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Cmtelesann
Published

MQTT Communication Between NodeMCU and Raspberry Pi 3 B+

Using MQTT, NodeMCU, DHT22, RaspberryPi and IoT MQTT Panel to monitor temperature and humidity.

IntermediateFull instructions provided3 hours8,089
MQTT Communication Between NodeMCU and Raspberry Pi 3 B+

Things used in this project

Hardware components

Raspberry Pi 3 Model B+
Raspberry Pi 3 Model B+
×1
NodeMCU ESP8266 Breakout Board
NodeMCU ESP8266 Breakout Board
×9
DHT22 Temperature and Humidity Sensor
DFRobot DHT22 Temperature and Humidity Sensor
×9
Female/Female Jumper Wires
Female/Female Jumper Wires
×27

Software apps and online services

Raspbian
Raspberry Pi Raspbian
Thonny Python IDE
IoT MQTT Panel

Story

Read more

Schematics

NodeMCU + DHT-22

Code

Raspberry Pi

Python
Have this script on your Raspberry Pi. Remember to include your Blynk Auth number, BrokerIPAddress and check the topics subscribed.
#V1.0 - No blynk connectivity as they decided to create a new product with no backwards compatibility.
import time
import paho.mqtt.client as mqtt

# Don't forget to change the variables for the MQTT broker!
mqtt_broker_ip = "Broker_IP_Address"
client=mqtt.Client()
    
#Setup callback functions that are called when MQTT events happen linke connecting to the server or receiving data from a subscribed feed.
def on_connect(client, userdata, flags, rc):
    print("Connected with result code" + str(rc))
    client.subscribe("/#")

#The callback for when a PUBLISH message is recieved from the server
def on_message(client, userdata, msg):
    msg.payload = msg.payload.decode("utf-8") #to decode message, remove b and ''
  # Show status of sensors  
    #room1
    if msg.topic == "/room1/status":
        if msg.payload == "1":
            print ("Topic: ", msg.topic + "\nMessage: " + str(msg.payload))
    if msg.topic == "/room1/status":
        if msg.payload == "0":
            print ("Topic: ", msg.topic + "\nMessage: " + str(msg.payload))
    #room2
    if msg.topic == "/room2/status":
        if msg.payload == "1":
            print ("Topic: ", msg.topic + "\nMessage: " + str(msg.payload))
    if msg.topic == "/room2/status":
        if msg.payload == "0":
            print ("Topic: ", msg.topic + "\nMessage: " + str(msg.payload))
    #room3
    if msg.topic == "/room3/status":
        if msg.payload == "1":
            print ("Topic: ", msg.topic + "\nMessage: " + str(msg.payload))
    if msg.topic == "/room3/status":
        if msg.payload == "0":
            print ("Topic: ", msg.topic + "\nMessage: " + str(msg.payload))
    #room4
    if msg.topic == "/room4/status":
        if msg.payload == "1":
            print ("Topic: ", msg.topic + "\nMessage: " + str(msg.payload))
    if msg.topic == "/room4/status":
        if msg.payload == "0":
            print ("Topic: ", msg.topic + "\nMessage: " + str(msg.payload))

    #Print humidity and temperature values
    if msg.topic == "/room1/temperature":
        print ("Topic: ", msg.topic + "\nMessage: " + str(msg.payload))
    if msg.topic == "/room1/humidity":
        print ("Topic: ", msg.topic + "\nMessage: " + str(msg.payload))
    if msg.topic == "/room2/temperature":
        print ("Topic: ", msg.topic + "\nMessage: " + str(msg.payload))
    if msg.topic == "/room2/humidity":
        print ("Topic: ", msg.topic + "\nMessage: " + str(msg.payload))
    if msg.topic == "/room3/temperature":
        print ("Topic: ", msg.topic + "\nMessage: " + str(msg.payload))
    if msg.topic == "/room3/humidity":
        print ("Topic: ", msg.topic + "\nMessage: " + str(msg.payload))
    if msg.topic == "/room4/temperature":
        print ("Topic: ", msg.topic + "\nMessage: " + str(msg.payload))
    if msg.topic == "/room4/humidity":
        print ("Topic: ", msg.topic + "\nMessage: " + str(msg.payload))
 
