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Introduction In this tutorial, you will learn how to use Node-RED, a visual programming tool for the Internet of Things (IoT), to control an LED on an ESP32 board with a Raspberry Pi as the MQTT broker. MQTT is a lightweight and simple messaging protocol that allows devices to communicate with each other over a network. You will need the following components for this project: ESP32 development board USB cable to connect the ESP32 to your computer Raspberry Pi with Node-RED Computer with Arduino IDE and PubSubClient library installed Get PCBs For Your Projects Manufactured You must check out PCBWAY for ordering PCBs online for cheap! You get 10 good-quality PCBs manufactured and shipped to your doorstep for cheap. You will also get a discount on shipping on your first order. Upload your Gerber files onto PCBWAY to get them manufactured with good quality and quick turnaround time. PCBWay now could provide a complete product solution, from design to enclosure production. Check out their online Gerber viewer function. With reward points, you can get free stuff from their gift shop. Step 1: Create a Device on Qubitro The first step is to create a device on the Qubitro platform. A device represents your physical device (Raspberry Pi) on the cloud. You need to create a device to obtain the MQTT credentials and topics for your Raspberry Pi. To create a device on Qubitro, follow these steps: 1. Log in to your Qubitro account and create a new project 2. Then go to the Devices page, select MQTT as the communication protocol, and click Next. 3. Enter all the details. 4. Copy the Device ID, Device Token, Hostname, Port, Publish Topic, and Subscribe Topic. You will need these values later in the code. Click Finish. You have successfully created a device on Qubitro. You can see your device on the Devices page. Step 2: Flash ESP32 with Arduino IDE The ESP32 is a powerful and versatile microcontroller that can run Arduino code. You will use the Arduino IDE to program the ESP32 and make it communicate with the MQTT broker using the PubSubClient library. To install the ESP32 board in Arduino IDE, you can follow the instructions in this tutorial or use the steps below: Open the preferences window from the Arduino IDE: File > Preferences. Go to the “Additional Board Manager URLs” field and enter the following URL: https://dl.espressif.com/dl/package_esp32_index.json. Open Boards Manager (Tools > Board > Boards Manager), search for ESP32, and click the install button for the “ESP32 by Espressif Systems”. Select your ESP32 board from Tools > Board menu after installation. Open the library manager from Sketch > Include Library > Manage Libraries. Search for PubSubClient and click the install button for the “PubSubClient by Nick O’Leary”. Restart your Arduino IDE after installation. Step 3: Connect LED to ESP32 The LED is a simple device that emits light when current flows through it. You will connect the LED to one of the GPIO pins of the ESP32 and control its state (on or off) with MQTT messages. In my case I'm going to use the onboard LED in the ESP32 Dev board. Step 4: Write Code for ESP32 The code for the ESP32 will do the following tasks: Connect to your Wi-Fi network Connect to the Qubitro MQTT broker on Raspberry Pi Receive messages from “output” and turn on or off the LED accordingly You can copy and paste the code below into your Arduino IDE. Make sure to replace <your_ssid>, <your_password>, <your_Qubtro_Credientials> with your own values. #include <WiFi.h> #define DEBUG_SW 1 #include <PubSubClient.h> //Relays for switching appliances #define Relay1 2 int switch_ON_Flag1_previous_I = 0; // Update these with values suitable for your network. const char* ssid = "ELDRADO"; const char* password = "amazon123"; const char* mqtt_server = "broker.qubitro.com"; // Local IP address of Raspberry Pi const char* username = ""; const char* pass = ""; // Subscribed Topics #define sub1 "output" WiFiClient espClient; PubSubClient client(espClient); unsigned long lastMsg = 0; #define MSG_BUFFER_SIZE (50) char msg[MSG_BUFFER_SIZE]; int value = 0; // Connecting to WiFi Router void setup_wifi() { delay(10); // We start by connecting to a WiFi network Serial.println(); Serial.print("Connecting to "); Serial.println(ssid); WiFi.mode(WIFI_STA); WiFi.begin(ssid, password); while (WiFi.status() != WL_CONNECTED) { delay(500); Serial.print("."); } randomSeed(micros()); Serial.println(""); Serial.println("WiFi connected"); Serial.println("IP address: "); Serial.println(WiFi.localIP()); } void callback(char* topic, byte* payload, unsigned int length) { Serial.print("Message arrived ["); Serial.print(topic); Serial.print("] "); if (strstr(topic, sub1)) { for (int i = 0; i < length; i++) { Serial.print((char)payload[i]); } Serial.println(); // Switch on the LED if an 1 was received as first character if ((char)payload[0] == 'f') { digitalWrite(Relay1, LOW); // Turn the LED on (Note that LOW is the voltage level // but actually the LED is on; this is because // it is active low on the ESP-01) } else { digitalWrite(Relay1, HIGH); // Turn the LED off by making the voltage HIGH } } else { Serial.println("unsubscribed topic"); } } // Connecting to MQTT broker void reconnect() { // Loop until we're reconnected while (!client.connected()) { Serial.print("Attempting MQTT connection..."); // Create a random client ID String clientId = "ESP8266Client-"; clientId += String(random(0xffff), HEX); // Attempt to connect if (client.connect(clientId.c_str() , username, pass)) { Serial.println("connected"); // Once connected, publish an announcement... client.publish("outTopic", "hello world"); // ... and resubscribe client.subscribe(sub1); } else { Serial.print("failed, rc="); Serial.print(client.state()); Serial.println(" try again in 5 seconds"); // Wait 5 seconds before retrying delay(5000); } } } void setup() { pinMode(Relay1, OUTPUT); Serial.begin(115200); setup_wifi(); client.setServer(mqtt_server, 1883); client.setCallback(callback); } void loop() { if (!client.connected()) { reconnect(); } client. Loop(); } After writing the code, upload it to your ESP32 board by selecting the right board and port from the Tools menu and clicking the upload button. Step 5: Create Node-RED Flow The Node-RED flow will do the following tasks: Connect to the MQTT broker on Raspberry Pi Subscribe to a topic named “output” Publish messages “true” or “false” to a topic named “output” Create a dashboard with a button and a text node You can create the Node-RED flow by dragging and dropping nodes from the palette and connecting them with wires. You can also import the flow from this link or use the JSON code below: [ { "id": "eb8f9c0d054be30c", "type": "tab", "label": "Flow 2", "disabled": false, "info": "", "env": [] }, { "id": "4ce6cd876fd5441f", "type": "mqtt out", "z": "eb8f9c0d054be30c", "name": "", "topic": "output", "qos": "", "retain": "", "respTopic": "", "contentType": "", "userProps": "", "correl": "", "expiry": "", "broker": "6d40b7b21c734b53", "x": 870, "y": 240, "wires": [] }, { "id": "974a7a8bb6db9bf9", "type": "mqtt in", "z": "eb8f9c0d054be30c", "name": "", "topic": "output", "qos": "2", "datatype": "auto-detect", "broker": "6d40b7b21c734b53", "nl": false, "rap": true, "rh": 0, "inputs": 0, "x": 670, "y": 320, "wires": [ [ "d0dc7378c7bfb03b", "f1219a2eeabe825f" ] ] }, { "id": "d0dc7378c7bfb03b", "type": "debug", "z": "eb8f9c0d054be30c", "name": "debug 4", "active": true, "tosidebar": true, "console": false, "tostatus": false, "complete": "payload", "targetType": "msg", "statusVal": "", "statusType": "auto", "x": 880, "y": 320, "wires": [] }, { "id": "6bd227b280e372b7", "type": "ui_switch", "z": "eb8f9c0d054be30c", "name": "", "label": "Light One", "tooltip": "", "group": "cd687a95.00e108", "order": 0, "width": 0, "height": 0, "passthru": true, "decouple": "false", "topic": "topic", "topicType": "msg", "style": "", "onvalue": "true", "onvalueType": "bool", "onicon": "", "oncolor": "", "offvalue": "false", "offvalueType": "bool", "officon": "", "offcolor": "", "animate": false, "x": 680, "y": 240, "wires": [ [ "4ce6cd876fd5441f" ] ] }, { "id": "f1219a2eeabe825f", "type": "ui_text", "z": "eb8f9c0d054be30c", "group": "cd687a95.00e108", "order": 1, "width": "6", "height": "2", "name": "", "label": "Status : ", "format": "{{msg.payload}}", "layout": "row-center", "x": 1060, "y": 320, "wires": [] }, { "id": "6d40b7b21c734b53", "type": "mqtt-broker", "name": "Qubitro Downlink", "broker": "broker.qubitro.com", "port": "1883", "clientid": "", "autoConnect": true, "usetls": false, "protocolVersion": "4", "keepalive": "60", "cleansession": true, "autoUnsubscribe": true, "birthTopic": "r43MsJYzcVwZtUXVfZo6XD0Ym7CRegewPQXMt$ho", "birthQos": "0", "birthPayload": "", "birthMsg": {}, "closeTopic": "", "closeQos": "0", "closePayload": "", "closeMsg": {}, "willTopic": "", "willQos": "0", "willPayload": "", "willMsg": {}, "userProps": "", "sessionExpiry": "" }, { "id": "cd687a95.00e108", "type": "ui_group", "name": "ESP32 Home Controller", "tab": "aa146f4d.b53ca", "order": 