main.cpp

00001 #include "mbed.h"       // Library for mbed
00002 #include "Servo.h"      // Library for servo motor
00003 #include "Keypad.h"     // Library for 4x4 matrix keypad
00004 #include "TextLCD.h"    // Library for 16x2 LCD
00005 #include <string>       // Library for string class
00006 
00007 Servo myservo(PTB3);            // Signal pin of servo motor attach to pin PTB3 
00008 DigitalIn IR_sensor(PTA12);     // IR obstacle sensor connect to digital pin PTA12
00009 DigitalOut LED(PTD4);           // Green LED connect to digital pin PTD4
00010 DigitalOut LCD(PTC12);          // Cathode pin of LCD connect to PTC12
00011 
00012 // Keypad connection (col 0, col1, col2, col3, row0, row1, row2, row3)
00013 Keypad keypad(PTC9,PTC8,PTA5,PTA4,PTD2,PTD0,PTD5,PTA13);
00014 // LCD connection ( RS, E, D4, D5, D6, D7)
00015 TextLCD lcd(PTE20, PTE21, PTE22, PTE23, PTE29, PTE30, TextLCD::LCD16x2); 
00016 
00017 char pass_set[4] = {'1','2','3','4'};   // Predefined password
00018 char password[4] ;                      // String used to store password input
00019 
00020 int main() {                    // Main function
00021     char key, old_key;          // Declare char variables key and old_key
00022     int i=0,j=0;                // Declare integer variables i and j and initialize to 0
00023     int released = 1;           // Declare integer variable ‘released’ used to indicate whether the key is pressed
00024     int ret = 2;                // Declare integer variable ‘ret’ used for comparison of predefined password and input password
00025     myservo = 0.0;              // Initialize the position of servo motor to 0 (locked) 
00026     lcd.cls();                  // Clear the LCD
00027     
00028     while(IR_sensor == 1){      // No obstacle detected, IR_sensor returns 1
00029         LED = 0;                // Green LED turns off
00030         LCD = 1;                // Backlight of LCD turns off
00031     }
00032     // While loop is break once the IR_sensor returns 0 which means obstacle is detected 
00033     LED = 1;                        // Green LED turns on
00034     LCD = 0;                        // Backlight of LCD turns on
00035     lcd.printf("Welcome Home!");    // Print welcome message
00036     lcd.locate(0,1);                // Print message on second line
00037     lcd.printf("Enter Password.");  // Ask user to enter password
00038     wait(2);                        // Wait for 2 seconds
00039     lcd.cls();
00040     lcd.printf("Password Entered");
00041     
00042     while(1) {                      // Infinite loop
00043        key = keypad.ReadKey();      // Read the current key pressed from the keypad
00044        
00045         if (key == '\0'){           // If no key is pressed or all the keys are released
00046             released = 1;}          // Set the released
00047         
00048         if ((key != '\0') && (released == 1)){  //If a key is pressed and previous key is released
00049            if (key != old_key){                 // If the key pressed is different as the previous key
00050                 password[i++] = key;            // Store the input key in password string
00051                 lcd.locate(j++,1);              // Print the key pressed on LCD
00052                 lcd.printf("%c",key);
00053                 old_key = key;                  // Store the latest key pressed on old_key
00054                 released = 0;}                  // Clear the flag indicate the key is still pressed
00055         }
00056         
00057        if (i == 4){                  // If the number of keys pressed is equal to 4
00058             // Compare the input password with predefined password
00059             // 4 is the number of character to be compared
00060             ret = strncmp(password, pass_set, 4); 
00061             wait(0.5);               // Wait for 0.5 seconds
00062         }
00063         
00064        if (ret ==0){                        // The input password matches the predefined password
00065            lcd.cls();                       // Print message on LCD
00066            lcd.printf("Password Correct");
00067            lcd.locate(0,1);
00068            lcd.printf("Access Allowed.");
00069            myservo = 1.0;                   // Rotate the servo motor to unlock the door
00070            wait(2);                         // Wait for 2 seconds
00071            main();                          // Jump back to main function to start everything again
00072         }
00073         else if (ret ==1){                  // The input password does not matches the predefined password
00074            lcd.cls();                        // Print message on LCD
00075            lcd.printf("Wrong Password.");
00076            lcd.locate(0,1);
00077            lcd.printf("Access Denied.");
00078            wait(2);                         // Wait for 2 seconds
00079            main();                          // Jump back to main function to start everything again
00080         } 
00081     }
00082 }