ESP8266 connects to Alibaba Cloud – MQTT protocol
MQTT (Message Queuing Telemetry Transport, Message Queuing Telemetry Transport Protocol) is a lightweight communication protocol based on the publish/subscribe (Publish/Subscribe) model, which is built on the TCP/IP protocol and released by IBM in 1999 . The biggest advantage of MQTT is that it can provide real-time and reliable message services for remote devices with very little code and limited bandwidth. As a low-overhead, low-bandwidth instant messaging protocol, MQTT has a wide range of applications in the Internet of Things, small devices, and mobile applications. MQTT is an application layer protocol. The latest version is the MQTT v5.0 standard. The connection to the Alibaba Cloud IoT platform is mainly based on the MQTT standard protocol version 3.1.
1. Register an Alibaba Cloud account and log in to the cloud platform
1. Search for the IoT platform and log in to the IoT platform.
2. Enter the IoT console
3. Select a public instance4
. Create a product
5. Add a product
Add a device successfully:
each device has its own triple, click the device name to view the device three groups: The
device triple is very Important, you will need to log in to the Alibaba Cloud platform later.
- Add product features
2. Create a project and connect to Alibaba Cloud
2.1 Write the ESP8266 driver and connect to Alibaba Cloud.
//TCP+STA模式，连接服务器
#define WIFI_NAME "WBYQ" //wifi名
#define WIFI_PASSWORD "asdfghjkl23"//WiFi密码
#define SERVER_IP "a1knXG89uwh.iot-as-mqtt.cn-shanghai.aliyuncs.com"//服务器ip
#define SERVER_PORT 1883//端口号
while(1)
{
stat=Esp8266_STA_TCPclinet_Init((u8 *)WIFI_NAME,(u8 *)WIFI_PASSWORD,(u8 *)SERVER_IP,SERVER_PORT);
if(stat==0)break;
Delay_Ms(500);
printf("stat=%d\r\n",stat);
}
printf("服务器连接成功\r\n");
For server ip and port number settings, please refer to Alibaba Cloud Online Documentation
Server IP Format:
${
YourProductKey}.iot-as-mqtt.${
YourRegionId}.aliyuncs.com:1883
${
YourProductKey}为设备的ProductKey，上面讲到设备三元组已提到过。
${
YourRegionId} 是区域代码,我这是属于华东2，区域代码:cn-shanghai
综上，服务器ip为 ”a1knXG89uwh.iot-as-mqtt.cn-shanghai.aliyuncs.com”
2.2 MQTT continuous server
MQTT connection to Alibaba Cloud requires three parameters: client id, user name, and password.
For filling in these three parameters, please refer to Alibaba Cloud Documentation Tool.
#define ClientID "STM32|securemode=3,signmethod=hmacsha1|"
#define Username "STM32&a17b5WKUY0S"
#define Password "ebff9579ed3e610228da8c035afc9636954c43bd"//密文
while(1)
{
MQTT_Init();
stat=MQTT_Connect(ClientID,Username,Password);
if(stat==0)break;
Delay_Ms(500);
printf("正在连接....\r\n");
}
printf("阿里云连接成功\r\n");
2.3 Client ID
According to Alibaba Cloud documentation, clientId can be customized. Generally, we directly use DeviceName in the triplet instead; timestamp can be left blank. In summary, mqttClientId: DS18B20|securemode=3,signmethod=hmacsha1|
2.4 Username
The deviceName in the username is replaced by the DeviceName in the triplet; productKey is replaced by the productKey in the triplet. In summary, mqttUsername: DS18B20&a1knXG89uwh
2.5 Password
Password Generation We can directly use the password tool password tool provided by Alibaba Cloud
3. Subscribe and publish messages
3.1 Subscription message
Uploading the data collected by the hardware to the cloud is called publishing a message; the cloud sending the data to the development board is called subscription.
Open the product, view the product details, and you can see that there are subscription and publishing interfaces.
#define SET_TOPIC "/sys/a1knXG89uwh/DS18B20/thing/service/property/set"//订阅
#define POST_TOPIC "/sys/a1knXG89uwh/DS18B20/thing/event/property/post"//发布
stat=MQTT_SubscribeTopic(SET_TOPIC,0,1);
if(stat)printf("订阅失败\r\n");
else printf("订阅成功\r\n");
3.2
The reporting format of the release message can be debugged online through the Alibaba Cloud platform, and data is uploaded according to the data format released by the cloud platform.
Implement data reporting in this way
if(cnt>=1000)
{
cnt=0;
temp=DS18B20_GetTemp()*0.0625;
sprintf(mqtt_message,"{\"method\":\"thing.event.property.post\",\"id\":\"0000000001\",\"params\":{\"RoomTemp\":%.2f},\"version\":\"1.0.0\"}",temp);//温度
MQTT_PublishData(POST_TOPIC,mqtt_message,0);
}
4. Send heartbeat packets
MQTT is a long-term connection. In order to keep the device online, it needs to send a heartbeat packet to the server at a fixed time. If it is not sent after the time expires, it will be forced to go offline.
if(time>=5000)
{
time=0;
MQTT_SentHeart();//发送心跳包
}
5. Main function
while(1)
{
stat=Esp8266_STA_TCPclinet_Init((u8 *)WIFI_NAME,(u8 *)WIFI_PASSWORD,(u8 *)SERVER_IP,SERVER_PORT);
if(stat==0)break;
Delay_Ms(500);
printf("stat=%d\r\n",stat);
}
printf("服务器连接成功\r\n");
while(1)
{
MQTT_Init();
stat=MQTT_Connect(ClientID,Username,Password);
if(stat==0)break;
Delay_Ms(500);
printf("正在连接....\r\n");
}
printf("阿里云连接成功\r\n");
stat=MQTT_SubscribeTopic(SET_TOPIC,0,1);
if(stat)printf("订阅失败\r\n");
else printf("订阅成功\r\n");
while(1)
{
if(usart3_flag)
{
usart3_cnt=0;
usart3_flag=0;
}
Delay_Ms(1);
time++;
cnt++;
if(time>=5000)
{
time=0;
MQTT_SentHeart();//发送心跳包
}
if(cnt>=1000)
{
cnt=0;
temp=DS18B20_GetTemp()*0.0625;
sprintf(mqtt_message,"{\"method\":\"thing.event.property.post\",\"id\":\"0000000001\",\" params\":{\"RoomTemp\":%.2f},\"version\":\"1.0.0\"}",temp);//温度
MQTT_PublishData(POST_TOPIC,mqtt_message,0);
}
}
6. Alibaba Cloud Web Design
Alibaba Cloud Server provides web and mobile interface development. We introduce the basic usage of web interface design.
6.1 Create a new web application 
6.2 Associated products
6.3 Create a new application
6.4 Design the interface
6.5. Configure the data source
6.6. Save and publish
6.7. Download the program, connect to Alibaba Cloud, and preview the web interface.
Summarize
MQTT is a publish/subscribe mode messaging protocol for client-server architecture. Its design idea is light, open, simple, and standardized, so it is easy to implement. It consumes less resources, and there are only 14 packets in the MQTT3.1 standard protocol. Each message is divided into three parts: fixed header, variable header and payload.
The 14 messages are as follows:
For a detailed explanation of each MQTT message, see the MQTT3.1 protocol.
Example project: https://download.csdn.net/download/weixin_44453694/16632625