ESP8266_ Access to the core suite of Baidu Internet of things and use mqtt protocol for communication

1、 follow “ Quick start ” Quick start

1.1、 Operation process

Search Baidu AI Cloud , Registered account , Real name authentication ;

Get into “ product ”→“ The Internet of things ”→“ Internet of things core suite ”, There is an interface for creating instances , But I don't know how to use it ;

So first look at the document ,“ file ”→“ Internet of things core suite ”, Many descriptions about this , Operation guide 、 Development of guidelines 、API etc. ;

Find the information you need to know ：

• “ The core concept ”, stay “ Internet of things core suite ” Some basic concepts used in ;
• “ System limitations ”, Yes MQTT Description of relevant limit values ;
• “ Quick start ”, Follow this section , Can Create a new instance , New equipment , Add the template , And through mqtt.fx 1.7.1 Subscribe and publish information ;

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1.2、 Concepts learned during operation —— Templates

Add a template during the operation , What is a template ？ Let's see what's in the template ？

Look at this interface , There are... In the template “ Subject name ”,“ describe ”,“ jurisdiction ”;

MQTT You need to publish and subscribe to topics , Naturally, you need to set the topic name , The template is used to set the topic name when adding devices ;

Templates test There are two default topic names 、 A new topic name ：

• "$iot/{device Name}/msg"： subscribe , The cloud sends messages to clients ;
  • In the use of mqtt.fx When , Only this topic name can be used to subscribe to messages , You can't publish ;
• "$iot/{device Name}/events"： Release , The client sends messages to the cloud ;
  • In the use of mqtt.fx When , Only this topic name can be used to publish messages , Cannot subscribe to ;
• "$iot/{device Name}/user/both"： subscribe 、 Release
  • In the use of mqtt.fx When , You can use this topic name to subscribe to and publish messages ;

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 1.3、 Skills learned during operation —— user name 、 password

Although the user name and key are available when creating the device , But this is not a direct connection MQTT Username and password , To be encrypted , The following link is an online encryption calculator , The information to be entered can be found in the equipment details , And then click “ Get the current timestamp ”、“ Click calculate ” The following automatically generates .

however , Because I don't know much about MQTT, If you make a mistake, just disconnect , And you can't reconnect , The user name and password error will be displayed when reconnecting , You have to get the timestamp to generate a new user name and password , so much trouble , Then I found out The time stamp is filled in directly 0 The generated user name and password can also be established MQTT Connected , And it can be connected again after disconnection .

MQTT Connect information calculator - Baidu Tiangong IoT Core (bcebos.com)

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1.4、 Problems encountered

mqtt.fx Use 1.7.1 edition

mqtt.fx 1.7.0 The version does have bug, It can be connected to the cloud , But I can't subscribe 、 Release the news , Please use 1.7.1 edition ;

Wrong topic name resulted in MQTT disconnect

At first, I thought the connection was unstable 、 perhaps mqtt.fx Version problem , After all, I just used 1.7.0 There are indeed bug Well , Actually, I don't know MQTT agreement , Therefore, the subject name is filled in incorrectly, resulting in , I also found it on the way 1.3 User name and password settings in , Specific examples are as follows ;

For example, the device name is "mqttfx", stay mqtt.fx After successfully connecting to ：

stay subscribe Interface , You can subscribe to "$iot/mqttfx/user/both" and "$iot/mqttfx/msg", Other subscriptions will not take effect （ list ）, No reaction ;

stay publish Interface , Can pass "$iot/mqttfx/events"、"$iot/mqttfx/user/both" To post news , Once the topic name is selected incorrectly, it will be disconnected immediately MQTT Connect ;

 

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2、 Create two devices 、 Add rules , Realize two MQTT Client communication

2.1、 Briefly explain the idea

esp8266 Controlled equipment , Such as the courtesy lamp ;mqtt.fx It is a client that simulates the use of users , Like mobile phone. app The interface that can send the control light on and off .

from MQTT From the point of view of the agreement ,esp8266 and mqtt.fx All are MQTT client , Baidu AI Cloud is MQTT The server ;

esp8266 Message sent ,mqtt.fx You can receive ;

mqtt.fx Message sent ,esp8266 You can receive ;

So controlled devices and users , That is to say esp8266 and mqtt.fx Seems to be able to communicate directly , But not through cloud platform .

