器加一
  if (isRunning) {
    counter++;
    // 如果计数器超过100，重置为0
    if (counter >= 100) {
      counter = 0;
    }
    displayNumber(counter);
    delay(1000);
  }
}

// 显示数字
void displayNumber(int number) {
  // 分离十位和个位
  int digit1 = number / 10;
  int digit2 = number % 10;
  // 显示数码管
  digitalWrite(digitPins[0], LOW);
  digitalWrite(digitPins[1], HIGH);
  displayDigit(digit1);
  delay(5);
  digitalWrite(digitPins[0], HIGH);
  digitalWrite(digitPins[1], LOW);
  displayDigit(digit2);
  delay(5);
}

// 显示单个数字
void displayDigit(int digit) {
  switch (digit) {
    case 0:
      digitalWrite(segmentPins[0], LOW);
      digitalWrite(segmentPins[1], LOW);
      digitalWrite(segmentPins[2], LOW);
      digitalWrite(segmentPins[3], LOW);
      digitalWrite(segmentPins[4], LOW);
      digitalWrite(segmentPins[5], LOW);
      digitalWrite(segmentPins[6], HIGH);
      break;
    case 1:
      digitalWrite(segmentPins[0], HIGH);
      digitalWrite(segmentPins[1], LOW);
      digitalWrite(segmentPins[2], LOW);
      digitalWrite(segmentPins[3], HIGH);
      digitalWrite(segmentPins[4], HIGH);
      digitalWrite(segmentPins[5], HIGH);
      digitalWrite(segmentPins[6], HIGH);
      break;
    case 2:
      digitalWrite(segmentPins[0], LOW);
      digitalWrite(segmentPins[1], LOW);
      digitalWrite(segmentPins[2], HIGH);
      digitalWrite(segmentPins[3], LOW);
      digitalWrite(segmentPins[4], LOW);
      digitalWrite(segmentPins[5], HIGH);
      digitalWrite(segmentPins[6], LOW);
      break;
    case 3:
      digitalWrite(segmentPins[0], LOW);
      digitalWrite(segmentPins[1], LOW);
      digitalWrite(segmentPins[2], LOW);
      digitalWrite(segmentPins[3], LOW);
      digitalWrite(segmentPins[4], HIGH);
      digitalWrite(segmentPins[5], HIGH);
      digitalWrite(segmentPins[6], LOW);
      break;
    case 4:
      digitalWrite(segmentPins[0], HIGH);
      digitalWrite(segmentPins[1], LOW);
      digitalWrite(segmentPins[2], LOW);
      digitalWrite(segmentPins[3], HIGH);
      digitalWrite(segmentPins[4], HIGH);
      digitalWrite(segmentPins[5], LOW);
      digitalWrite(segmentPins[6], LOW);
      break;
    case 5:
      digitalWrite(segmentPins[0], LOW);
      digitalWrite(segmentPins[1], HIGH);
      digitalWrite(segmentPins[2], LOW);
      digitalWrite(segmentPins[3], LOW);
      digitalWrite(segmentPins[4], HIGH);
      digitalWrite(segmentPins[5], LOW);
      digitalWrite(segmentPins[6], LOW);
      break;
    case 6:
      digitalWrite(segmentPins[0], LOW);
      digitalWrite(segmentPins[1], HIGH);
      digitalWrite(segmentPins[2], LOW);
      digitalWrite(segmentPins[3], LOW);
      digitalWrite(segmentPins[4], LOW);
      digitalWrite(segmentPins[5], LOW);
      digitalWrite(segmentPins[6], LOW);
      break;
    case 7:
      digitalWrite(segmentPins[0], LOW);
      digitalWrite(segmentPins[1], LOW);
      digitalWrite(segmentPins[2], LOW);
      digitalWrite(segmentPins[3], HIGH);
      digitalWrite(segmentPins[4], HIGH);
      digitalWrite(segmentPins[5], HIGH);
      digitalWrite(segmentPins[6], HIGH);
      break;
    case 8:
      digitalWrite(segmentPins[0], LOW);
      digitalWrite(segmentPins[1], LOW);
      digitalWrite(segmentPins[2], LOW);
      digitalWrite(segmentPins[3], LOW);
      digitalWrite(segmentPins[4], LOW);
      digitalWrite(segmentPins[5], LOW);
      digitalWrite(segmentPins[6], LOW);
      break;
    case 9:
      digitalWrite(segmentPins[0], LOW);
      digitalWrite(segmentPins[1], LOW);
      digitalWrite(segmentPins[2], LOW);
      digitalWrite(segmentPins[3], LOW);
      digitalWrite(segmentPins[4], HIGH);
      digitalWrite(segmentPins[5], LOW);
      digitalWrite(segmentPins[6], LOW);
      break;
  }
}

请注意，此代码假定您已经将数码管模块正确连接到Arduino板上。在编写代码之前，请务必仔细阅读数码管模块的数据手册。