This tutorial will explain how this project works and its code. It is based on the last project but this time we’ll having more control of the leds, temperature and relay.
Components:
- 1 Arduino
- 1 Ethernet Shield
- 1 BreadBoard
- 3 Leds
- 3 Resistances
- 1 Temperature sensor
In this project, we’re able to check the temperature in the room that the temperature sensor is located and write the temperature we want it to be, depending on the temperature we want and the real one, there’s a text saying if it is equal, too low or too high.
We simulate the Air conditioning with leds that turn on.
This sketch automatically refreshes when the light values change.
Here’s how it looks:
When the temperature chosen is the same as the actual one:
When the temperature chosen is lower than the actual one:
When the temperature chosen is higher than the actual one:
The sketch:
The code we used:
#include <String.h>
#include <SPI.h>
#include <Ethernet.h>
byte mac[] = { 0xDE, 0xAD, 0xBE, 0xEF, 0xFE, 0xED }; // mac address
byte ip[] = { 192, 168, 1, 25 }; // ip arduino internet in
byte subnet[] = { 255, 255, 255, 0 }; //subnet mask
EthernetServer server(80); //server port
int outPin = 9; // pin
int y1=0; // reference temperature
String readString; //string
boolean LEDON = false; // flag status
float vrif = 1.1; // for the temperature
void setup()
{
Ethernet.begin(mac, ip, subnet);
pinMode(outPin, OUTPUT);
analogReference(INTERNAL); //lowers the voltage reference
pinMode(8,OUTPUT); //cold
pinMode(10,OUTPUT); // hot
pinMode(7,OUTPUT); // rele
pinMode(0,INPUT);
Serial.begin(9600);
}
void loop()
{
char string[100];
int y=0;
long int light=0;
for(y=0;y<=100;y++) // put the string with 0
{
string[y]=0;
}
// Temperature:
float x=0, x2= 0;
float from_sv=0;
x = analogRead(5); // temperature
light= analogRead(0); // light
// TEMPERATURE
x2 += (95.0 * vrif * x) / 1024.0;
//LIGHT
light= light * 100 ;
light= light / 1023;
EthernetClient client = server.available();
if (client) {
boolean currentLineIsBlank = true;
while (client.connected()) {
if (client.available()) {
char c = client.read();
readString.concat(c);
//if HTTP request has ended
if (c == '\n' && currentLineIsBlank) {
String string = String(readString);
Serial.print(readString);
if(readString.indexOf("L=1") > 0) {// (L=1 or L=0 will be in the string)
digitalWrite(outPin, HIGH);
LEDON = true;
Serial.print("ON pin ");
Serial.println(outPin);
}
else
{
if(readString.indexOf("L=0") > 0){ // "<0" means "L=0" is there in the string
digitalWrite(outPin, LOW);
LEDON = false;
Serial.print("OFF pin ");
Serial.println(outPin);
}
if(readString.indexOf("T=") > 0) // "T" is defined in the html part
{
y1=0; // y1 is 0 again
for(int i=0;string[i]!= '\0';i++)
{
if(string[i]== 'T' && string[i+1]== '=')
{
Serial.println(string[i+2]); //prints what's next to the "="
switch(string[i+2])
{
case 48: y1+= 0; break; // y1 represents the value returned by the site
case 49: y1+=10; break;
case 50: y1+=20; break;
case 51: y1+=30; break;
case 52: y1+=40; break;
case 53: y1+=50; break;
case 54: y1+=60; break;
case 55: y1+=70; break;
case 56: y1+=80; break;
case 57: y1+=90; break;
}
Serial.println(y1);
switch(string[i+3])
{
case 48: y1+= 0; break;
case 49: y1+=1; break;
case 50: y1+=2; break;
case 51: y1+=3; break;
case 52: y1+=4; break;
case 53: y1+=5; break;
case 54: y1+=6; break;
case 55: y1+=7; break;
case 56: y1+=8; break;
case 57: y1+=9; break;
}
Serial.println(y1); // y1 converts, I mean, we get the input like 22 but arduino reads it as another number from ASCII, tyhis way we have to convert to a normal number again(ex: input: 22 -> represents 55 -> converts to 22 again and prints to the web page)
}
}
}
}
// WEB PAGE
client.println("HTTP/1.1 200 OK.....");
client.println("Content-Type: text/html");
client.println();
client.print("<html> <style> table ,th, dt{ border:1px solid black; border-collapse:collapse;}"); // creates the table and costumizes the border for the temperature
client.println("th, dt {padding:5px;}</style>"); // also border costumization
client.println("<table><tr><th>Led status:</th>");
client.print("<th>");
if (LEDON) {
client.println("<span style='color:green; font-weight:bold;'>ON</span></font>");
}
else
{
client.println("<span style='color:grey; font-weight:bold;'>OFF</span></font>");
}
client.print("</th>");
if(y1!=0)
{
client.println(" <th rowspan=""4"">");
if((int)x2 == y1)
{
client.println("Temperature OK!!!</th>");
digitalWrite(7,LOW);
digitalWrite(8,LOW);
digitalWrite(10,LOW);
LEDON=false;
}
if(x2>y1)
{
client.println("Turn Heater ON!!</th>");
digitalWrite(7,HIGH);
digitalWrite(10,HIGH);
digitalWrite(8,LOW);
LEDON=true;
}
if(x2<y1)
{
client.println("Turn Air condicioning ON!!</th>");
digitalWrite(7,HIGH);
digitalWrite(8,HIGH);
digitalWrite(10,LOW);
LEDON=true;
}
}
client.print("<tr><th>Reference Temperature wanted </th>"); client.print("<th> <form action="" method=""get""><input type=""text"" name=""T"" value=""Insert value""><input type=""submit"" value=""check""><?phpif(!isset($_GET['temp']))$var_1 = "";else$var_1 = $_GET['temp'];$_SESSION['data'] = $var_1;?></th>");
client.print("<tr><th>Reference Temperature is set to</th><th>"); client.print(y1); client.print("</th><tr>");
client.println("<?PHP echo $_SESSION['data'];?>");
client.println("<tr><th>Temperature of the room</th>");
client.print("<th>"); client.print(x2); client.println("</th>");
client.print("<tr><th>Light level</th><th>"); client.print(light); client.print("% </th><tr></table>");
client.println("</body></html>");
readString="";
client.stop();
}
}
}
}
}
23 of July 2014
Alexandre Leitao
Gonçalo Neto
