Make an Inverter at Home Using Arduino

#include "TimerOne.h"               // include TimerOne.h
#define low_battery_voltage 10.2               // define high battery voltage limit as 14.2
#define high_battery_voltage 14.4               // define low battery voltage limit as 10.2
int dutycycle = 0;               // Initailize duty cylce variable as integer data type
int sense_value =0;               // Initialize sense_value variable to capture the adc reading of battery voltage (range from 0 to 1023)
float battery_voltage = 0.0;               // Initialize battery_voltage variable as a float data type to convert sense_value to actual battery voltage
                                                 
                                                 
void setup()               // Setup function
{
  pinMode (9,OUTPUT);              // set pin 9 as an output pin for pwm
  pinMode (10,OUTPUT);             // set pin 10 as an output pin for pwm 
  Timer1.initialize(20000);             // Initailize timer1 time period as 20 milli second (50 Hz frequency)
  Timer1.attachInterrupt(battery_voltage_measurement);      // battery_voltage_measurement function will be executed every 20 milli second using timer 1 overflow interrupt
  TCCR1A = (TCCR1A & 0x0F) | 0xB0 ;             // set pin 10 inverted of pin 9
}  
   
void battery_voltage_measurement()               // battery_voltage_measurement function starts
{ sense_value = (analogRead(A0));               // read battery voltage on pin A0 & capture that value in sense_value variable
                                             // {warning - arduino pin accept only upto 5v so don't forget to map upper 
                                             //  battery volatge i.e 14.2v to 5v using voltage divider resistor network}
                                                 
 battery_voltage = sense_value * (14.4/1023.0);               // convert sense_value (0 to 1023) to range (0 to 14.2)
 if(battery_voltage < 14.4 && battery_voltage > 10.2) // if battery voltage is under limit i.e between 10.2 and 14.2 then dutycycle will be 150
        {
          dutycycle = 300;
        }
                                                 
                                                
 else if(battery_voltage < 10.2 || battery_voltage > 14.4)              // if battery voltage is below 10.2v or above 14.2v , 
       {
          dutycycle = 0;         //set the duty cycle to 0 and inverter will go in cutoff mode
       }                                      
                                                 
                                                
}              // battery_voltage_measurement function ends
                                                 
                                                 
 void loop()              // loop function starts
{
  Timer1.pwm(9,dutycycle,20000);              // Timer1.pwm function takes argument as (pin no. , dutycycle , time period)
  Timer1.pwm(10,1024-dutycycle,20000);                         
                                                                          
}               // loop function ends