/*
  你可能会用到的函数：
  millis()
  digitalRead();

  附：
  arduino 语法手册：http://arduino.cc/en/Reference/HomePage
*/

#define PIN_key 4    	//按键输入引脚
#define Key_Pressed 0
unsigned long time;		//可供调用的变量

boolean paper_sta = 0;	//可供调用的变量
int paper_num = 0;    	//格数，最后需要打印出的变量

boolean key, key_cache;	//可供调用的变量
boolean getKeyStatus()
{
  return digitalRead(PIN_key);
}

void setup()
{
  Serial.begin(9600);

  pinMode(PIN_key, INPUT_PULLUP);
}

void loop()
{
   //按键检测计数
    if (Key_Pressed == getKeyStatus())
    {
        delay(20);
        if (Key_Pressed == getKeyStatus())
        {
            key = 1;
            if (0 == time)
            {
                time = millis();
                paper_sta = 1;
            }
        }
    }
    else
    {
        if (paper_sta && (1 == key))
        {
            paper_num++;
        }
        key = 0;
    }

    //定时输出
    if ((millis()>=(time + 1000)) && (1 == paper_sta))
    {
        time = 0;
        paper_sta = 0;
        Serial.print("1S内按键的次数为: ");
        Serial.print(paper_num);
        paper_num = 0;
    }
}