Day 18: Weather monitoring

/*
  TCP-Server Climate with server send events
  Change SSID and PASSWORD.
*/

#include <NanoESP.h>
#include <NanoESP_HTTP.h>
#include <SoftwareSerial.h>
#include "Websites.h"

#include <math.h>

//#define SSID "YourSSID"
//#define PASSWORD "YourPassword"

#define LED_WLAN 13

#define TEMP A0
#define LIGHT A1
#define HUMIDITY A4
#define GND A5

#define DEBUG true

NanoESP nanoesp = NanoESP();
NanoESP_HTTP http = NanoESP_HTTP(nanoesp);

void setup() {
  Serial.begin(19200);
  nanoesp.init();

  //! Only if you want to change the ACCESPOINT configuration
  //nanoesp.configWifi(ACCESSPOINT, "NanoESP", "");
  
  //! Only if you use a new Network
  // nanoesp.configWifi(DUAL, SSID, PASSWORD);
    
  //Dual Mode
  nanoesp.configWifiMode(DUAL);
  //delay(1000);
  
  // Wait till Connected to WiFi
  if (nanoesp.wifiConnected())digitalWrite(LED_WLAN, HIGH); else Serial.println(F("Error WLAN Connect"));

  //Start TCP Server
   if (nanoesp.startTcpServer(80))    Serial.println(F("TCP Server Activ")); else   Serial.println(F("TCP Server Error"));
   
  //Print IP in Terminal
  Serial.println(nanoesp.getIp());
}

int streamId = -1;
byte errorCount; 

void loop() {
  String method, ressource, parameter;
  int id ;

  if (http.recvRequest(id, method, ressource, parameter)) {

    Serial.println("New Request from id :" + String(id) + ", method: " + method +  ", ressource: " + ressource +  " parameter: " + parameter);

    if (ressource == "/") {
      http.sendFromFlash(id, index, sizeof(index));
      nanoesp.closeConnection(id);
    }

    else if (ressource == "/eventclimate") {                   //new server send events connection
      if (http.sendStreamHeader(id)) {                         //send stream header as response
        streamId = id;                                         //this id belongs to the sse-client
        sendStreamData(streamId,"msg", "Connection established");   //send first message
      }
    }

    else {
      http.sendFromFlash(id, error404, sizeof(error404));
      nanoesp.closeConnection(id);
    }
  }

  if (streamId > -1) { //there is a stream client
    if (!sendStreamData(streamId, "hum", String(getRF()))) errorCount++; else errorCount = 0; //send server send event data
    if (!sendStreamData(streamId, "light", String(getLight()))) errorCount++;else errorCount = 0; //send server send event data
    if (!sendStreamData(streamId, "temp", String(getTemp()))) errorCount++;else errorCount = 0; //send server send event data

    if (errorCount > 6){ //client is disconnected if more than 6 transmissions were faulty
      nanoesp.closeConnection(streamId);
      streamId = -1;
      errorCount = 0;
    }
  }
  
}

boolean sendStreamData(int connectionId, String event, String data) {
  //Serial.println(String (connectionId) + " - "  + event + " - " + data);
  return nanoesp.sendData(connectionId, "event: " + event + "\n" +  "data: " + data + "\n\n");
}

int getRF() { //get Humidity, source: http://www.elektronik-labor.de/AVR/Rmessung.html#rx2
  long U, R;
  double F;

  pinMode(HUMIDITY, INPUT);       //  Ddrb.3 = 0      'Eingang
  digitalWrite(HUMIDITY, HIGH);   //  Portb.3 = 1     'Pullup ein
  U = analogRead(HUMIDITY);       //  U = Getadc(3)
  digitalWrite(HUMIDITY, LOW);    //  Portb.3 = 0     'Pullup Aus
  pinMode(HUMIDITY, OUTPUT);      //  Ddrb.3 = 1 'Nierohmig

  pinMode(GND, INPUT);            //  Ddrb.4 = 0      'Eingang
  digitalWrite(GND, HIGH);        //  Portb.4 = 1     'Pullup ein
  U += analogRead(GND);           //   U = U + Getadc(2)
  digitalWrite(GND, LOW);         //  Portb.4 = 0     'Pullup Aus
  pinMode(GND, OUTPUT);           //  Ddrb.4 = 1 'Nierohmig. entladen

  U = U / 2;
  R = 3500 * U;                 //'R=35k*(U/1023-U)
  U = 1023 - U;
  R = (U > 0) ? R / U : 999999;     //alternativ writing to: if(U>0) R = R/U; else R=999999;
  R = R - 450;                      //- interner Bahnwiderstand 0,45 k

  //Calculate Humidity
  F = R / 280;
  F = log(F);                                                //ln f !!!
  F = F * 8.9;
  F = 100 - F;
  F = round(F);

 // Serial.println(String(R) + "Ohm     " + String(F) + "%");
  //delay(500);
  return F;
}

double getTemp() {
  //Source: http://playground.arduino.cc/ComponentLib/Thermistor2
  double Temp;
  int RawADC = analogRead(TEMP);
  Temp = log(10000.0 * ((1024.0 / RawADC - 1)));
  //         =log(10000.0/(1024.0/RawADC-1)) // for pull-up configuration
  Temp = 1 / (0.001129148 + (0.000234125 + (0.0000000876741 * Temp * Temp )) * Temp );
  Temp = Temp - 273.15;            // Convert Kelvin to Celcius
  // Temp = (Temp * 9.0)/ 4.7 + 32.0; // Convert Celcius to Fahrenheit

  Temp = round(Temp*10);
  Temp = Temp/ 10;  
  return Temp;
}

int getLight() {
  int vLight = analogRead(LIGHT);
  return vLight;
}