#include <LiquidCrystal.h>
LiquidCrystal lcd(8, 9, 4, 5, 6, 7);
volatile int count=0;
long debounce_time=0;
long debounce=300;
double freq=1;
static const int LED_PIN=13;
static const int digital_pin=2;
bool previousButtonState=HIGH;
void interrupt_handle(){
  if(millis()-debounce_time>debounce){
  freq=freq+freq*1/10;
  delay(20);
  Serial.print(freq);
   delay(20);
  Serial.println();
  }
  debounce_time=0;
}
void led_miganie(int freq){
  digitalWrite(LED_PIN,HIGH);
  delay(60/freq);
  digitalWrite(LED_PIN,LOW);
  delay(60/freq);

}
void setup() {
  // put your setup code here, to run once:
  Serial.begin(9600);
  lcd.begin(16, 2);
  lcd.print("waiting...");
  pinMode(digital_pin,INPUT);
  pinMode(LED_PIN,OUTPUT);
  //attachInterrupt(digitalPinToInterrupt(digital_pin), interrupt_handle, FALLING);
}

void loop() {
  // put your main code here, to run repeatedly:
  bool currentButtonState=digitalRead(digital_pin);
  if((currentButtonState==LOW)&&(previousButtonState==HIGH)){
    interrupt_handle();
  }
  if(Serial.available()>0){
  freq=1;
  Serial.read();
  Serial.print(freq);
   delay(20);
  Serial.println();
  }
  previousButtonState=currentButtonState;
  led_miganie(freq);
}