Climate Chamber System

1// load libraries
2#include "DHT.h"
3#include "U8glib.h"
4U8GLIB_SSD1306_128X64  u8g(U8G_I2C_OPT_NONE | U8G_I2C_OPT_DEV_0);
5
6//set Pin for T/RH Sensor and  specify type, give character string for output
7#define DHTPIN 2
8#define DHTTYPE  DHT22
9DHT dht(DHTPIN, DHTTYPE);
10char str [10];
11
12//Hardware Pins
13const  int Fog = 3; //nebulisers
14const int Fan = 6; //CPU Fans for air circulation
15const  int OK = 7;  //rotary encoder push
16const int CCW = 8; //rotary encoder counterclockwise
17const  int CW = 9;  //rotary encoder clockwise
18
19//Global Variables
20int ack = 0;
21int  RH_set = 35; //start value for setting
22int SET = 0;
23int Direction = 0;
24boolean  T_condition = true;
25boolean RH_condition = true;
26long previousMillis = 0;
27long  interval = 2000;
28
29void setup()
30{
31  pinMode(Fog, OUTPUT);
32  pinMode(Fan,  OUTPUT);
33  pinMode(OK, OUTPUT);
34  pinMode(CCW, OUTPUT);
35  pinMode(CW, OUTPUT);
36
37  digitalWrite(Fog, LOW);
38  digitalWrite(OK, HIGH);
39  digitalWrite(CCW, HIGH);
40  digitalWrite(CW, HIGH);
41
42  Serial.begin(9600);
43  dht.begin();
44  
45  // show start page on OLED display; delay for 1.5s
46  u8g.firstPage();
47  do
48  {
49    u8g.setFont(u8g_font_helvB14);
50    u8g.drawStr(10, 20, "Climate");
51    u8g.drawStr(10, 40, "Chamber");
52  } while (u8g.nextPage());
53
54  delay(1500);
55}
56
57void  loop()
58{
59  if (SET == 0)
60  {
61    float T = dht.readTemperature();
62    float RH = dht.readHumidity();
63    
64    // show setting menu on OLED display
65    u8g.firstPage();
66    do
67    {
68      u8g.setFont(u8g_font_helvB08);
69      u8g.drawStr(10, 20, "Set Humidity:");
70      u8g.setPrintPos(20, 40);
71      u8g.print(RH_set);
72      u8g.drawStr(40, 40, "%");
73    } while (u8g.nextPage());
74    delay(100);
75    
76    
77    while (RH_condition)
78    {
79      //  +5 when encoder is rotated clockwise; set upper-limit to 100
80      if (digitalRead(CW)  == LOW)
81      {
82        RH_set = RH_set + 5;
83        if (RH_set > 100)
84        {
85          RH_set = 100;
86        }
87        
88        // show  value changes on OLED display
89        u8g.firstPage();
90        do
91        {
92          u8g.setFont(u8g_font_helvB08);
93          u8g.drawStr(10, 20, "Set  Humidity:");
94          u8g.setPrintPos(20, 40);
95          u8g.print(RH_set);
96          u8g.drawStr(40, 40, "%");
97        } while (u8g.nextPage());
98        delay(100);
99      }
100      
101      // -5 when encoder is rotated counterclockwise; set lower-limit  to 30
102      if (digitalRead(CCW) == LOW)
103      {
104        RH_set = RH_set  - 5;
105        if (RH_set < 30)
106        {
107          RH_set = 30;
108        }
109        
110        // show value changes on OLED display
111        u8g.firstPage();
112        do
113        {
114          u8g.setFont(u8g_font_helvB08);
115          u8g.drawStr(10,  20, "Set Humidity:");
116          u8g.setPrintPos(20, 40);
117          u8g.print(RH_set);
118          u8g.drawStr(40, 40, "%");
119        } while (u8g.nextPage());
120        delay(200);
121      }
122      if (digitalRead(OK) == LOW)
123      {
124        delay(100);
125        RH_condition = false;
126      }
127    }
128    
129    // confirm setting  to don't repeat this process
130    SET = 1;
131  }
132  
133  // continously read  actual conditions via the DHT22 every 2 seconds:
134  //if the difference between  the current time and last time the DHT22        was read is bigger than the interval  at which you want it to be read      -> read DHT22
135  unsigned long currentMillis  = millis();
136  if (currentMillis - previousMillis > interval)
137  { 
138    //  save the last time you read the DHT22 
139    previousMillis = currentMillis;
140    
141    float RH = dht.readHumidity();
142    float T = dht.readTemperature();
143    
144    // show DHT22 reading on OLED display
145    u8g.firstPage();
146    do
147    {
148      float T = dht.readTemperature();
149      float RH = dht.readHumidity();
150      u8g.setFont(u8g_font_helvB08);
151      u8g.drawStr( 2, 20, "Temperature:");
152      u8g.setPrintPos(80, 20);
153      u8g.print(T);
154      u8g.drawStr( 110,  20, "*C");
155      u8g.drawStr( 3, 50, "Humidity:");
156      u8g.setPrintPos(80,  50);
157      u8g.print(RH);
158      u8g.drawStr( 112, 50, "%");
159    } while  (u8g.nextPage());
160    
161    //humidity control: 
162    //if humidity equal  to or above set point -> nebulisers stay off
163    if (RH  >= RH_set)
164    {
165      delay(3000);
166      if (RH >= RH_set)
167      {
168        digitalWrite(Fog,  LOW);
169        analogWrite(Fan, 180);
170      }
171    }
172    
173    //if  humidity below set point -> nebulisers turn on for 2s; 
174    if (RH < RH_set)
175    {
176      delay(3000);
177      if (RH < RH_set)
178      {
179        digitalWrite(Fog,  HIGH);
180        analogWrite(Fan, 180);
181        delay(2000);
182        digitalWrite(Fog,  LOW);
183      }
184    }
185  }
186}
187