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2.2、 Create two devices

Create two devices on the cloud , Corresponding ESP8266 and mqtt.fx, All are test Templates , That is, the topic is named "$iot/{device Name}/user/both", You can subscribe and publish ;

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2.3、 Add rules

Even in the same instance , Different devices Can not be By subscribing to the same topic , To communicate , To add a rule ;

The rules , This is the configuration of data forwarding , Select data from the topic 1 Forward to topic 2;

I just created two devices , I began to think that devices can communicate directly under the same instance , Thinking about equipment “mqttfx” adopt "$iot/mqttfx/user/both" To post news , equipment “esp8266” Subscribe to topics "$iot/mqttfx/user/both", You can communicate , The actual test is not allowed .

So we want the two devices to be able to communicate with each other , Two rules need to be set , A will device “mqttfx” Forward the message to the device “”esp8266”, The other will be the device ”esp8266” Forward the message to the device “mqttfx”;

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Configure internal rules , Remember to enable  

such as mqttfx_to_esp8266, Data source selection "$iot/mqttfx/user/both", Data destination selection "$iot/esp8266/user/both";

It can be mqttfx Through the theme "$iot/mqttfx/user/both" The published data is forwarded to "$iot/esp8266/user/both";

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2.4、 Two MQTT Client communication

thus , It's ready to use mqtt.fx Simulation in two MQTT Data transmission between clients is realized , next step , That is, the devices in the cloud instance "esp8266" Replace the real ESP8266, Then still use mqtt.fx Impersonate another client .

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3、ESP8266 Use MQTT Protocol communication

3.1、 The code migration

Originally intended to use routines directly , But I found it was not connected wifi, Print all the time "no 402 found, reconnect after 1s", So the replacement of what was written before can be connected wifi Code for , And temporarily comment out the rest of the routine , Not yet. , After a long time, I finally gave up using routines directly , Instead, all the code required by the routine is ported to the previous engineering framework , There was an episode about makefile Of , How to create a new folder to save source files and header files , I don't even care ..... Now we have to go back to the configuration makefile Knowledge of , What you haven't learned is a pit , If you don't fill it in, you will fall in sooner or later .

3.1.1、 stay app Under the folder , New subfolders modules and mqtt, And add .c The documents are as follows

 3.1.2、 stay app/include Under the folder , New subfolders modules and mqtt, And add .h The documents are as follows

I put mqtt_config.h Also on the app/include/mqtt I'm off , Because it's all mqtt Related configuration , I want to put them together ;

 3.1.3、 Copy app/user Under the Makefile, Paste the app/modules and app/mqtt Under the table of contents

 3.1.4、 modify app/modules/Makefile and app/mqtt/Makefile, Replace with libxxx.a

 3.1.5、 modify app/Makefile, Yes 3 It's about , Indicate the location of the new source file and header file , also .a Static library  

3.1.6、 Copy user_main.c The content of

P.S. Because... Notice user_rf_cal_sector_set The content of is inconsistent with the previous , And this function is related to MQTT It is not relevant, so this function is not copied , It should be OK to copy it , But I haven't tried it myself, so here are the notes ;

This is the end of the migration , To sum up , Just copy mqtt and modules Source file and header file under , as well as user_main.c

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 3.2、 To configure mqtt_config.h

Where I make mosaics , It should be modified according to the content actually applied by Baidu AI Cloud ;

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 3.3、 modify user_main.c The topic to publish and subscribe to in is named "$iot/esp8266/user/both"

 

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 3.4、 Turn on debug.h Print in

I found this problem after downloading it ,debug.h It is not enabled by default INFO, So in the program INFO The printed information will not be displayed , Remember to add the following macro definitions ：

#define GLOBAL_DEBUG_ON

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3.4、 compile 、 download , verification

open mqtt.fx, Put the device "mqttfx" Connect to the cloud , subscribe "$iot/mqttfx/user/both";

Reset esp8266, equipment "esp8266" Connect to the cloud , Sent "ESP8266_Online", Can be found in mqttfx You can receive , Again because "$iot/esp8266/user/both" The permission of is both publish and subscribe , therefore esp8266 I also received "ESP8266_Online";

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equipment "mqttfx" In the theme "$iot/mqttfx/user/both" Next send "LED_ON", equipment "esp8266" Received subject "$iot/esp8266/user/both" Of "LED_ON", And the light is on ;

Empathy , send out "LED_OFF",esp8266 The light goes out ;