unsigned long period=100;
unsigned long last_time1=0;
unsigned long last_time2=0;
unsigned long last_time3=0;
unsigned long last_time4=0;
#define Pot1 A0
#define LATCH_DIO 4 
#define CLK_DIO 7 
#define DATA_DIO 8 
#define LEDs 10
#define BUTTON1 A1 
#define BUTTON2 A2
#define BUTTON3 A3
#define buzzer 3
long timeset=500;
boolean led;
int num;
const byte SEGMENT_MAP [] = {0xC0 , 0xF9 , 0xA4 , 0xB0 , 0x99 , 0x92 , 0x82 , 0xF8 , 0X80 , 0X90} ;
const byte SEGMENT_SELECT [ ] = { 0xF1 , 0xF2 , 0xF4 , 0xF8 } ; 
void setup ( ) {
  Serial.begin(9600);
  pinMode (LATCH_DIO,OUTPUT) ;
  pinMode (CLK_DIO,OUTPUT) ; 
  pinMode ( DATA_DIO,OUTPUT ) ;
  pinMode (LEDs,OUTPUT);
  pinMode (buzzer,OUTPUT);
  digitalWrite(buzzer,HIGH);
} 
void loop () {
  chk_sw();
  int data=analogRead(Pot1);
  if(num==1){
    if(data<500){
      Serial.println(data);
    tone(buzzer,500,1);
      }
    }
    if(!digitalRead(BUTTON3)){
        num=3;
        noTone(buzzer);
      }
  if (num==2){}
  WriteNumberToSegment(3,data%10);
  WriteNumberToSegment(2,(data%100)/10);
  WriteNumberToSegment(1,(data%1000)/100);
  WriteNumberToSegment(0,data/1000);
}


void WriteNumberToSegment ( byte Segment , byte Value ) { 
  digitalWrite (LATCH_DIO,LOW) ; 
  shiftOut ( DATA_DIO , CLK_DIO , MSBFIRST , SEGMENT_MAP [ Value ] ) ; 
  shiftOut ( DATA_DIO , CLK_DIO , MSBFIRST , SEGMENT_SELECT [ Segment ] ) ; 
  digitalWrite ( LATCH_DIO , HIGH ) ;
  millis();
}
void chk_sw(){

    if(!digitalRead(BUTTON1)){
      num=1;
    Serial.println(num);
    }
    if(!digitalRead(BUTTON2)){
      num=2;
    Serial.println(num);
    }
    if(!digitalRead(BUTTON3)){
      num=3;
    Serial.println(num);
  }
}