MQTT Subscribe

R2026b

Subscribe to an MQTT topic and receive message from the broker

Since R2023a

• 

MQTT Subscribe block

To add a block to a model, double-click the canvas and start typing the block name. Then, select the block from the list.

Libraries:
Simulink Support Package for Android Devices / Communication

Description

Add-On Required: This feature requires the Simulink Support Package for Android Devices add-on.

Use the MQTT Subscribe block to receive messages from the message queuing telemetry transport (MQTT) broker on the specified topic.

Ports

Output

Data Length — Length of data

scalar (default)

The port outputs the actual length of the data received from the MQTT broker.

Data Types: int32

Data — Data received from MQTT broker

scalar

The block outputs the data received from the MQTT broker as an array of ASCII characters.

Data Types: uint8

Parameters

Topic — Topic for subscription

channels/<channelID>/subscribe (default) | any valid topic name

Specify a topic to which the client subscribes. A topic can have a maximum of 128 characters. For information on topics and their structure, see Topics in MQTT.

Maximum length of output message — Maximum length of data read from the MQTT broker

256 (default) | positive integer

Specify the maximum length of the data you want to receive at each sample time.

Sample time — Frequency to check for messages from MQTT broker

1 (default) | -1 | scalar

Specify how often the client checks for a new message from the broker. When you specify the sample time as -1, the block inherits its sample time based on the context of the block within the model.

Programmatic Use: Add Block

To add the block programmatically, use the add_block function with one of these library block paths as the source.

"androidcommunicationlib/MQTT Subscribe"

Example: add_block("androidcommunicationlib/MQTT Subscribe","myModel/myBlock",MakeNameUnique="on")

Version History

Introduced in R2023a