Ethernet-temp-humidity
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Here is a .ZIP file available with the DHT11 files for easier installation:
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
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 ) */