Question

this is code to Temperature and Humidity Monitoring over ThingSpeak using Arduino UNO and ESP8266 i need someone explain the steps for me

#include <stdlib.h>

#include <DHT.h>

#define DHTPIN 5         // DHT data pin connected to Arduino pin 5

#define DHTTYPE DHT11     // DHT11 (DHT Sensor Type )

DHT dht(DHTPIN, DHTTYPE); // Initialize the DHT sensor

#define SSID "WiFi Name"     // "WiFi Name"

#define PASS "WiFi Password"       // "Password"

#define IP "184.106.153.149"// thingspeak.com ip

String msg = "GET /update?key=Your API Key"; //change it with your key...

float temp;

int hum;

String tempC;

int error;

void setup()

{

Serial.begin(115200); // use default 115200.

  Serial.println("AT");

delay(5000);

if(Serial.find("OK")){

    connectWiFi();

}

}

void loop(){

   start:

error=0;

temp = dht.readTemperature();

hum = dht.readHumidity();

char buffer[10];

tempC = dtostrf(temp, 4, 1, buffer);

updateTemp();

if (error==1){

    goto start;

}

delay(5000);

}

void updateTemp(){

String cmd = "AT+CIPSTART=\"TCP\",\"";

cmd += IP;

cmd += "\",80";

Serial.println(cmd);

delay(2000);

if(Serial.find("Error")){

    return;

}

cmd = msg ;

cmd += "&field1=";  

cmd += tempC;

cmd += "&field2=";

cmd += String(hum);

cmd += "\r\n";

Serial.print("AT+CIPSEND=");

Serial.println(cmd.length());

if(Serial.find(">")){

    Serial.print(cmd);

}

else{

    Serial.println("AT+CIPCLOSE");

    //Resend...

    error=1;

}

}

boolean connectWiFi(){

Serial.println("AT+CWMODE=1");

delay(2000);

String cmd="AT+CWJAP=\"";

cmd+=SSID;

cmd+="\",\"";

cmd+=PASS;

cmd+="\"";

Serial.println(cmd);

delay(5000);

if(Serial.find("OK")){

    return true;

}else{

    return false;

}

}

Answer 1

The explanation is given with comment (//) mark in the right side: (in bold)

#include <stdlib.h> //header file containing the library definitions, inside variables, commands etc.

#include <DHT.h> //same (.h file)

#define DHTPIN 5         // DHT data pin connected to Arduino pin 5

#define DHTTYPE DHT11     // DHT11 (DHT Sensor Type )

DHT dht(DHTPIN, DHTTYPE); // Initialize the DHT sensor

#define SSID "WiFi Name"     // "WiFi Name"

#define PASS "WiFi Password"       // "Password"

#define IP "184.106.153.149" // thingspeak.com ip

String msg = "GET /update?key=Your API Key"; //change it with your key...

float temp; \\setting up the temperature sensing via WiFi channeling

int hum;

String tempC;

int error; //error measurement, accuracy of the sensor

void setup()

{

Serial.begin(115200); // use default 115200.

  Serial.println("AT");

delay(5000); \\delay time

if(Serial.find("OK")){

    connectWiFi(); //connection to the wifi

}

}

void loop(){

   start: \\starting the system after connecting with wifi

error=0;

temp = dht.readTemperature(); //sensor reading the temperature

hum = dht.readHumidity();

char buffer[10]; //strings for temperature mesaurement

tempC = dtostrf(temp, 4, 1, buffer);

updateTemp();

if (error==1){ //if sensor doesn't read any input, start it again

    goto start;

}

delay(5000); //reading delay of 5 sec

}

void updateTemp(){

String cmd = "AT+CIPSTART=\"TCP\",\""; //procedure to give input commands to temp sensor

cmd += IP;

cmd += "\",80";

Serial.println(cmd);

delay(2000);

if(Serial.find("Error")){

    return;

}

cmd = msg ;

cmd += "&field1=";  

cmd += tempC;

cmd += "&field2=";

cmd += String(hum);

cmd += "\r\n";

Serial.print("AT+CIPSEND=");

Serial.println(cmd.length());

if(Serial.find(">")){ \\after successful measurement print/output the temp. value to the display or screen

    Serial.print(cmd);

}

else{

    Serial.println("AT+CIPCLOSE");

    //Resend...

    error=1;

}

}

boolean connectWiFi(){

Serial.println("AT+CWMODE=1");

delay(2000);

String cmd="AT+CWJAP=\"";

cmd+=SSID;

cmd+="\",\"";

cmd+=PASS;

cmd+="\"";

Serial.println(cmd);

delay(5000);

if(Serial.find("OK")){

    return true;

}else{

    return false;

}

}