Marker Beacon System with IR Sensors, Buzzer and LED

1int irInner=6,irMiddle=7,irOuter=8,irRunway=10;
2int ledInner=4,ledMiddle=2,ledOuter=3;
3int  sound = 11;              // Declaration of variables with pin numbers of components
4int  valIn=0,valMd=0,valOt=0,valRunway=0;
5int check1=0, check2=0, check3=0;  // Declaration  and initialization of variables
6
7void setup()
8{
9  
10  Serial.begin(9600);
11  
12  pinMode(irInner, INPUT_PULLUP);  // input component
13  pinMode(ledInner,  OUTPUT);       //output component
14  
15   pinMode(irMiddle, INPUT_PULLUP);
16  pinMode(ledMiddle, OUTPUT);
17  
18   pinMode(irOuter, INPUT_PULLUP);
19  pinMode(ledOuter,  OUTPUT);
20
21  pinMode(irRunway,INPUT_PULLUP); 
22  
23}
24
25void loop()
26{
27  
28  valIn=digitalRead(irInner);  //getting current state of sensor(HIGH or LOW)
29  valMd=digitalRead(irMiddle);
30  valOt=digitalRead(irOuter);
31  valRunway=digitalRead(irRunway);
32
33
34      if(valOt==LOW  )  //if obstacle on outer sensor
35      {
36        digitalWrite(ledOuter,  HIGH); //led on
37        check1=1;
38      }
39      else
40      {
41        digitalWrite(ledOuter,LOW);  //led off
42      }
43
44  
45      if(valMd==LOW )
46      { 
47        digitalWrite(ledMiddle,  HIGH);
48        check1=0;
49        check2=1;
50      }
51      else
52      {
53        digitalWrite(ledMiddle, LOW);
54      }
55     
56      
57      if(valIn==LOW  )
58      {  
59        digitalWrite(ledInner, HIGH);
60        check3=1;
61        check2=0;
62      } 
63      else
64      {
65        digitalWrite(ledInner,  LOW);
66      }
67
68       if(valRunway==LOW)
69       {
70       check3=0;
71        delay(6000);  //programme execution delay for 6 sec
72       }
73
74  
75      if(check1==1) //
76      {
77        tone(sound, 1000, 350); //buzzer  or speaker making sound
78        delay(500);
79      }
80      if(check2==1)
81      {
82        tone(sounds, 4000, 100);
83        delay(150);
84        tone(sounds,  1000, 150);
85        delay(300);
86
87      }
88      if(check3==1)
89      {
90          tone(sound, 4000, 100);
91        delay(150);
92      }
93      
94}