Arduino Weather Station Code

weather_shield.ino

+#include <SoftwareSerial.h>
+#include <Wire.h> //I2C needed for sensors
+#include <MQUnifiedsensor.h>
+#include "SparkFunMPL3115A2.h" //Pressure sensor 
+#include "SparkFun_Si7021_Breakout_Library.h" //Humidity sensor 
+
+#define placa "Arduino UNO"
+#define Voltage_Resolution 5
+#define pin A0 //Analog input 0
+#define type "MQ-135" 
+#define ADC_Bit_Resolution 10 
+#define RatioMQ135CleanAir 3.6//RS / R0 = 3.6 ppm  
+
+MPL3115A2 myPressure; 
+Weather myHumidity;
+SoftwareSerial BTSerial(10, 11); // RX | TX
+
+const byte STAT_BLUE = 7;
+const byte STAT_GREEN = 8;
+
+const byte REFERENCE_3V3 = A3;
+const byte LIGHT = A1;
+const byte BATT = A2;
+
+MQUnifiedsensor MQ135(placa, Voltage_Resolution, ADC_Bit_Resolution, pin, type);
+
+long lastSecond; 
+char data[26];
+const int ledWarning  =  8;     //use digital I/O pin 8
+const int ledGood  =  9;     //use digital I/O pin 9
+
+void setup()
+{
+  Serial.begin(9600);
+  BTSerial.begin(9600);
+  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
+  pinMode(ledGood,OUTPUT);   
+  pinMode(ledWarning,OUTPUT);
+  
+  //Set math model to calculate the PPM concentration and the value of constants 
+  MQ135.setRegressionMethod(1); //_PPM =  a*ratio^b
+  MQ135.init(); 
+  
+  Serial.print("Calibrating please wait.");
+  float calcR0 = 0;
+  for(int i = 1; i<=10; i ++)
+  {
+    MQ135.update(); // Update data, the arduino will be read the voltage on the analog pin
+    calcR0 += MQ135.calibrate(RatioMQ135CleanAir);
+    Serial.print(".");
+  }
+  
+  MQ135.setR0(calcR0/10);
+  Serial.println("  done!.");
+  
+  if(isinf(calcR0)) {Serial.println("Warning: Conection issue founded, R0 is infite (Open circuit detected) please check your wiring and supply"); while(1);}
+  if(calcR0 == 0){Serial.println("Warning: Conection issue founded, R0 is zero (Analog pin with short circuit to ground) please check your wiring and supply"); while(1);}
+  
+  digitalWrite(ledGood,HIGH);   
+  myHumidity.begin();
+  lastSecond = millis();
+  Serial.println("Weather Shield online!");
+}
+
+void loop()
+{
+    float humidity = myHumidity.getRH();//Check Humidity Sensor
+    MQ135.update();
+
+    if (humidity == 998) //Humidty sensor failed to respond
+    {
+      Serial.println("I2C communication to sensors is not working. Check solder connections.");
+
+      //Try re-initializing the I2C comm and the sensors
+      myPressure.begin(); 
+      myPressure.setModeBarometer();
+      myPressure.setOversampleRate(7);
+      myPressure.enableEventFlags();
+      myHumidity.begin();
+    }
+    else
+    {
+      //Check Humidity Sensor
+      String dataH = "Humidity: " + String(humidity) + "%";
+      dataH.toCharArray(data,26);
+      BTSerial.write(data);
+      Serial.print(data);
+
+      //Check Temperature Sensor
+      float temp_h = (myHumidity.getTempF() - 32) * 5/9;
+      String dataT = "Temp: " + String(temp_h) + "C";
+      dataT.toCharArray(data,26);
+      BTSerial.write(data);
+      Serial.print(data);
+
+      //Check Pressure Sensor
+      float pressure = myPressure.readPressure();
+      String dataP = "Pressure: " + String(pressure) + "Pa";
+      dataP.toCharArray(data,26);
+      BTSerial.write(data);
+      Serial.print(data);
+
+      //Check light sensor
+      float light_lvl = get_light_level();
+      String dataL = ("Light: " + String(light_lvl) + "V");
+      dataL.toCharArray(data,26);
+      BTSerial.write(data);
+      Serial.print(data);
+      delay(100);
+
+      //Check CO Sensor
+      float CO = get_CO();
+      String dataCO = ("CO1: " + String(CO) + "PPM");
+      dataCO.toCharArray(data,26);
+      Serial.write(data);
+      delay(100);
+
+      //Check Alcohol Sensor
+      float Alcohol = get_Alcohol();
+      String dataAlc = ("Alcohol: " + String(Alcohol) + "PPM");
+      dataAlc.toCharArray(data,26);
+      Serial.write(data);
+      delay(100);
+
+    }
+    
+    checkLevels(CO);
+    delay(10000);
+}
+
+void checkLevels(float CO)
+{
+  if (CO > 10){
+    digitalWrite(ledGood,LOW);   //Green LED off
+    digitalWrite(ledWarning,HIGH);   //Red LED on
+  }else{
+    digitalWrite(ledGood,HIGH);  //Green LED on
+    digitalWrite(ledWarning,LOW);   //Red LED off
+  }
+}
+
+float get_CO()
+{
+  MQ135.setA(605.18); MQ135.setB(-3.937);
+  return(MQ135.readSensor());
+}
+
+
+float get_Alcohol()
+{
+  MQ135.setA(77.255); MQ135.setB(-3.18);
+  return(MQ135.readSensor());
+}
+
+
+float get_CO2()
+{
+  MQ135.setA(110.47); MQ135.setB(-2.862);
+  return(MQ135.readSensor());
+}
+
+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);
+}
+
+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);
+}