Pada Project terakhir ini, kita akan belajar mempublikasikan pembacaan sensor ke Node-Red dengan ESP32 MQTT dan Arduino IDE. Kita akan melakukan komunikasi MQTT dengan ESP32 dan Node-Red dengan menerbitkan dan berlangganan topik MQTT. Kita akan mempublikasikan pembacaan sensor DS18B20, DHT, dan BME280 ke MQTT dengan ESP32, dan Dashboard Node-Red akan berlangganan topik MQTT dan menampilkan semua pembacaan sensor di Dashboard.

Komponen

• ESP32 board
• DHT11 sensor
• 10k ohm resistor
• BME280 sensor
• DS18B20 sensor
• 4.7k ohm resistor
• Breadboard
• Jumper Wires

Skema

Install Library pada Arduino IDE

Install Library DHT11

Untuk menginstall Library DHT11 dapat membaca disini

Install Library BME280

Untuk Instalasi Library BME280 bisa mengikuti pada project ini

Install Library DS18B20

Untuk Instalasi Library DS18B20 bisa ikuti langkah disini

Install Library MQTT

Untuk Instalasi Library MQTT dapat diikuti pada project-9

Install MQTT Broker pada Cloud

Install Node-Red pada Cloud

Kode

#include "DHT.h"
#include <WiFi.h>
extern "C" {
  #include "freertos/FreeRTOS.h"
  #include "freertos/timers.h"
}
#include <AsyncMqttClient.h>
#include <Wire.h>
#include <Adafruit_Sensor.h>
#include <Adafruit_BME280.h>
#include <OneWire.h>
#include <DallasTemperature.h>

//replace with your network credentials
#define WIFI_SSID "PTCL-08"
#define WIFI_PASSWORD "44332211"

// Raspberry Pi Mosquitto MQTT Broker
#define MQTT_HOST IPAddress(192, 168, 10, 8)
#define MQTT_PORT 1883

//MQTT Topics
#define MQTT_PUB_TEMP_DHT "esp32/dht/temperature"
#define MQTT_PUB_HUM_DHT  "esp32/dht/humidity"

#define MQTT_PUB_TEMP_BME280 "esp32/bme280/temperature"
#define MQTT_PUB_HUM_BME280  "esp32/bme280/humidity"
#define MQTT_PUB_PRES_BME280 "esp32/bme280/pressure"

#define MQTT_PUB_TEMP_C "esp32/ds18b20/temperatureC"
#define MQTT_PUB_TEMP_F "esp32/ds18b20/temperatureF"

#define DHTPIN 15  
#define DHTTYPE DHT22 
DHT dht(DHTPIN, DHTTYPE);

Adafruit_BME280 bme;

const int SensorDataPin = 4;   

OneWire oneWire(SensorDataPin);
DallasTemperature sensors(&oneWire);

float temperature_DHT, humidity_DHT; //variables for DHT
float temperature_BME280, humidity_BME280, pressure_BME280;   //variables for BME280
float temperature_Celsius, temperature_Fahrenheit;  //variables for DS18B20

AsyncMqttClient mqttClient;
TimerHandle_t mqttReconnectTimer;
TimerHandle_t wifiReconnectTimer;

unsigned long previousMillis = 0;   
const long interval = 10000;        

void connectToWifi() {
  Serial.println("Connecting to Wi-Fi...");
  WiFi.begin(WIFI_SSID, WIFI_PASSWORD);
}

void connectToMqtt() {
  Serial.println("Connecting to MQTT...");
  mqttClient.connect();
}

void WiFiEvent(WiFiEvent_t event) {
  Serial.printf("[WiFi-event] event: %dn", event);
  switch(event) {
    case SYSTEM_EVENT_STA_GOT_IP:
      Serial.println("WiFi connected");
      Serial.println("IP address: ");
      Serial.println(WiFi.localIP());
      connectToMqtt();
      break;
    case SYSTEM_EVENT_STA_DISCONNECTED:
      Serial.println("WiFi lost connection");
      xTimerStop(mqttReconnectTimer, 0); 
      xTimerStart(wifiReconnectTimer, 0);
      break;
  }
}

void onMqttConnect(bool sessionPresent) {
  Serial.println("Connected to MQTT.");
  Serial.print("Session present: ");
  Serial.println(sessionPresent);
}

void onMqttDisconnect(AsyncMqttClientDisconnectReason reason) {
  Serial.println("Disconnected from MQTT.");
  if (WiFi.isConnected()) {
    xTimerStart(mqttReconnectTimer, 0);
  }
}

void onMqttPublish(uint16_t packetId) {
  Serial.print("Publish acknowledged.");
  Serial.print("  packetId: ");
  Serial.println(packetId);
}

void setup() {
  Serial.begin(115200);
  Serial.println();

  dht.begin();
  delay(1000);

  if (!bme.begin(0x76)) {
    Serial.println("Could not detect a BME280 sensor, Fix wiring connections!");
    while (1);
  }
  delay(1000);

  sensors.begin();
  delay(1000);

  mqttReconnectTimer = xTimerCreate("mqttTimer", pdMS_TO_TICKS(2000), pdFALSE, (void*)0, reinterpret_cast<TimerCallbackFunction_t>(connectToMqtt));
  wifiReconnectTimer = xTimerCreate("wifiTimer", pdMS_TO_TICKS(2000), pdFALSE, (void*)0, reinterpret_cast<TimerCallbackFunction_t>(connectToWifi));

