Brief Analysis of Intelligent Lighting Control System Based on ARM

After 3 months of continuous exploration, I finally completed the project practice content of the second phase of the 91arm Academy (the code in the video tutorial is not complete). I saved the relevant experience and code here for reference by myself and my classmates.

System Hardware:

Main control module: nanopi s2 (cortex-A9 quad-core s5p4418), 5v to 3.3v module, light sensor, sound sensor, 5v relay, breadboard and LED light, serial port to USB debugging interface, etc.

Wireless network module: tiny6410 (ARM11 Samsung S3C6410), infrared sensor, relay, breadboard and LED light

Let's look at the overall effect first. The main control program is znkg2018 and the network program is net_light

The main control and network end programs are as follows:

The web browser interface is as follows:

The main ideas of this project:

(1) The main control program znkg2018 (cross-compiled and ported to nanopi s2) contains four threads:

Thread 1: (used for inter-process communication) loops through shared memory and message queue data, and updates shared memory data to the main data structure memory in real time according to the message type of the message queue, or updates the main data structure memory to the shared memory;

Thread 2: (used to detect device online and offline) cyclically reads the data of the GPIO port of the development board connected to the 5V to 3.3V module. A high level indicates that the corresponding sensing device is connected to the system, and the level status of the GPIO port connected to the data line of the device can be read (the 5V to 3.3V module and the power line of the sensing device are connected together to achieve simultaneous plugging and unplugging, so that the plugging and unplugging of the corresponding sensing device can be detected through this thread);

Thread 3: (used to listen to the connection of network devices) This thread is the network server. First, it establishes a TCP data stream (socket~bind~listen ~ accetp) to loop and listen to the connection request of the network client. After receiving the request, it opens a new thread to communicate with the client, updates the network device status in the main data structure according to the client data, and sends corresponding commands to the network device according to the network device status in the main data structure. Network communication is based on the protocol, which is convenient for command classification and transmission verification.

Thread 4: (For lighting equipment switch control) This project has three small lights, two on the main control end and one on the network end. The switches are all controlled by relays, simulating 220V living room, study and office (remote) lights. Loop through the switch status of the lighting equipment in the main data structure, send write data commands to the corresponding relays to control the light switches. If the sensing device is bound to the lighting device, read the gpio port data of the sensing device and write the data to the gpio port of the relay. The network device only updates the network command status value, which is sent out by process three, and then processed by the network end program and controls its relay gpio, thereby controlling the corresponding light switch.

(2) The network client program net_light (cross-compiled and ported to tiny 6410) is just a main program:

The program connects to the network thread of the main control program on nanopi through the IP and port number, and updates the corresponding device status according to the network commands sent by the main control program.

(3) CGI program running on the boa server on nanopi:

After installing the boa server on nanopi, you can access the cgi program in nanopi through a browser. Put the index.html file in the www folder of boa, which is the welcome interface. The options in it are connected to different cgi programs. These programs open the shared memory and message queue managed by the main control program. By modifying the form and extracting the data in the form, updating the shared memory data, and notifying the main control device to update the shared memory or update the data in the shared memory to the main data structure memory through the message queue. After the main data structure memory is modified, the four threads of the main control device will take corresponding actions.

The editor uses the recommended source insight, which can automatically derive the declaration of variables and functions and their references to each other, making it easier to write and analyze programs (but the encoding format of the software I use is Ascill, not UTF-8, so it is garbled when compiled. It is OK to convert the encoding format with note pad ++)