MQTT Client Lite App - User Guide

This is a simple MQTT Client App. This App is targeted for engineers, technical hobbyists, and MQTT Network testers.

Recommendation

• For connection without TLS/SSL (unencrypted), port number 1883 is recommended. And for connection with TLS/SSL (encrypted), port number 8883 is recommended.

Features

• Connect to MQTT Broker.
• Enable or disable TLS/SSL option if required.
• Use authentication feature, if required for the connection.
• Publish messages to MQTT Topics. Once a message is published to a MQTT Topic, it will also be added to the subscription list.
• Subscribe to MQTT Topics.
• Monitor the subscribed MQTT Topics.
• Plot the numerical messages (payload) from a MQTT Topic. Other than numerical data received will be ignored while plotting.

Technical points

• To connect to MQTT Broker, Broker address and port is required.
• Client name (as this App is a MQTT Client, name is required), TLS/SSL option, username, and password are optional.
• If Client name is not provided, the App creates name starting with mbl_client_....
• Enable the TLS/SSL option if required for the conenction and communication.
• Username and password are required for authentication. It can for example be required by the MQTT Broker.
• This App use v3.1.1 MQTT version.
• For each new conenction, "Clean session" is always enabled.

Connecting to the MQTT Broker

To connect to the MQTT Broker, go to the Setting Screen, as shown in figure below:


Then, connection can be established with different option:

1. With only Broker Address and Port

This is recommended in local Network only. Since, here the data transmission and reception are unencrypted. Simply provide the MQTT Broker address and the Port number. The MQTT Broker must also be configured to accept the connection and communication without the TLS/SLL and without the authentication. In case the Client name is not provided, the App will generate Client name with starting mbl_***.

2. With Broker Address, Port and TLS/SSL enabled

To use the TLS/SSL option, it must be enabled in the App. This will allow encrypted communication throughout the MQTT Network.

3. With Broker Address, Port, and Authentication

If required, for example by the MQTT Broker, authentication credintials (username and password) must be provided.

Notes:

Client Name

The Client name is recommended. But in case it is not provided, the Client name will be generated by the App with starting mbl_***

Port number and TLS/SSL

As recommended, for connection without TLS/SSL (unencrypted), port number 1883 is recommended. And for connection with TLS/SSL (encrypted), port number 8883 is recommended. In case of use of wrong Port number, the App will raise error when detected.

Connected Status:

Once connected, the status Widget will turn Green, as in figure below:

Home Screen

In the Home Screen, firtly there is section to Publish MQTT messages, as shown in Section 1. Simply provide the MQTT Topic and Message to publish / send. On publishing Message to the MQTT Topic, the Topic is added also to the Subscription list. In the section 2, MQTT Topics can be subscribed to. In the Section 3, last Message / Payload can be seen for each subscribed MQTT Topics. Section 4 is to plot numerical values for selected MQTT Topic. Other than numerical values will be ignored.