Control AC Load with Voice Commands

1String voice;
2
3#define r1 5
4int relay1 = LOW;
5#define r2 6
6int  relay2 = LOW;
7#define r3 7
8int relay3 = LOW;
9#define r4 8
10int relay4  = LOW;
11void setup() 
12{                                           
13  Serial.begin(9600);
14   pinMode(r1, OUTPUT); 
15    pinMode(r2, OUTPUT);
16    pinMode(r3, OUTPUT);  
17    pinMode(r4, OUTPUT);
18 }
19void loop() {
20 while (Serial.available())   //Check if there is an available byte to read
21  {                            
22  delay(10);                   //Delay added to make thing stable
23  char c =  Serial.read();      //Conduct a serial read
24  voice += c;                  //Shorthand  for voice = voice + c
25  } 
26
27  if (voice.length() > 0) 
28  {
29    Serial.println(voice);
30   if(voice == "all off")                             
31     {
32            digitalWrite(r1,0);
33            digitalWrite(r2,0);  //all off
34            digitalWrite(r3,0);
35            digitalWrite(r4,0);
36            delay(250);
37     }  
38  else  if(voice == "fan")                              
39     {
40    
41            relay1  = ~ relay1;
42            digitalWrite(r1,relay1);
43            delay(250);
44     }
45  else if(voice == "light")                              
46     {
47            relay2 = ~ relay2;
48            digitalWrite(r2,relay2);
49            delay(250);
50     }
51  else if(voice == "lamp")                              
52     {
53            relay3 = ~ relay3;
54            digitalWrite(r3,relay3);
55            delay(250);
56     }
57      else if(voice == "tubelight")                              
58     {
59             relay4 = ~ relay4;
60            digitalWrite(r4,relay4);
61            delay(250);
62     }
63  voice="";                                                       //Reset  the variable after initiating
64  }}