1, "disp": true, "width": "6", "collapse": false }, { "id": "aa146f4d.b53ca", "type": "ui_tab", "name": "Demo Lab", "icon": "dashboard", "order": 1, "disabled": false, "hidden": false } ] The input switch will send "true" when it is on, and it will send "false" when it triggers off. Then click on the Qubitro uplink pallet and edit the property. Here you need to replace your connection details and credentials. Next, just deploy the flow. And navigate to the /ui of the node-red server. Here you can toggle the switch to turn the lead on and off. Also, open the serial monitor and check the node-red response. Conclusion: In this tutorial, we have seen how to control the LED with Node-Red and MQTT Server.

What is Qubitro? Qubitro is an IoT (Internet of Things) platform that provides tools and services for connecting, managing, and analyzing IoT devices and data. It provides a cloud-based platform where users can securely connect their IoT devices and collect data from sensors and actuators. It supports a wide range of communication protocols and provides device management capabilities, monitoring device data, linking with third-party webhooks, and creating rules to trigger based on conditions, etc. All of it with a Great UI ❤ Get PCBs for Your Projects Manufactured You must check out PCBWAY for ordering PCBs online for cheap! You get 10 good-quality PCBs manufactured and shipped to your doorstep for cheap. You will also get a discount on shipping on your first order. Upload your Gerber files onto PCBWAY to get them manufactured with good quality and quick turnaround time. PCBWay now could provide a complete product solution, from design to enclosure production. Check out their online Gerber viewer function. With reward points, you can get free stuff from their gift shop. Getting Started To get started with Qubitro, we will first need to create an account. Go to the Qubitro website (https://www.qubitro.com/) and click on the "Sign Up" button. You will be prompted to enter Full Name, Email Address,Country, and password to create your account. Once, we have created the account, we can log in from https://portal.qubitro.com/login. However, we shall automatically be logged in to our account. Create a New Project Once you have logged in, you will be prompted to create a project. Enter a name for your project and mention a description for your project. Add Devices Next, you will need to add devices to your application. Go to the Project (if not already open), there we can see a button [+ New Source]. From this section, we will have 3 major sections - 1. Communication Protocol With a prompt to choose between LoRaWAN, MQTT, & Cellular. We can choose the protocol that best suits our use-case. I choose MQTT to get started with the platform basics. And since I shall be using Arduino IDE for programming the board, I went ahead with the MQTT Broker (Qubitro has its own broker - we shall see it in the upcoming section). In case you wish to know how the Toit platform works, you can check my Tutorial on Toit.io 2. Device Details I shall be using an ESP32 Dev Board, and therefore entered the details as per the image below - 3. Credentials In the next step, we receive credentials, to connect to the MQTT Broker. We can use this detail to connect to the broker as a client - to Publish or Subscribe. Now that we have the server, port, username and password we are all ready to send data to the Qubitro Cloud. Copy these details in a safe place (We can view them later in the device settings as well though) Hardware - From Device to Cloud Once you have configured your devices, you can start collecting data. Qubitro provides a range of tools for data collection and analysis, including real-time data visualization, data logging, and data filtering. We shall upload a code on ESP32 using Arduino IDE to send data to Qubitro - #include <WiFiClientSecure.h> #include <PubSubClient.h> #include <HTTPClient.h> #include <ArduinoJson.h> These are the necessary libraries for establishing an MQTT connection, handling HTTP requests, and working with JSON data. const char* ssid = "xxxxxxxxx"; const char* password = "xxxxxxxxx"; String topic = "xxxxx"; String mqtt_server = "broker.qubitro.com"; String mqttuser = "xxxxxxxxxxxxxxxxxxxxxx"; String mqttpass = "xxxxxxxxxxxxxxxxxxxxxx"; String clientId = "xxxxxxxxxxxxxxxxxxxxxx"; These variables store the Wi-Fi credentials (ssid and password), MQTT broker server address (mqtt_server), MQTT authentication credentials (mqttuser and mqttpass), MQTT client ID (clientId), and