  WiFi.onEvent(WiFiEvent);

  mqttClient.onConnect(onMqttConnect);
  mqttClient.onDisconnect(onMqttDisconnect);
  mqttClient.onPublish(onMqttPublish);
  mqttClient.setServer(MQTT_HOST, MQTT_PORT);
  connectToWifi();
}

void loop() {
  unsigned long currentMillis = millis();
  if (currentMillis - previousMillis >= interval) {
    previousMillis = currentMillis;

    //Read from DHT
    humidity_DHT = dht.readHumidity();
    temperature_DHT = dht.readTemperature();

    if (isnan(temperature_DHT) || isnan(humidity_DHT)) {
      Serial.println(F("Failed to read from DHT sensor!"));
      return;
    }
    //delay(3000);

    //Read from BME280
    temperature_BME280 = bme.readTemperature();
    humidity_BME280 = bme.readHumidity();
    pressure_BME280 = bme.readPressure() / 100.0F;
    //delay(3000);

    //Read from DS18B20
    sensors.requestTemperatures(); 
    temperature_Celsius = sensors.getTempCByIndex(0);
    temperature_Fahrenheit = sensors.getTempFByIndex(0);
    //delay(3000);

    // Publish an MQTT message on topic esp32/dht/temperature
    uint16_t packetIdPub1 = mqttClient.publish(MQTT_PUB_TEMP_DHT, 1, true, String(temperature_DHT).c_str());                            
    Serial.printf("Publishing on topic %s at QoS 1, packetId: %i", MQTT_PUB_TEMP_DHT, packetIdPub1);
    Serial.printf("Message: %.2f \n", temperature_DHT);

    // Publish an MQTT message on topic esp32/dht/humidity
    uint16_t packetIdPub2 = mqttClient.publish(MQTT_PUB_HUM_DHT, 1, true, String(humidity_DHT).c_str());                            
    Serial.printf("Publishing on topic %s at QoS 1, packetId %i: ", MQTT_PUB_HUM_DHT, packetIdPub2);
    Serial.printf("Message: %.2f \n", humidity_DHT);

        // Publish an MQTT message on topic esp32/bme280/temperature
    uint16_t packetIdPub3 = mqttClient.publish(MQTT_PUB_TEMP_BME280, 1, true, String(temperature_BME280).c_str());                            
    Serial.printf("Publishing on topic %s at QoS 1, packetId: %i", MQTT_PUB_TEMP_BME280, packetIdPub3);
    Serial.printf("Message: %.2f \n", temperature_BME280);

    // Publish an MQTT message on topic esp32/bme280/humidity
    uint16_t packetIdPub4 = mqttClient.publish(MQTT_PUB_HUM_BME280, 1, true, String(humidity_BME280).c_str());                            
    Serial.printf("Publishing on topic %s at QoS 1, packetId %i: ", MQTT_PUB_HUM_BME280, packetIdPub4);
    Serial.printf("Message: %.2f \n", humidity_BME280);


    // Publish an MQTT message on topic esp32/bme280/pressure
    uint16_t packetIdPub5 = mqttClient.publish(MQTT_PUB_PRES_BME280, 1, true, String(pressure_BME280).c_str());                            
    Serial.printf("Publishing on topic %s at QoS 1, packetId %i: ", MQTT_PUB_PRES_BME280, packetIdPub5);
    Serial.printf("Message: %.2f \n", pressure_BME280);

    // Publish an MQTT message on topic esp32/ds18b20/temperatureC
    uint16_t packetIdPub6 = mqttClient.publish(MQTT_PUB_TEMP_C, 1, true, String(temperature_Celsius).c_str());                            
    Serial.printf("Publishing on topic %s at QoS 1, packetId: %i", MQTT_PUB_TEMP_C, packetIdPub6);
    Serial.printf("Message: %.2f \n", temperature_Celsius);

    // Publish an MQTT message on topic esp32/ds18b20/temperatureF
    uint16_t packetIdPub7 = mqttClient.publish(MQTT_PUB_TEMP_F, 1, true, String(temperature_Fahrenheit).c_str());                            
    Serial.printf("Publishing on topic %s at QoS 1, packetId %i: ", MQTT_PUB_TEMP_F, packetIdPub7);
    Serial.printf("Message: %.2f \n", temperature_Fahrenheit);
  }
}

Serial Monitor

Konfigurasi Node-Red

Visualisasi