Smart Plant Watering System Using ThingSpeak

//NextPCB #include <ESP8266WiFi.h> //defines#define SSID_REDE     " " #define SENHA_REDE    "  " #define INTERVALO_ENVIO_THINGSPEAK  30000  //constants and global variableschar EnderecoAPIThingSpeak[] = "api.thingspeak.com";String ChaveEscritaThingSpeak = "KGFP6X4JQTJZFIAP";long lastConnectionTime; WiFiClient client; //prototypesvoid EnviaInformacoesThingspeak(String StringDados);void FazConexaoWiFi(void);float FazLeituraUmidade(void);/* * Implementations *///Function: sends information to ThingSpeak//Parameters: String with the information to be sent//Return: nonevoid EnviaInformacoesThingspeak(String StringDados){    if (client.connect(EnderecoAPIThingSpeak, 80))    {                 //makes the HTTP request to ThingSpeak        client.print("POST /update HTTP/1.1\n");        client.print("Host: api.thingspeak.com\n");        client.print("Connection: close\n");        client.print("X-THINGSPEAKAPIKEY: "+ChaveEscritaThingSpeak+"\n");        client.print("Content-Type: application/x-www-form-urlencoded\n");        client.print("Content-Length: ");        client.print(StringDados.length());        client.print("\n\n");        client.print(StringDados);           lastConnectionTime = millis();        Serial.println("- Information sent to ThingSpeak!");     }   } //Function: makes the WiFi connection//Parameters: none//Return: nonevoid FazConexaoWiFi(void){    client.stop();    Serial.println("Connecting to the WiFi network...");    Serial.println();      delay(1000);    WiFi.begin(SSID_REDE, SENHA_REDE);     while (WiFi.status() != WL_CONNECTED)     {        delay(500);        Serial.print(".");    }     Serial.println("");    Serial.println("WiFi connected successfully!");      Serial.println("IP obtained: ");    Serial.println(WiFi.localIP());     delay(1000);} float FazLeituraUmidade(void){    int ValorADC;    float UmidadePercentual;      ValorADC = analogRead(0);   //978 -> 3.3V     Serial.print("[ADC Reading] ");     Serial.println(ValorADC);           UmidadePercentual = 100 * ((978-(float)ValorADC) / 978);     Serial.print("[Percentage Humidity] ");     Serial.print(UmidadePercentual);     Serial.println("%");      return UmidadePercentual;}void setup(){      Serial.begin(9600);    lastConnectionTime = 0;     FazConexaoWiFi();    Serial.println("Plant IoT with ESP8266 NodeMCU");} //main loopvoid loop(){    float UmidadePercentualLida;    int UmidadePercentualTruncada;    char FieldUmidade[11];         if (client.connected())    {        client.stop();        Serial.println("- Disconnected from ThingSpeak");        Serial.println();    }     UmidadePercentualLida = FazLeituraUmidade();    UmidadePercentualTruncada = (int)UmidadePercentualLida;         if(!client.connected() && (millis() - lastConnectionTime > INTERVALO_ENVIO_THINGSPEAK))    {        sprintf(FieldUmidade,"field1=%d",UmidadePercentualTruncada);        EnviaInformacoesThingspeak(FieldUmidade);    }      delay(1000);}