This article is shared from China Mobile's OneOS WeChat public account " Action ~ Device-Cloud Integration Development Case Sharing ", author: Mr. Ruo.
Introduction to the development environment
1. Hardware : Wanco development board , a series of development boards based on STM32, NXP and other chips launched by China Mobile, which consists of core boards with different processing cores and Wanco backplanes. The backplane is universal. There are three core boards: STM32L475VGT6, STM32F401VET6 and NXPLPC55S69. Users can choose different core boards according to their needs.
2. Compilation tool chain : OneOS Cube is a command-line-based development tool for China Mobile's OneOS operating system, providing functions such as system configuration, project compilation and construction, and package contribution download.
Introduction
Use a temperature sensor AHT10 and a distance light sensor AP3216C of a Wan coupler development board (referred to as WAN coupler A) to collect sensor data, and upload the collected data to the OneNet platform through the wired network using the MQTT protocol.
On the one hand, we can view the uploaded data on the OneNet platform; on the other hand, we will download the data uploaded from Wanco A to OneNet using HTTP request on another Wanco development board (referred to as Wanco B). down, and at the same time it is displayed on the LCD display of Wandu B.
Implementation process
1. OneOS Cube configuration
Configure the following items through the OneOS Cube tool:
Table 1 Project configuration items
2. Code implementation
Overall design: (It is divided into 5 large modules in total)
Ⅰ: key_process
Ⅱ: lcd_process
Ⅲ: onenet_process
Ⅳ: sensor_process
Ⅴ: webapi_process
The functions of each module are divided as follows:
Table 2 code sub-module implementation
| module |
A brief description |
| key_process |
Register buttons and button callbacks, send events in button callbacks, and buttons are used to turn pages. For example, if you need to view the Sensor page, after pressing the button, the LCD_EVENT_SENSOR event will be sent |
| lcd_process |
In this module, a thread will be opened, which will always loop to detect whether there is a key event (such as LCD_EVENT_SENSOR) sent, and decide which page to draw and display according to different event types, and when switching to the corresponding page (such as Sensor) page), the data will be updated at a certain frequency, such as updating the sensor data on the Sensor page, and updating the calendar time data on the Calendar page |
| onenet_process |
After completing the OneNet MQTT subscription, start a thread that periodically reads data from a global variable that holds Sensor data, and uploads the sensor data to the OneNet data point topic through Publish |
| sensor_process |
Start a thread, periodically read local data from AHT10 and AP3216C sensors and store it in a global variable (mainly including temperature data, humidity data, distance data, light intensity data), the thread in onenet_process is from this global variable Read sensor data and upload it to OneNet |
|
webapi_process
|
Start a thread, periodically request the uploaded data points from OneNet through HTTP, download the sensor data (uploaded by other devices) on OneNet to the local, and then save it in a global variable, the thread in lcd_process will read these Data to refresh the LCD display (if the Sensor page is currently displayed) |
main function call:
Results display
1. View on OneNet
device online
2. Sensor data received on OneNet
3. Data display on two Wan coupler development boards
[Wanco development board A: The LCD displays the data collected by the sensor of Wanco development board B (B is first transmitted to OneNet, and then A is downloaded and displayed from OneNet. Note that the PS value shown in the above figure is very large, But the distance sensor in the lower right corner is not blocked (it should be very small if it is not blocked))]
[Wanco Development Board B: The data collected by the sensor of Wanco Development Board A is displayed on the LCD (A is first transmitted to OneNet, and then B is downloaded and displayed from OneNet. Note that the PS value shown in the above figure is very small, But the distance sensor in the lower right corner is blocked (the cover should be large))]
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