Real Time Water Quality Monitoring System in The Wild

//include libraries
#include "rpcWiFi.h" //Wi-Fi library 
#include "DHT.h" //DHT library
#include "TFT_eSPI.h" //TFT LCD library 
#include "Free_Fonts.h" //free fonts library 
#include "SGP30.h" // coSensor

TFT_eSPI tft; //initialize TFT LCD
TFT_eSprite spr = TFT_eSprite(&tft); //initialize sprite buffer


#define DHTPIN 0 //define Signal Pin of DHT
#define DHTTYPE DHT11 //define DHT Sensor Type
DHT dht(DHTPIN, DHTTYPE); //initialize DHT sensor
#define DHTPIN 1 //define Signal Pin of DHT
#define SGPTYPE SGP30 //define sgp Sensor Type
SGP30 sgp(DHTPIN, DHTTYPE); //initialize sgp sensor
 
const char* ssid = "*****"; //Wi-Fi name    
const char* password =  "******"; //Wi-Fi password 


const char* serverName = "api.thingspeak.com"; //Domain Name for HTTP POST Request
String apiKey = "********"; //"Write API Key" from ThingSpeak

// Use WiFiClient class to create TCP connections
WiFiClient client;
 
void setup() {
  Serial.begin(115200); //start serial communication
  while (!Serial); //wait for Serial to be ready
  delay(100);
 
  WiFi.mode(WIFI_STA); //set WiFi to station mode 
  WiFi.disconnect(); //disconnect from an AP if it was previously connected
 
  Serial.println("Connecting to WiFi.."); //print string 
  WiFi.begin(ssid, password); //connect to Wi-Fi network
 
  // attempt to connect to Wi-Fi network:
  while (WiFi.status() != WL_CONNECTED) {
      Serial.print(".");
      // wait 1 second for re-trying
      delay(1000);
  }
    
  Serial.print("Connected to ");
  Serial.println(ssid); //print Wi-Fi name 
  Serial.print("IP Address: ");
  Serial.println(WiFi.localIP()); //print Wio Terminal's IP address
  Serial.println(""); //print empty line

  sgp.begin(); //Start DHT sensor
  
void loop() {
  Serial.print("Connecting to ");
  Serial.println(serverName); //print server IP address

  //check whether Wio Terminal is connected to server
  if (!client.connect(serverName, 80)) {  //80 is default port of HTTP
      Serial.println("Connection failed!");
  } else {
      Serial.println("Connected to server!");
      int t = dht.readTemperature(); //Assign variable to store temperature
  int h = dht.readHumidity(); //Assign variable to store humidity
  int c = SGP30.readCarbondioxide();

  //data needed to send along with API key
  String postStr = apiKey;
  postStr +="&field1=";
  postStr += String(t);
  postStr += "&field2=";
  postStr += String(h);
  postStr += "&field3=";
  postStr += String(c);
  postStr += "\r\n\r\n";

  //make an HTTP POST request
  client.print("POST /update HTTP/1.1\n");
  client.print("Host: api.thingspeak.com\n");
  client.print("Connection: close\n");
  client.print("X-THINGSPEAKAPIKEY: "+apiKey+"\n");
  client.print("Content-Type: application/x-www-form-urlencoded\n");
  client.print("Content-Length: ");
  client.print(postStr.length());
  client.print("\n\n");
  client.print(postStr);

  //display sensor data on serial monitor 
  Serial.print("temperature: "); //print string
  Serial.println(t); //print data stored in t
  Serial.print("Humidity:");
   Serial.println(h);
  Serial.print("Carbondioxide:");
  Serial.println(c);
                             
  Serial.println("Sent to Thingspeak.");

      
  //sprite buffer for temperature
  spr.createSprite(55, 40); //create buffer
  spr.fillSprite(TFT_BLACK); //fill background color of buffer
  spr.setFreeFont(FMB24); //set font type 
  spr.setTextColor(TFT_WHITE); //set text color
  spr.drawNumber(t, 0, 0); //display number 
  spr.pushSprite(200, 70); //push to LCD 
  spr.deleteSprite(); //clear buffer

  //sprite buffer for humidity 
  spr.createSprite(55, 40);
  spr.fillSprite(TFT_BLACK);
  spr.setFreeFont(FMB24);
  spr.setTextColor(TFT_WHITE);
  spr.drawNumber(h, 0, 0); 
  spr.pushSprite(155, 170);
  spr.deleteSprite();
  
  //sprite buffer for carbondioxide 
  spr.createSprite(55, 40);
  spr.fillSprite(TFT_BLACK);
  spr.setFreeFont(FMB24);
  spr.setTextColor(TFT_WHITE);
  spr.drawNumber(h, 0, 0); 
  spr.pushSprite(145, 180);
  spr.deleteSprite();
  
  }
  
  client.stop(); //disconnect from server
  //wait 10 seconds to send the next POST request
  Serial.println("Waiting...");
  delay(10000);
}