2. NodeMCU ESP-12E IoT: Publish the value

Publishing atau mengirim data ke internet adalah salah satu item dari IoT, hari ini kita akan belajar mengirim data dari NodeMCU ke internet, dimana data akan ditampilkan di web browser komputer atau mobile phone.

What we Need,

1. NodeMCU ESP-12E Development Board.

2. Mensetting Arduino IDE dan NodeMCU

3. Adafruit MQTT library

4. Copas source code dibawah ini:

ada beberapa yang harus diganti, menyesuaikan dengan data koneksi internet:

1. router SSID

2. roater Password

3. Adafruit username

4. adafruit IO Key

 

/***************************************************
  Adafruit MQTT Library ESP8266 Example

  Must use ESP8266 Arduino from:
    https://github.com/esp8266/Arduino

  Works great with Adafruit's Huzzah ESP board & Feather
  ----> https://www.adafruit.com/product/2471
  ----> https://www.adafruit.com/products/2821

  Adafruit invests time and resources providing this open source code,
  please support Adafruit and open-source hardware by purchasing
  products from Adafruit!

  Written by Tony DiCola for Adafruit Industries.
  MIT license, all text above must be included in any redistribution
 ****************************************************/
#include <ESP8266WiFi.h>
#include "Adafruit_MQTT.h"
#include "Adafruit_MQTT_Client.h"

/************************* WiFi Access Point *********************************/

#define WLAN_SSID       "YOUR ROUTER SSID"
#define WLAN_PASS       "YOUR ROUTER PASSWORD"

/************************* Information to Connect to Adafruit IO *********************************/
/*  You will need and account - Its FREE  */

#define AIO_SERVER      "io.adafruit.com"
#define AIO_SERVERPORT  1883                   // use 8883 for SSL
#define AIO_USERNAME    "YOUR ADAFRUIT USER NAME"
#define AIO_KEY         "YOUR ADAFRUIT IO KEY"

/************ Setting up your WiFi Client and MQTT Client ******************/

// Create an ESP8266 WiFiClient class to connect to the MQTT server.

WiFiClient client;

// Setup the MQTT client class by passing in the WiFi client and MQTT server and login details.
Adafruit_MQTT_Client mqtt(&client, AIO_SERVER, AIO_SERVERPORT, AIO_USERNAME, AIO_KEY);

/****************************** Set Up a Feed to Publish To ***************************************/

// Setup a feed called 'photocell' for publishing.
// Notice MQTT paths for AIO follow the form: <username>/feeds/<feedname>

Adafruit_MQTT_Publish myFirstValue = Adafruit_MQTT_Publish(&mqtt, AIO_USERNAME "/feeds/myFirstValue");


/********************* Values ******************************/
// Need a changing value to send.  We will increment this value
// in the getVal function.  
//we start at zero and when it gets to 10 we start over.

uint32_t xVal=-1;

/*************************** Sketch Code ***********************************************************/

// Bug workaround for Arduino 1.6.6, it seems to need a function declaration
// for some reason (only affects ESP8266, likely an arduino-builder bug).
void MQTT_connect();

void setup() {
  Serial.begin(115200);
  delay(10);

  Serial.println(F("Adafruit MQTT demo"));

  // Connect to WiFi access point.
  Serial.println(); Serial.println();
  Serial.print("Connecting to ");
  Serial.println(WLAN_SSID);

  WiFi.begin(WLAN_SSID, WLAN_PASS);
  while (WiFi.status() != WL_CONNECTED) {
    delay(500);
    Serial.print(".");
  }
  Serial.println();

  Serial.println("WiFi connected");
  Serial.println("IP address: "); Serial.println(WiFi.localIP());
 
}


void loop() {
  // Ensure the connection to the MQTT server is alive (this will make the first
  // connection and automatically reconnect when disconnected).  See the MQTT_connect
  // function definition further below.
  MQTT_connect();

  

  // Now we can publish stuff!
  Serial.print(F("\nSending myValue "));
  Serial.print((xVal-1));
  Serial.print("...");
  if (! myFirstValue.publish(getVal())) {
    Serial.println(F("Failed"));
  } else {
    Serial.println(F("OK!"));
  }

  // ping the server to keep the mqtt connection alive
  // NOT required if you are publishing once every KEEPALIVE seconds
  /*
  if(! mqtt.ping()) {
    mqtt.disconnect();
  }
  */
  delay(1000);
}

// Function to connect and reconnect as necessary to the MQTT server.
// Should be called in the loop function and it will take care if connecting.
void MQTT_connect() {
  int8_t ret;

  // Stop if already connected.
  if (mqtt.connected()) {
    return;
  }

  Serial.print("Connecting to MQTT... ");

  uint8_t retries = 3;
  while ((ret = mqtt.connect()) != 0) { // connect will return 0 for connected
       Serial.println(mqtt.connectErrorString(ret));
       Serial.println("Retrying MQTT connection in 5 seconds...");
       mqtt.disconnect();
       delay(5000);  // wait 5 seconds
       retries--;
       if (retries == 0) {
         // basically die and wait for WDT to reset me
         while (1);
       }
  }
  Serial.println("MQTT Connected!");
}


//  Use this increment myVal

uint8_t getVal(){

  if(xVal == 11){
      xVal = 0;
  }
  return xVal++;
  
}

Monitor data lewat serial monitoring Output

Bandingkan antara data di serial port dengan Nilai yang ada di adafruit.

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