Weather Station Web Server (Part 9)
The software sketch shown below turns the weather station into a basic web server. This allows you to connect to the station using a web browser of your choice. Using the static IP address assigned to EtherTen board we enter this as this url in the browser. In this case we enter http://192.168.1.45 into the browser. If all is good we should get html returned to our browser that shows the current value for each of the sensors in the weather station.This will only work on your internal network. You cannot access it via the internet as it uses a private IP address range. To enable access to the weather station from the Internet we would need to setup port forwarding on the router that connects the internal network to the Internet.
Software
With the sketch we are going to use some of the functionality we used in previous weather station sketches. Instead of outputing the data to the serial console we are going to listen for browser clients connecting to the weather station via the network cable. We setup a webserver to listen on port 80 for ip address 192.168.1.45.
In the software sketch we need to create a server and setup listening on port 80. To do this we need to specify a MAC and IP address. This is defined in lines 42 to 45. The MAC addess that was used, was one we got off an old modem that is no longer in use. Any item of network equipment would normally have a MAC address on a label attached to the gear. The internal network we use has the private IP address range of 192.168.1.X. We assigned host address of 45 to the weather station to get the IP address of 192.168.1.45
In the Setup function we initalise the sensors, timer and start the ethernet server. The timer we use is set to trigger every 0.5 seconds. We use this to get the 2.5 second sample period for the wind speed calcualtion. This is all done through the interrupt handler routines.
The main loop is where all of the action happens. We read the DS18B20 and BME280 sensors if required. From line 96 to 110 we update the min and max temp values. We also check if any rain has fallen and update the totals if needed.
From line 112 to 178 we listen for any browser clients connecting to the weather station web server. If a client is detected then we return the html code that displays the values from each of the sensors. Prior to sending the html data we turn on the TX LED (line 126). Once we have sent the data we turn off the TX LED (line 161).
In line 135 we have inserted some inline styling to make the text larger on the web page. This is for visual appearance only.
Software Sketch
Arduino Weather Station Basic Web Server Sketch(Download)
| 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 | #include <SPI.h> #include <Ethernet.h> #include “TimerOne.h” #include <math.h> #include “cactus_io_DS18B20.h” #include “cactus_io_BME280_I2C.h” #define Bucket_Size 0.01 // bucket size to trigger tip count #define RG11_Pin 3 // digital pin RG11 connected to #define TX_Pin 8 // used to indicate web data tx #define DS18B20_Pin 9 // DS18B20 Signal pin on digital 9 #define WindSensor_Pin (2) // digital pin for wind speed sensor #define WindVane_Pin (A2) // analog pin for wind direction sensor #define VaneOffset 0 // define the offset for caclulating wind direction volatile unsigned long tipCount; // rain bucket tip counter used in interrupt routine volatile unsigned long contactTime; // timer to manage any rain contact bounce in interrupt routine volatile unsigned int timerCount; // used to count ticks for 2.5sec timer count volatile unsigned long rotations; // cup rotation counter for wind speed calcs volatile unsigned long contactBounceTime; // timer to avoid contact bounce in wind speed sensor long lastTipcount; // keep track of bucket tips float totalRainfall; // total amount of rainfall detected volatile float windSpeed; int vaneValue; // raw analog value from wind vane int vaneDirection; // translated 0 – 360 wind direction int calDirection; // calibrated direction after offset applied int lastDirValue; // last recorded direction value float minTemp; // keep track of minimum recorded temp float maxTemp; // keep track of maximum recorded temp // Create DS18B20, BME280 object DS18B20 ds(DS18B20_Pin); // on digital pin 9 BME280_I2C bme; // I2C using address 0x77 // Here we setup the web server. We are using a static ip address and a mac address byte mac[] = { 0xDE, 0xAD, 0xBE, 0xEF, 0xFE, 