Home automation with Arduino

1#include<SoftwareSerial.h>
2SoftwareSerial BTserial(3,2); // TX|RX
3//Declaration  of variables
4String msg = "";
5String v1 = "";
6
7int light_1 = 11;
8int  light_2 = 10;
9int light_3 = 9;
10int light_4 = 8;
11void setup() {
12  //  put your setup code here, to run once:
13  //set up our serial and bluetooth serial  monitors
14  Serial.begin(9600);
15  BTserial.begin(9600);
16}
17
18void loop()  {
19  // put your main code here, to run repeatedly:
20  // check it bluetooth  serial is connected and available
21  if (BTserial.available() > 0){
22  msg =  BTserial.parseInt();// decode the integer sent from phone through BT serial.
23  }
24  // check the integer and give corresponding output
25  if(msg == "11"){
26    digitalWrite(light_1,LOW);
27    }
28  if(msg == "10"){
29    digitalWrite(light_1,HIGH);
30    }
31   if(msg == "21"){
32    digitalWrite(light_2,LOW);
33    }
34    if(msg  == "20"){
35    digitalWrite(light_2,HIGH);
36    }
37     if(msg == "31"){
38    digitalWrite(light_3,LOW);
39    }
40     if(msg == "30"){
41    digitalWrite(light_3,HIGH);
42    }
43    if(msg == "41"){
44    digitalWrite(light_4,LOW);
45    }
46     if(msg  == "40"){
47    digitalWrite(light_4,HIGH);
48    }
49  Serial.println(v1);
50  delay(500);
51}