How can you modify the subscription to only receive control messages with payload 'START' and ignore others?

hard🚀 Application Q9 of 15

Raspberry Pi - MQTT for IoT

ASubscribe normally and filter messages in on_message callback by checking payload

BUse MQTT topic filter 'control/START' to receive only those messages

CSet broker to only forward 'START' messages to your client

DSubscribe to 'control/#' and use QoS 2 to filter payloads

Step-by-Step Solution

Solution:

Step 1: Understand MQTT topic filtering limits
MQTT topics filter by topic name, not payload content.
Step 2: Filter payload in client code
Subscribe to relevant topics and check payload in on_message callback.
Final Answer:
Subscribe normally and filter messages in on_message callback by checking payload -> Option A
Quick Check:
Filter payload in callback, not via topic [OK]

Quick Trick: Filter payload inside on_message callback [OK]

Common Mistakes:

MISTAKES

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