Arduino Fire/Security System

1// Include appropriate libraries
2#include <LiquidCrystal.h>
3#include <Keypad.h>
4// LCD Constants
5const int RS = 2;
6const int E = 3;
7const int DB4 = 4;
8const int DB5 = 5;
9const int DB6 = 6;
10const int DB7 = 7;
11
12//Fire/Security component constants
13const int BUZZER = A0;
14const int SMOKE = A1;
15const int BUTTON = A2;
16const int HEAT = A3;
17const int MOTION = A4;
18// Temp sensor constant
19const char DEGREE = (char) 178;
20
21// Keypad constants
22const byte ROWS = 3;
23const byte COLS = 3;
24
25const char KEYMAP[ROWS][COLS] = 
26{
27{'1', '2', '3'},
28{'4', '5', '6'},
29{'7', '8', '9'},  
30};
31byte ROW_PINS[ROWS] = {13, 12, 11}; // Rows 0 to 2 on keypad
32byte COL_PINS[COLS] = {10, 9, 8}; // Columns 0 to 2 on keypad
33// Disarm code
34const String CODE = "1234";
35// Variable to store key press
36char key;
37
38// Instantiate a Keypad object
39Keypad keypad = Keypad(makeKeymap(KEYMAP), ROW_PINS, COL_PINS, ROWS, COLS); 
40// String to store keypad input
41String input = "";
42// Instantiate LCD object
43LiquidCrystal lcd(RS, E, DB4, DB5, DB6, DB7);
44
45// Smoke sensor reading
46int gasValue = 0;
47// Heat detector readings
48int tempValue;
49int tempC;
50// PIR sensor reading
51int pirState;
52// Manual activation reading
53int buttonPress;
54// Alarm type variable
55int alarmType;
56// Variable to determine if alarm is latched
57bool alarmLatched = false;
58// Variables for Code-3 fire tone
59unsigned long previousMillis = 0;
60int code3Step = 0;
61void setup()
62{
63  // Initialize LCD and Cursor
64  lcd.begin(16, 2);
65  lcd.setCursor(0, 0);
66  // Input and Output Pins
67  pinMode(HEAT, INPUT);
68  pinMode(BUZZER, OUTPUT);
69  pinMode(SMOKE, INPUT);
70  pinMode(MOTION, INPUT);
71  pinMode(BUTTON, INPUT);
72 
73}
74
75void playCode3() {
76  unsigned long currentMillis = millis(); // Keep track of ms the program has run for
77
78  int durations[] = {500, 500, 500, 500, 500, 1500}; 
79  // ON, OFF, ON, OFF, ON, OFF(long)
80  // Run the sequence above
81  if (currentMillis - previousMillis >= durations[code3Step]) {
82    previousMillis = currentMillis;
83
84    code3Step++;
85    // Restart the sequence
86    if (code3Step >= 6) {
87      code3Step = 0;
88    }
89
90    // Even steps = ON, Odd = OFF
91    if (code3Step % 2 == 0) {
92      // 520 Hz Low Frequency fire alarm tone
93      tone(BUZZER, 520);
94    } else {
95      noTone(BUZZER);
96    }
97  }
98}
99
100void loop()
101{
102  // Read sensor values
103  pirState = digitalRead(MOTION);
104  gasValue = analogRead(SMOKE);
105  buttonPress = digitalRead(BUTTON);
106  tempValue = analogRead(HEAT);
107  // Map temp value to °C
108  tempC = map(tempValue, 20, 358, -40, 125);
109  
110  // Latch alarm if not latched, then determine alarm type (security or fire)
111  if (!alarmLatched) {
112  	if (pirState == HIGH) {
113    	alarmLatched = true;
114    	alarmType = 1; // security
115  	}
116  	else if (gasValue > 550) {
117    	alarmLatched = true;
118    	alarmType = 2; // fire
119  	}
120  	else if (buttonPress == HIGH) {
121    	alarmLatched = true;
122    	alarmType = 2; // fire
123  	}
124  	else if (tempC > 57) {
125    	alarmLatched = true;
126    	alarmType = 2; // fire
127  	}
128}
129
130  if (alarmLatched) {
131    if (alarmType == 1) {
132  		// SECURITY (constant tone)
133  		tone(BUZZER, 800);
134	} 
135    else {
136  		// FIRE (Code-3)
137  		playCode3();
138	}
139    // Print the appropriate alarm type to the LCD
140  	if (pirState == HIGH) {
141    	lcd.setCursor(0,0);
142    	lcd.print("SECURITY ALARM");
143  	} 
144    else if (gasValue > 550) {
145    	lcd.setCursor(0,0);
146    	lcd.print("FIRE (SMOKE)  ");
147    } 
148    else if (buttonPress == HIGH){
149    	lcd.setCursor(0,0);
150    	lcd.print("FIRE (PULL)   ");
151    }
152    else if (tempC > 57) {
153    	lcd.setCursor(0,0);
154    	lcd.print("FIRE (HEAT)   ");
155    }
156  
157  	// Setup the LCD to enter code to disarm fire/security alarms	
158  	lcd.setCursor(0,1);
159  	lcd.print("ENTER CODE:");
160  	key = keypad.getKey();
161  	// Print the entered keypad keys on the LCD
162  	if (key) {
163  		input += key;              
164  		lcd.setCursor(11,1);
165  		lcd.print(input);         
166  	}
167    // If 4 digit code entered, determine if it is correct
168    if (input.length() == CODE.length()) {
169      	// If the code is correct, turn off buzzer and reset system
170  		if (input == CODE) {
171    		alarmLatched = false;
172    		alarmType = 0;
173    		noTone(BUZZER);
174    		lcd.clear();
175    		lcd.setCursor(0,0);
176    		lcd.print("SYSTEM RESET");
177    		delay(1000);
178    		lcd.clear();
179  		}
180        // Else, clear out the code from the LCD and do not reset system
181  		else {
182    		lcd.setCursor(11,1);
183    		lcd.print("    ");
184    		delay(1000);
185  		}    
186        // After a code is entered, clear out the code from the LCD 
187        input = "";
188       	lcd.setCursor(11,1);
189    }
190  }
191  // If no events, system remains normal
192  else {
193  lcd.setCursor(0,0);
194  lcd.print("SYSTEM NORMAL");  
195  }
196 }