MQTT-Wokwi-Simulation

Simulating Message Queuing Telemetry Transport (MQTT) Protocol using Wokwi Simulator and Mosquitto Broker.

📦 Setup Environment

• Download and Install Mosquitto Broker for Windows.

• Add Mosquitto to PATH. Default Installation Directory for Mosquitto is:

  C:\Program Files\mosquitto
  

• Now, Open Notepad as Administrator and Save the following in the above directory by the name mosquitto.conf file.

  listener 1883 0.0.0.0
  protocol MQTT
  allow_anonymous true
  log_type all
  log_dest file C:\Program Files\mosquitto\mosquitto.log
  

• Verify Installation with mosquitto -v.

• Check for Mosquitto Subscriber and Publisher with mosquitto_sub --version or mosquitto_pub --version.

• Stop Mosquitto Broker service in Services.msc, if you get an error and re-check mosquitto -v.

• Test Basic Connection:

  mosquitto_sub -h test.mosquitto.org -t test/connect
  mosquitto_pub -h test.mosquitto.org -t test/connect -m "Hello MQTT!"
  

🤖 Circuit Layout and Topics

• For complete circuit diagrams and pin connections, refer to CONNECTIONS.md.

Base Topic: home/

graph TD
    A[home/] --> B[home/control]
    A --> C[home/summary]
    A --> D[home/rooms/]
    A --> E[home/control/response/]
    
    D --> F[home/rooms/room1]
    D --> G[home/rooms/kitchen]
    D --> H[home/rooms/gate]
    
    E --> I[home/control/response/client_id]

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Control Commands

Command	Action	Required Fields	Description	Response Topic	Example JSON
Subscribe	subscribe	client_id, rooms	Subscribe client to specific rooms	home/control/response/{client_id}	{"action": "subscribe", "client_id": "C-01", "rooms": ["room1", "kitchen"]}
Unsubscribe	unsubscribe	client_id, rooms	Unsubscribe client from specific rooms	home/control/response/{client_id}	{"action": "unsubscribe", "client_id": "C-01", "rooms": ["room1"]}
Disconnect	disconnect	client_id	Disconnect client from all rooms	home/control/response/{client_id}	{"action": "disconnect", "client_id": "C-01"}
Status	status	client_id	Get client subscription status	home/control/response/{client_id}	{"action": "status", "client_id": "C-01"}

🤔 How to Run?

• First, Go to Wokwi and Open Basic ESP32 Project.

• Create New File named main.py.

• From the repository, use the diagram.json and main.py.

• Run the code in Wokwi.

• Meanwhile, open Command Prompt and Subscribe to Topics to view messages.

Commands to Test Simulation

1. Monitor all Topics.

   mosquitto_sub -h test.mosquitto.org -t "home/#" -v

2. Monitor Specific Topics.

• Monitor Control Messages

  mosquitto_sub -h test.mosquitto.org -t "home/control/#" -v

• Monitor Room Readings

  mosquitto_sub -h test.mosquitto.org -t "home/rooms/#" -v

• Monitor System Summary

  mosquitto_sub -h test.mosquitto.org -t "home/summary" -v

3. Subscribe Client to Rooms

• Subscribe C-01 to gate only

  mosquitto_pub -h test.mosquitto.org -t "home/control" -m "{\"action\": \"subscribe\", \"client_id\": \"C-01\", \"rooms\": [\"gate\"]}"

• Subscribe C-02 to all rooms

  mosquitto_pub -h test.mosquitto.org -t "home/control" -m "{\"action\": \"subscribe\", \"client_id\": \"client3\", \"rooms\": [\"room1\", \"kitchen\", \"gate\"]}"

4. Monitor Client Status

   mosquitto_pub -h test.mosquitto.org -t "home/control" -m "{\"action\": \"status\", \"client_id\": \"C-01\"}"

5. Unsubscribe Client from Rooms

• Remove client2 from multiple rooms

  mosquitto_pub -h test.mosquitto.org -t "home/control" -m "{\"action\": \"unsubscribe\", \"client_id\": \"C-02\", \"rooms\": [\"kitchen\", \"gate\"]}"

6. Disconnect Client

   mosquitto_pub -h test.mosquitto.org -t "home/control" -m "{\"action\": \"disconnect\", \"client_id\": \"C-01\"}"

7. Monitor Specific Room Data

• Monitor room1 readings

  mosquitto_sub -h test.mosquitto.org -t "home/rooms/room1" -v

• Monitor kitchen readings

  mosquitto_sub -h test.mosquitto.org -t "home/rooms/kitchen" -v

• Monitor gate readings

  mosquitto_sub -h test.mosquitto.org -t "home/rooms/gate" -v