Ethernet-temp-humidity

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ETHERNET WEB SERVER SHOWING TEMPERATURE AND HUMIDITY


The example here combines the DHT11 Temperature sensor and the Ethernet Shield or Ethernet Brick to provide a Web server that displays Temperature, Humidity and Dew Point. NOTE: this uses Arduino Software IDE V 1.03 (earlier MAY work)

The Ethernet interface uses pins 10,11,12,13
The DHT11 sensor uses Pin 2 (You can pick other pins)
See info on the DHT11 HERE:

See [/Ethernet the "ethernet" page] first, to get your interface working with a simple web server.


Here is a .ZIP file available with the DHT11 files for easier installation:
[/file/view/DHT11.zip/390039522/DHT11.zip DHT11.zip]
[/file/view/DHT11.zip/390039522/DHT11.zip DHT11.zip]
  • [/file/detail/DHT11.zip Details]
  • [/file/view/DHT11.zip/390039522/DHT11.zip Download]
  • 3 KB

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Here's what the screen on the browser will look like:


Temperature (C): 23.0
Temperature (F): 73.4
Humidity (%): 21
Temperature (K): 296.1
Dew Point (C): -0.48
Dew PointFast (C): -0.51


It will refresh itself every 5 seconds as defined in the Sketch.

Cut and paste this into an Arduino IDE window:

/* YourDuino Ethernet Temperature/humidity Web Server
 Reads a DHT11 Sensor
 Outputs a web page with Temperature and Humidity
 terry@yourduino.com 
 
 Circuit:
 * Ethernet shield attached to pins 10, 11, 12, 13
 * DHT11 Sensor connected to Pin 2
 
 Based on code by David A. Mellis & Tom Igoe
 
 */
/*-----( Import needed libraries )-----*/
#include <SPI.h>
#include <Ethernet.h>
#include <dht11.h>
#include <Wire.h>

/*-----( Declare Constants and Pin Numbers )-----*/
#define DHT11PIN 2  // The Temperature/Humidity sensor

// Enter a MAC address and IP address for your controller below.
// The IP address will be dependent on your local network:
byte mac[] = {
  0xDE, 0xAD, 0xBE, 0xEF, 0xFE, 0xED };

/*-----( Declare objects )-----*/
IPAddress ip(192,168,1, 120);

// Initialize the Ethernet server library
// with the IP address and port you want to use 
// (port 80 is default for HTTP):
EthernetServer server(80);

dht11 DHT11;  //The Sensor Object
/*-----( Declare Variables )-----*/



void setup()   /****** SETUP: RUNS ONCE ******/
{
  // Open serial communications and wait for port to open:
  Serial.begin(9600);
  while (!Serial) {
    ; // wait for serial port to connect. Needed for Leonardo only
  }


  // start the Ethernet connection and the server:
  Ethernet.begin(mac, ip);
  server.begin();
  Serial.print("server is at ");
  Serial.println(Ethernet.localIP());
}//--(end setup )---


void loop()   /*----( LOOP: RUNS OVER AND OVER AGAIN )----*/
{
  // listen for incoming clients
  EthernetClient client = server.available();
  if (client) {
    Serial.println("new client");
    // an http request ends with a blank line
    boolean currentLineIsBlank = true;
    while (client.connected()) {
      if (client.available()) {
        char c = client.read();
        Serial.write(c);
        // if you've gotten to the end of the line (received a newline
        // character) and the line is blank, the http request has ended,
        // so you can send a reply
        if (c == '\n' && currentLineIsBlank) {
          // send a standard http response header
          client.println("HTTP/1.1 200 OK");
          client.println("Content-Type: text/html");
          client.println("Connnection: close");
          client.println();
          client.println("<!DOCTYPE HTML>");
          client.println("<html>");
          // add a meta refresh tag, so the browser pulls again every 5 seconds:
          client.println("<meta http-equiv=\"refresh\" content=\"5\">");
          client.print("Hi Mary Alice!");
          client.println("
"
); /*----(Get sensor reading, calculate and print results )-----------------*/ int chk = DHT11.read(DHT11PIN); Serial.print("Read sensor: "); switch (chk) { case 0: Serial.println("OK"); break; case -1: Serial.println("Checksum error"); break; case -2: Serial.println("Time out error"); break; default: Serial.println("Unknown error"); break; } client.print("Temperature (C): "); client.println((float)DHT11.temperature, 1); client.println("
"
); client.print("Temperature (F): "); client.println(Fahrenheit(DHT11.temperature), 1); client.println("
"
); client.print("Humidity (%): "); client.println((float)DHT11.humidity, 0); client.println("
"
); client.print("Temperature (K): "); client.println(Kelvin(DHT11.temperature), 1); client.println("
"
); client.print("Dew Point (C): "); client.println(dewPoint(DHT11.temperature, DHT11.humidity)); client.println("
"
); client.print("Dew PointFast (C): "); client.println(dewPointFast(DHT11.temperature, DHT11.humidity)); client.println("
"
); /*--------( End Sensor Read )--------------------------------*/ client.println("</html>"); break; } if (c == '\n') { // you're starting a new line currentLineIsBlank = true; } else if (c != '\r') { // you've gotten a character on the current line currentLineIsBlank = false; } } } // give the web browser time to receive the data delay(1); // close the connection: client.stop(); Serial.println("client disonnected"); } } // END Loop /*-----( Declare User-written Functions )-----*/ // //Celsius to Fahrenheit conversion double Fahrenheit(double celsius) { return 1.8 * celsius + 32; } //Celsius to Kelvin conversion double Kelvin(double celsius) { return celsius + 273.15; } // dewPoint function NOAA // reference: http://wahiduddin.net/calc/density_algorithms.htm double dewPoint(double celsius, double humidity) { double A0= 373.15/(273.15 + celsius); double SUM = -7.90298 * (A0-1); SUM += 5.02808 * log10(A0); SUM += -1.3816e-7 * (pow(10, (11.344*(1-1/A0)))-1) ; SUM += 8.1328e-3 * (pow(10,(-3.49149*(A0-1)))-1) ; SUM += log10(1013.246); double VP = pow(10, SUM-3) * humidity; double T = log(VP/0.61078); // temp var return (241.88 * T) / (17.558-T); } // delta max = 0.6544 wrt dewPoint() // 5x faster than dewPoint() // reference: http://en.wikipedia.org/wiki/Dew_point double dewPointFast(double celsius, double humidity) { double a = 17.271; double b = 237.7; double temp = (a * celsius) / (b + celsius) + log(humidity/100); double Td = (b * temp) / (a - temp); return Td; }
/* ( THE END ) */