Home automation bluetooth

code

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

pinMode(8, OUTPUT);  
pinMode(9, OUTPUT);  
pinMode(10, OUTPUT);  
pinMode(11, OUTPUT);  
pinMode(12, OUTPUT);  
pinMode(13, OUTPUT);

}

void loop() 
{
unsigned char x; 

                  digitalWrite(12, 0);delay(1);
                  digitalWrite(11, 0);delay(1);
                  digitalWrite(10, 0);delay(1);
                  digitalWrite( 9, 0);delay(1);
    while(1)
        {
          x=Serial.read();
              if(x=='1')
                {digitalWrite( 9, 1);delay(100);}
             if(x=='A')
                {digitalWrite( 9, 0);delay(100);}
             if(x=='2')
                {digitalWrite(10, 1);delay(100);}
             if(x=='B')
                {digitalWrite(10, 0);delay(100);}
             if(x=='3')
                {digitalWrite(11, 1);delay(100);}
             if(x=='C')
                {digitalWrite(11, 0);delay(100);}
             if(x=='4')
                {digitalWrite(12, 1);delay(100);}
             if(x=='D')
                {digitalWrite(12, 0);delay(100);}


             if(x=='9')
                {
                  digitalWrite(12, 1);delay(100);
                  digitalWrite(11, 1);delay(100);
                  digitalWrite(10, 1);delay(100);
                  digitalWrite( 9, 1);delay(100);
                }
             if(x=='I')
                {
                  digitalWrite(12, 0);delay(100);
                  digitalWrite(11, 0);delay(100);
                  digitalWrite(10, 0);delay(100);
                  digitalWrite( 9, 0);delay(100);
                }
             
                delay(100);
                
        }

}

App link:-https://play.google.com/store/apps/details?id=dev.merahkemarun.arduinobluetoothrelay4ch