the MQTT topic (topic) to which the data will be published. WiFiClientSecure espClient; PubSubClient client(espClient); float humidity = 0; float temp = 0; Create an instance of WiFiClientSecure and PubSubClient classes to establish a secure connection with the MQTT broker. Also, initializing default value of temperature and humidity. #define MSG_BUFFER_SIZE (500) char msg[MSG_BUFFER_SIZE]; char output[MSG_BUFFER_SIZE]; Define the size of the message buffer for storing MQTT messages. void device_setup() { // ... Wi-Fi connection setup ... } This function sets up the Wi-Fi connection by connecting to the specified Wi-Fi network (ssid and password). void reconnect() { // ... MQTT reconnection logic ... } This function handles the reconnection to the MQTT broker in case of disconnection. void setup() { // ... Initialization code ... } The setup() function is the entry point of the code. It initializes the serial communication, sets up the device, establishes a connection with the MQTT broker, and prepares the secure connection using WiFiClientSecure and PubSubClient objects. void loop() { // ... Main code loop ... } The loop() function is the main execution loop of the code. It checks the MQTT connection, publishes the simulated temperature and humidity data to the MQTT topic, and then waits for a delay of 1 second before repeating the process. Inside the loop() function, you'll notice the following steps: if (!client.connected()) checks if the MQTT client is connected. If not, it calls the reconnect() function to establish the connection. client.loop() allows the MQTT client to maintain the connection and handle any incoming messages. The temp and humidity variables are randomly generated simulated values. A JSON document is created using the ArduinoJson library to store the temperature and humidity data. The JSON document is serialized into a string format using the serializeJson() function and stored in the output variable. The client.publish() function is used to publish the serialized JSON data to the specified MQTT topic. The serialized JSON data is printed to the serial monitor using Serial.println(). A delay of 1 second is added before repeating the loop. Full version of the code available in the Code Section. Now that we have written the code, upload it to the ESP32 board and wait for it to send data to cloud. To check data, go to Device Name that you created, and check for any incoming data in the table. (refresh the table in case data not retrieved) Create Dashboard Now that we were able to fetch for real-time data from the ESP32 board and view it on the table of Qubitro. Let us use the visualization feature to plot a graph of the data. Trust me, it takes seconds to setup the whole thing. Go to Dashboards, and create a New Dashboard. Give it a name. Once created, open it and go to Edit > Add Widget > Charts. Click on the new widget > three dots (settings) > Customization. Accordingly, select the data source, chart type and colour for data variables. Follow the below images for reference, and final Graph. Data source example above Data Point example above Finally, I received the above graph based on a 30-minute data logging. If we head back to the main dashboard page, we can have a proper view, and with a view configuration, receive live data in realtime on Qubitro. In the dashboard, click on the chart widget we created, click on edit and drag it to the middle. Stretch and play with the widget according to the need. Resizing it for proper viewing. Remember to save it. If you are facing trouble with viewing the data with 4 points in the graph period, you can change it in the View Mode's configuration of the graph widget. Now, using this we can view the data of our device based on our needs! Rules to Trigger and Integration Services Finally, Qubitro allows you to integrate with other services such as Twilio, Slack, MailGun, and SendGrid. We can also use the trigger for Webhooks (RAW HTTP request) triggering, You can do this by clicking on the "Rules" tab in the Device section and selecting the service you want to integrate with. Congratulations! You have now completed the Qubitro IoT Platform documentation tutorial. We hope that this tutorial has provided you with the information you need to get started with Qubitro and create your own IoT application. If you have any questions or need further assistance, please visit the Qubitro website or contact their support team. Hurray! 🎉 We have learned another IoT Platform - Qubitro Device Data Platform esp32_mqtt_qubitro.ino