Arduino Weather Shield Hookup Guide V12
Example Firmware - Weather Station
For the more adventurous, check out the Weather_Shield_Weather_Station_V12.ino
sketch. This code demonstrates shield's capabilities to collect weather data, when a weather meter kit is connected:
/* Weather Shield Example By: Nathan Seidle SparkFun Electronics Date: November 16th, 2013 License: This code is public domain but you buy me a beer if you use this and we meet someday (Beerware license). Much of this is based on Mike Grusin's USB Weather Board code: https://www.sparkfun.com/products/10586 This is a more advanced example of how to utilize every aspect of the weather shield. See the basic example if you're just getting started. This code reads all the various sensors (wind speed, direction, rain gauge, humidity, pressure, light, batt_lvl) and reports it over the serial comm port. This can be easily routed to a datalogger (such as OpenLog) or a wireless transmitter (such as Electric Imp). Measurements are reported once a second but windspeed and rain gauge are tied to interrupts that are calculated at each report. This example code assumes the GPS module is not used. Updated by Joel Bartlett 03/02/2017 Removed HTU21D code and replaced with Si7021 Updated be Wes Furuya 06/19/2023 Implemented "Weather Meter" Arduino library */ //Hardware pin definitions //-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-= // digital I/O pins const byte WSPEED = 3; const byte RAIN = 2; const byte STAT1 = 7; const byte STAT2 = 8; // analog I/O pins const byte REFERENCE_3V3 = A3; const byte LIGHT = A1; const byte BATT = A2; const byte WDIR = A0; //-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-= //Global Variables //-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-= long lastSecond; //The millis counter to see when a second rolls by float humidity = 0; // [%] float tempf = 0; // [temperature F] //float baromin = 30.03;// [barom in] - It's hard to calculate baromin locally, do this in the agent float pressure = 0; float wind_dir = 0; // [degrees (Cardinal)] float wind_speed = 0; // [kph] float rain = 0; // [mm] float batt_lvl = 11.8; //[analog value from 0 to 1023] float light_lvl = 455; //[analog value from 0 to 1023] //-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-= MPL3115A2 myPressure; //Create an instance of the pressure sensor Weather myHumidity; //Create an instance of the humidity sensor SFEWeatherMeterKit myweatherMeterKit(WDIR, WSPEED, RAIN); // Create an instance of the weather meter kit void setup() { Serial.begin(115200); Serial.println("Weather Shield Example"); pinMode(STAT1, OUTPUT); //Status LED Blue pinMode(STAT2, OUTPUT); //Status LED Green // pinMode(WSPEED, INPUT_PULLUP); // input from wind meters windspeed sensor // pinMode(RAIN, INPUT_PULLUP); // input from wind meters rain gauge sensor pinMode(REFERENCE_3V3, INPUT); pinMode(LIGHT, INPUT); //Configure the pressure sensor myPressure.begin(); // Get sensor online myPressure.setModeBarometer(); // Measure pressure in Pascals from 20 to 110 kPa myPressure.setOversampleRate(7); // Set Oversample to the recommended 128 myPressure.enableEventFlags(); // Enable all three pressure and temp event flags //Configure the humidity sensor myHumidity.begin(); // The weather meter kit library assumes a 12-bit ADC // Configuring a 10-bit ADC resolution for the ATmega328 (RedBoard/Uno) myweatherMeterKit.setADCResolutionBits(10); // Begin weather meter kit myweatherMeterKit.begin(); lastSecond = millis(); // // attach external interrupt pins to IRQ functions // attachInterrupt(0, rainIRQ, FALLING); // attachInterrupt(1, wspeedIRQ, FALLING); // // turn on interrupts // interrupts(); Serial.println("Weather Shield online!"); } void loop() { //Keep track of which minute it is if (millis() - lastSecond >= 1000) { digitalWrite(STAT1, HIGH); //Blink stat LED lastSecond += 1000; //Report all readings every second printWeather(); } digitalWrite(STAT1, LOW); //Turn off stat LED delay(100); } //Calculates each of the variables that wunderground is expecting void calcWeather() { //Calc temp/humidity from Si7021 sensor humidity = myHumidity.getRH(); tempf = myHumidity.readTempF(); //Weather Meter Kit //Calc Wind wind_dir = myweatherMeterKit.getWindDirection(); wind_speed = myweatherMeterKit.getWindSpeed(); //Calc Rain rain = myweatherMeterKit.getTotalRainfall(); //Calc pressure from MPL3115A2 pressure = myPressure.readPressure(); //Calc light level light_lvl = get_light_level(); //Calc battery level batt_lvl = get_battery_level(); } //Returns the voltage of the light sensor based on the 3.3V rail //This allows us to ignore what VCC might be (an Arduino plugged into USB has VCC of 4.5 to 5.2V) float get_light_level() { float operatingVoltage = analogRead(REFERENCE_3V3); float lightSensor = analogRead(LIGHT); operatingVoltage = 3.3 / operatingVoltage; //The reference voltage is 3.3V lightSensor = operatingVoltage * lightSensor; return (lightSensor); } //Returns the voltage of the raw pin based on the 3.3V rail //This allows us to ignore what VCC might be (an Arduino plugged into USB has VCC of 4.5 to 5.2V) //Battery level is connected to the RAW pin on Arduino and is fed through two 5% resistors: //3.9K on the high side (R1), and 1K on the low side (R2) float get_battery_level() { float operatingVoltage = analogRead(REFERENCE_3V3); float rawVoltage = analogRead(BATT); operatingVoltage = 3.30 / operatingVoltage; //The reference voltage is 3.3V rawVoltage = operatingVoltage * rawVoltage; //Convert the 0 to 1023 int to actual voltage on BATT pin rawVoltage *= 4.90; //(3.9k+1k)/1k - multiple BATT voltage by the voltage divider to get actual system voltage return (rawVoltage); } //Prints the various variables directly to the port //I don't like the way this function is written but Arduino doesn't support floats under sprintf void printWeather() { calcWeather(); //Go calc all the various sensors Serial.println(); Serial.print("humidity="); Serial.print(humidity, 1); Serial.print(" %RH, tempf="); Serial.print(tempf, 1); Serial.print(" F, pressure="); Serial.print(pressure, 2); Serial.print(" Pa, wind direction= "); Serial.print(wind_dir, 1); Serial.print(" deg, wind speed= "); Serial.print(wind_speed, 1); Serial.print(" kph, total rain= "); Serial.print(rain, 1); Serial.print(" mm, batt_lvl="); Serial.print(batt_lvl, 2); Serial.print(" V, light_lvl="); Serial.print(light_lvl, 2); Serial.print(","); Serial.println(" }
Upload the sketch onto your board and open the serial monitor at 115200 bps. You should see output similar to the following:
Click the image for a closer look.