【Distributed temperature and humidity collection system】+MQTT debugging

lansebuluo

【Distributed temperature and humidity collection system】+MQTT debugging [Copy link]

 

When debugging MQTT, because multiple modules and the same program were used, it was found that during the debugging process, when one module was online, it would squeeze out the connection of another module MQTT. After searching some posts and looking at the protocol, I finally figured out why.

There is a client ID. All modules are a program. The macro-defined ID is the same. After associating with the MAC address, the problem is solved. Please record it.

Before change:

#define MQTT_DEMO_CLIENT_ID "wm_mqtt_client"

mqtt_init(&mqtt_demo_mqtt_broker, MQTT_DEMO_CLIENT_ID);

After change:

mqtt_init(&mqtt_demo_mqtt_broker, deviceName);

deviceName is a MAC address string

lugl4313820

Thanks for sharing, this helps a lot.

damiaa

The clientID is a unique identifier for the device and must be globally unique. If different devices use the same clientID to connect to the IoT platform at the same time, the device that connects first will be forcibly disconnected.

wangerxian

[Will it squeeze out the connection of another module MQTT] Is this an operation performed by the server?

damiaa

wangerxian posted on 2022-10-20 09:41 [Will it squeeze out the connection of another module MQTT] Is it an operation performed by the server?

That should be the broker . How can the client know that someone is impersonating them ?

广西盟创智慧科技有限公司

Thanks for sharing!

wangerxian

damiaa posted on 2022-10-20 10:08 wangerxian posted on 2022-10-20 09:41 [Will it squeeze out the connection of another module MQTT] Is it an operation done by the server? Then it should be b ...

It is equivalent to being directly disconnected by the broker. Unless you reconnect, there will be no communication.