DIY Bi-Directional Counter using Arduino & IR Sensors

1#include <LiquidCrystal_I2C.h> 
2// Initialize the LCD with I2C address 0x27 
3LiquidCrystal_I2C lcd(0x27, 16, 2); 
4const int irPin1 = 2; // IR sensor 1(Entrance Detector) connected to digital pin 2 
5const int irPin2 = 3; // IR sensor 2(Exit Detector) connected to digital pin 3 
6int in_count = 0;        // Variable to store the number of people went inside 
7int out_count = 0;       // Variable to store the number of people went outside 
8int current_count = 0;   // Variable to store the current number of people present inside 
9const unsigned long timeout = 50; // Object detection Timeout period in milliseconds 
10void setup() { 
11	 /* Initialise LCD Display */ 
12	 lcd.init(); 
13	 lcd.backlight(); 
14	 lcd.setCursor(0, 0); 
15	 lcd.print("IN: 0   OUT: 0"); 
16	 lcd.setCursor(0, 1); 
17	 lcd.print("Current: 0"); 
18	 
19	 /* Pull up the input pins */ 
20	 pinMode(irPin1, INPUT_PULLUP); 
21	 pinMode(irPin2, INPUT_PULLUP); 
22} 
23void loop() { 
24	 /*  Check if the first sensor is triggered */ 
25	 if (digitalRead(irPin1) == LOW) { 
26	   unsigned long startTime = millis(); 
27	   while ((millis() - startTime) < timeout) { 
28	     if(digitalRead(irPin2) == LOW){ 
29	        ++in_count; 
30	        updateDisplay(); 
31	        break; 
32	     } 
33	   } 
34	   //wait until both sensors return to a normal state 
35	   while(!digitalRead(irPin1) || !digitalRead(irPin2)); 
36	 } 
37	  
38	 /* Check if the second sensor is triggered */ 
39	 else if (digitalRead(irPin2) == LOW) { 
40	   unsigned long startTime = millis(); 
41	   while ((millis() - startTime) < timeout) { 
42	     if(digitalRead(irPin1) == LOW){ 
43	       if(out_count < in_count){ 
44	          ++out_count; 
45	          updateDisplay(); 
46	          break; 
47	       } 
48	     } 
49	   } 
50	   //wait until both sensors return to a normal state 
51	   while(!digitalRead(irPin1) || !digitalRead(irPin2)); 
52	 } 
53	 
54} 
55void updateDisplay() { 
56	 lcd.setCursor(4, 0); 
57	 lcd.print("   "); 
58	 lcd.setCursor(4, 0); 
59	 lcd.print(in_count); 
60	 lcd.setCursor(13, 0); 
61	 lcd.print("   "); 
62	 lcd.setCursor(13, 0); 
63	 lcd.print(out_count); 
64	 current_count = in_count - out_count; 
65	 lcd.setCursor(9, 1); 
66	 lcd.print("   "); 
67	 lcd.setCursor(9, 1); 
68	 lcd.print(current_count); 
69}