0xED }; IPAddress ip(192, 168, 1, 45); EthernetServer server(80); // create a server listing on 192.168.1.45 port 80 void setup() { // setup rain sensor values lastTipcount = 0; tipCount = 0; totalRainfall = 0; // setup anemometer values lastDirValue = 0; rotations = 0; // setup timer values timerCount = 0; ds.readSensor(); minTemp = ds.getTemperature_C(); maxTemp = ds.getTemperature_C(); // disable the SD card by switching pin 4 High pinMode(4, OUTPUT); digitalWrite(4, HIGH); // start the Ethernet connection and server Ethernet.begin(mac, ip); server.begin(); if (!bme.begin()) { // Serial.println(“Could not find BME280 sensor, check wiring!”); while (1); } pinMode(TX_Pin, OUTPUT); pinMode(RG11_Pin, INPUT); pinMode(WindSensor_Pin, INPUT); attachInterrupt(digitalPinToInterrupt(RG11_Pin), isr_rg, FALLING); attachInterrupt(digitalPinToInterrupt(WindSensor_Pin), isr_rotation, FALLING); // setup the timer for 0.5 second Timer1.initialize(500000); Timer1.attachInterrupt(isr_timer); sei();// Enable Interrupts } void loop() { ds.readSensor(); bme.readSensor(); // update min and max temp values if(ds.getTemperature_C() < minTemp) { minTemp = ds.getTemperature_C(); } if(ds.getTemperature_C() > maxTemp) { maxTemp = ds.getTemperature_C(); } // update rainfall total if required if(tipCount != lastTipcount) { cli(); // disable interrupts lastTipcount = tipCount; totalRainfall = tipCount * Bucket_Size; sei(); // enable interrupts } // listen for incoming clients EthernetClient client = server.available(); if (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 digitalWrite(TX_Pin,HIGH); client.println(“HTTP/1.1 200 OK”); client.println(“Content-Type: text/html”); client.println(“Connection: close”); // connection closed completion of response client.println(“Refresh: 10”); // refresh the page automatically every 5 sec client.println(); client.println(“<!DOCTYPE HTML>”); client.println(“<html><body>”); digitalWrite(TX_Pin,HIGH); // Turn the TX LED on client.print(“<span style=\”font-size: 26px\”;><br> Temperature is “); client.print(ds.getTemperature_C()); client.println(” °C<br>”); client.print(“%<br> Humidity is “); client.print(bme.getHumidity()); client.println(” %<br>”); client.print(“%<br> Pressure is “); client.print(bme.getPressure_MB()); client.println(” mb%<br>”); client.print(“%<br> Wind Speed is “); client.print(windSpeed); client.println(” mph<br>”); getWindDirection(); client.print(“%<br> Direction is “); client.print(calDirection); client.println(” °<br>”); client.print(“%<br> Rainfall is “); client.print(totalRainfall); client.println(” mm<br>”); client.print(“%<br> Minimum Temp “); client.print(minTemp); client.println(” °C<br>”); client.print(“%<br> Maximum Temp “); client.print(maxTemp); client.println(” °C</span>”); client.println(“</body></html>”); digitalWrite(TX_Pin,LOW); // Turn the TX LED off 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(); } // Interrupt handler routine for timer interrupt void isr_timer() { timerCount++; if(timerCount == 5) { // convert to mp/h using the formula V=P(2.25/T) // V = P(2.25/2.5) = P * 0.9 windSpeed = rotations * 0.9; rotations = 0; timerCount = 0; } } // Interrupt handler routine that is triggered when the rg-11 detects rain void isr_rg() { if((millis() – contactTime) > 15 ) { // debounce of sensor signal tipCount++; totalRainfall = tipCount * Bucket_Size; contactTime = millis(); } } // Interrupt handler routine to increment the rotation count for wind speed void isr_rotation() { if((millis() – contactBounceTime) > 15 ) { // debounce the switch contact rotations++; contactBounceTime = millis(); } } // Get Wind Direction void getWindDirection() { vaneValue = analogRead(WindVane_Pin); vaneDirection = map(vaneValue, 0, 1023, 0, 360); calDirection = vaneDirection + VaneOffset; if(calDirection > 360) calDirection = calDirection – 360; if(calDirection > 360) calDirection = calDirection – 360; } |
Web Results
Fire up your favourite browser and enter into the url http://192.1681.145 (or alternate ip to suite your local network). If all is well then you should see something like this appear in the browser.
You can change what is sent from the weather station by modifying the html code in the sketch. If you want to display the wind speed in knots or km/hr you can create a function that does the conversion prior to sending to the browser.
Coming Up Next …
We create a more advanced web server that is accessible from the Internet.