# Here, we are telling the client which functions are to be run
# on connecting, and on receiving a message
client.on_connect = on_connect
client.on_message = on_message

# Once everything has been set up, we can (finally) connect to the broker
# 1883 is the listener port that the MQTT broker is using
client.connect(mqtt_broker_ip, 1883)

# Once we have told the client to connect, let the client object run itself
client.loop_forever()
client.disconnect()
time.sleep(30)

NodeMCU

Arduino
This code should be used on a NodeMCU. Remember to change the device name for debugging purposes. Also put your broker IP Address.
/* REQUIRES the following Arduino libraries:
 - DHT Sensor Library: https://github.com/adafruit/DHT-sensor-library
 - Adafruit Unified Sensor Lib: https://github.com/adafruit/Adafruit_Sensor
 - MQTT library
*/

#include <ESP8266WiFi.h>                              // Esp8266/NodeMCU Library
#include <PubSubClient.h>                             // MQTT Library
#include "DHT.h"                                      // DHT Sensor

const char* mqtt_server = "Broker_IP_Address";             // MQTT Server IP Address
const char* clientID = "Room1";                        // The client id identifies the NodeMCU device.
const char* topicT = "/Room1/temperature";             // Topic temperature
const char* topicH = "/Room1/humidity";                // Topic humidity
const char* willTopic = "/Room1/status";               // Topic Status
int willQoS = 0;
boolean willRetain = true;                           
const char* willMessage = "0";                        // 0 - Disconnecetd
int counter = 0;                                      // Used to reconnect to MQTT server
const char* swversion = "1.0";                        // Software version

WiFiClient wifiClient;
PubSubClient client(mqtt_server, 1883, wifiClient);   // 1883 is the listener port for the Broker

DHT dhtA(2, DHT22);                                   // DHT instance named dhtA, Pin on NodeMCU D4 and sensor type

void setup() {
  Serial.begin(9600);                                 // Debug purposes only to check if DHT and connection with MQTT Broker are working
  Serial.print(swversion);                            // Debug. Software version
    
  dhtA.begin();                                       // Starting the DHT-22
  delay(2000);                                        // Delay to allow first connection with MQTT Broker
    
  if (client.connect(clientID,"","", willTopic, willQoS, willRetain, willMessage, true)) {  // Connecting to MQTT Broker
    client.publish(willTopic, "1", true);
    Serial.print(clientID);
    Serial.println(" connected to MQTT Broker!");
  }
  else {
    Serial.print(clientID);
    Serial.println(" connection to MQTT Broker failed...");
  }                                 

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

void loop() {
  climateRoutine();                                   // Climate routines 
  if (!client.connected()) {                          // Reconnecting to MQTT server if connection is lost
    reconnect();
  } 
}

void climateRoutine() {
  char temp[16];
  dtostrf(dhtA.readTemperature(), 3, 2, temp);        // To convert float into char
  client.publish(topicT, temp);                       // Publishing temperature 
                 
  char humi[16];
  dtostrf(dhtA.readHumidity(), 3, 2, humi);           // To convert float into char
  client.publish(topicH, humi);                       // Publishing humidity 
    
  if (isnan(temp[16]) || isnan(humi[16])) {           // Check if there DHT is working
    Serial.println("Failed to read from DHT sensor!");
    return;
  }
  delay(1000);                                        // Delay to avoid flooding system with data
}

void reconnect() {                                    // Reconnecting to MQTT server if connection is lost
 while (!client.connected()) {
   Serial.print("Attempting MQTT connection...");
   if (client.connect(clientID,"","", willTopic, willQoS, willRetain, willMessage, true)) { // clean session, last will message will be kept
     client.publish(willTopic, "1", true);            // Publishing willmessage, retained, so when it disconnects publishers will get the message even if the publisher itself has disconnected
     Serial.println("Connected to MQTT Broker!");
     counter = 0;
   } else {
     Serial.println("Connection to MQTT Broker failed. Trying again in 2 seconds");
     ++counter;
     if (counter > 180) ESP.reset();
     delay(2000);
   }
 }
}

Credits

Cmtelesann

Cmtelesann

5 projects • 15 followers
Keeping my head busy! Looking for challenges! Trying to keep up with evolution! IoT is the future!
Thanks to Ruchir Sharma, DIY Projects, and Steve.

Comments

Related channels and tags
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