//Master//

#include <LiquidCrystal.h>
#include <Wire.h>
#define SLAVE_ADDR 8

LiquidCrystal lcd(3,4,5,6,7,8);
int volume;

void setup()	{
	
	Wire.begin();
	Serial.begin(115200);
	lcd.begin(16, 2);
	lcd.clear();
	lcd.print("Volume:");
	lcd.setCursor(0,1);
}
void loop()	{
	
	delay(2000);
	int16_t vol;
	byte a,b;
	Wire.requestFrom(8,2);
    a = Wire.read(); // receive a byte as character
	b = Wire.read();
	volume = a;
	volume = (volume<<8)|b;
    lcd.setCursor(1,1);
    lcd.print(vol);
    lcd.print(" %");
	Serial.println(vol);         // print the character
	lcd.write(1);
}


//Slave//
#include <Wire.h>
#define pulse_ip 9
#define SLAVE_ADDR 8
int ontime,offtime,volume,Fdiff;
float freq,period,temp,adc_val;
int Fmin = 6000;
int Fmax = 9100;

void setup(){
	
	pinMode(pulse_ip,INPUT);
	Wire.begin(8);                // join i2c bus with address #8
	Wire.onRequest(requestEvent); // register event
  }
void loop(){
delay(100);
}
void requestEvent(){
   ontime = pulseIn(pulse_ip,HIGH);
   offtime = pulseIn(pulse_ip,LOW);
   period = ontime+offtime;
   freq = 1000000.0/period;
   if(period==0){ 
    freq=0;
    }
     adc_val=analogRead(A1); // temperature readings
     temp=(adc_val4.85)/10;
     Fdiff = Fmax - Fmin;
     volume = ((Fmax-freq)/Fdiff)*100;
	 
	 int16_t vol = volume;
	 byte myArray[2];
	 myArray[0] = (vol>>8)&amp; 0xFF;
	 myArray[1] = vol & 0xFF;
     Wire.write(myArray,2);
	 delay(200);
}