Automatic Temperature-Adjusting Fan

1#include <LiquidCrystal.h>
2
3//motor
4const int DC_MOTOR = 3;
5
6//LCD
7const int RS = 4;
8const int E = 5;
9const int DB4 = 6;
10const int DB5 = 7;
11const int DB6 = 8;
12const int DB7 = 9;
13
14//temp sensor
15const int TEMP_SENSOR = A0;
16
17//LED
18const int RED_LED = 10;
19const int BLUE_LED = 11;
20const int GREEN_LED = 12;
21
22//degree character
23const char DEGREE = (char) 178;
24
25//initialize LCD
26LiquidCrystal lcd(RS, E, DB4, DB5, DB6, DB7);
27int tempC;
28
29void setup()
30{
31  pinMode(DC_MOTOR, OUTPUT); //motor
32  lcd.begin(16, 2); //lcd
33  pinMode(TEMP_SENSOR, INPUT); //temp sensor
34  for (int i = RED_LED; i <= GREEN_LED; i++) //LEDs
35    pinMode(i, OUTPUT);
36  
37  //print never-changing text to LCD
38  lcd.print("TEMP: ");
39}
40
41void loop()
42{
43  //read sensor value 20-358
44  int tempSensorValue = analogRead(TEMP_SENSOR);
45  // map sensor value 20-358 to -40 to 125
46  tempC = map(tempSensorValue, 20, 358, -40, 125);
47  
48    
49  //if-else chain to decide color, LCD screen, and fan speed
50  if (tempC <= 20) {
51     writeToLCD(tempC, "COLD!     "); 
52     analogWrite(DC_MOTOR, 0);
53     digitalWrite(RED_LED, LOW);
54     digitalWrite(BLUE_LED, HIGH);
55     digitalWrite(GREEN_LED, HIGH);
56  } else if (tempC <= 25) {
57     writeToLCD(tempC, "SEMI-WARM   "); 
58     analogWrite(DC_MOTOR, .25 * 255);
59     digitalWrite(RED_LED, LOW);
60     digitalWrite(BLUE_LED, HIGH);
61     digitalWrite(GREEN_LED, LOW);
62  } else if (tempC <= 32) {
63     writeToLCD(tempC, "WARM       "); 
64     analogWrite(DC_MOTOR, .50 * 255);
65     digitalWrite(RED_LED, LOW);
66     digitalWrite(BLUE_LED, LOW);
67     digitalWrite(GREEN_LED, HIGH);
68  } else if (tempC <= 38) {
69     writeToLCD(tempC, "HOT       "); 
70     analogWrite(DC_MOTOR, .75 * 255);
71     digitalWrite(RED_LED, HIGH);
72     digitalWrite(BLUE_LED, HIGH);
73     digitalWrite(GREEN_LED, LOW);
74  } else {
75     writeToLCD(tempC, "EXTREME    "); 
76     analogWrite(DC_MOTOR, 255);
77     digitalWrite(RED_LED, HIGH);
78     digitalWrite(BLUE_LED, LOW);
79     digitalWrite(GREEN_LED, LOW);
80  }
81  
82}
83
84//function to write text to the LCD since the location never changes
85void writeToLCD(int temp, String tempDesc) {
86  lcd.setCursor(6, 0);
87  lcd.print(temp);
88  lcd.print(DEGREE);
89  lcd.print("C        ");
90  lcd.setCursor(0, 1);
91  lcd.print(tempDesc);
92}