CN112185272A - Wireless advertising board and working method thereof - Google Patents

Abstract

The embodiment of the invention discloses a wireless advertising board and a working method thereof, wherein the wireless advertising board comprises a main control chip and a display module, the display module is connected with the main control chip, the main control chip is wirelessly connected with an external communication device, the external communication device is used for accessing an HTTPS server which is pre-established on the main control chip after the wireless connection with the main control chip is established, and sending display content information input by a user on the HTTPS server to the main control chip, and the main control chip is used for controlling the display module to display after the acquired display content information is analyzed. The content display of the billboard is controlled in a wireless mode, the traditional mode that the display content is controlled through specific control software and a wired mode is abandoned, the system is simple and easy to operate, the display content is flexibly replaced, the control cost and the control complexity are low, and the application range is wide.

Description

Wireless advertising board and working method thereof

Technical Field

The embodiment of the invention relates to the technical field of billboards, in particular to a wireless billboard and a working method thereof.

Background

With the development of electronic technology, electronic advertisement display boards have slowly become a relatively common advertisement display terminal. With its development, it has been slowly becoming a very wide commercial and civil value, but some electronic display terminals commonly found on the market now need to solidify the displayed information in the system to be used in advance, the display content is not easy to change and replace at the later stage, and the equipment is used in the application place where the display content needs to be changed frequently, which is very troublesome and labor-consuming. In order to avoid the above situation, some display devices can select a method of directly connecting an electronic display board and a microcomputer by a wire to communicate, and the microcomputer is used for sending changed display contents, so that although the problem of changing the display advertisement contents in real time is temporarily solved, the wired connection mode increases the control cost and the complexity of control, limits the placement and use of the system in some occasions or time, and has certain limitations.

Disclosure of Invention

Therefore, the embodiment of the invention provides a wireless advertising board and a working method thereof, and aims to solve the problems that the display content is not easy to change and replace, the control cost and the control complexity are increased due to the wired connection of equipment and a microcomputer, and the use is limited in the conventional electronic advertising board.

In order to achieve the above object, the embodiments of the present invention provide the following technical solutions:

according to a first aspect of the embodiments of the present invention, a wireless advertising board is provided, where the wireless advertising board includes a main control chip and a display module, the display module is connected to the main control chip, the main control chip is wirelessly connected to an external communication device, the external communication device is configured to access an HTTPS server pre-established on the main control chip after establishing wireless connection with the main control chip, and send display content information input by a user on the HTTPS server to the main control chip, and the main control chip is configured to control the display module to display the display content information after analyzing the acquired display content information.

Further, the main control chip adopts an ESP32 module.

Further, the display module adopts a 64-by-16 LED dot matrix display screen.

Further, the external communication device comprises a mobile phone or a computer.

Further, the main control chip uses IO to establish a timing sequence and controls the display module to display corresponding content through the HUB08 interface.

According to a second aspect of the embodiments of the present invention, there is provided a method for operating a wireless billboard, the method including:

the main control chip initializes the GPIO to complete the HUB08 communication interface in a simulation mode, and after the HUB08 communication interface is completed, the display module starts to output default display content according to the input requirement;

network initialization, setting the main control chip to work in an AP mode, namely a routing mode, and allowing the access of external communication equipment with a browser;

an HTTPS server is established on the main control chip and used for establishing a communication webpage so that a user can log in the established webpage through a browser by using external communication equipment and input display content information in the webpage;

and the main control chip controls the obtained display content information to be displayed on a display module after analyzing the obtained display content information.

The embodiment of the invention has the following advantages:

the embodiment of the invention provides a wireless advertising board and a working method thereof, wherein the wireless advertising board comprises a main control chip and a display module, the display module is connected with the main control chip, the main control chip is wirelessly connected with an external communication device, the external communication device is used for accessing an HTTPS server pre-established on the main control chip after establishing wireless connection with the main control chip, and sending display content information input by a user on the HTTPS server to the main control chip, and the main control chip is used for controlling the display module to display after analyzing the acquired display content information. The content display of the billboard is controlled in a wireless mode, the traditional mode that the display content is controlled through specific control software and a wired mode is abandoned, the system is simple and easy to operate, the display content is flexibly replaced, the control cost and the control complexity are low, and the application range is wide.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below. It should be apparent that the drawings in the following description are merely exemplary, and that other embodiments can be derived from the drawings provided by those of ordinary skill in the art without inventive effort.

Fig. 1 is a schematic structural diagram of a wireless billboard provided in embodiment 1 of the present invention;

FIG. 2 is a schematic diagram of the HUB08 interface;

FIG. 3 is a schematic view of a dot matrix display;

FIG. 4 is a diagram of an index table and word stock lookup;

FIG. 5 is a table of the "Single factor app, no OTA" mode partition definition;

FIG. 6 is a schematic diagram showing a buffer region;

FIG. 7 is a schematic diagram of the shift left of the temporary storage area;

FIG. 8 is a diagram illustrating screen refresh;

fig. 9 is a schematic flow chart of a working method of a wireless billboard provided in embodiment 2 of the present invention.

Detailed Description

The present invention is described in terms of particular embodiments, other advantages and features of the invention will become apparent to those skilled in the art from the following disclosure, and it is to be understood that the described embodiments are merely exemplary of the invention and that it is not intended to limit the invention to the particular embodiments disclosed. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

Example 1

The embodiment of the invention provides a wireless advertising board, as shown in fig. 1, the wireless advertising board comprises a main control chip 100 and a display module 200, the display module 200 is connected with the main control chip 100, the main control chip 100 is wirelessly connected with an external communication device 300, the external communication device 300 is used for accessing an HTTPS server pre-established on the main control chip 100 after establishing wireless connection with the main control chip 100, and sending display content information input by a user on the HTTPS server to the main control chip 100, and the main control chip 100 is used for controlling the display module 200 to display after analyzing the acquired display content information.

In this embodiment, the main control chip 100 employs an ESP32 module. The display module 200 uses a 64 x 16 LED dot matrix display screen. The external communication device 300 includes a mobile phone or a computer. The main control chip 100 uses the IO setup sequence to control the display module 200 to display the corresponding content through the HUB08 interface.

Specifically, the ESP32 module is used as the core of the whole system design, and on one hand, it needs to establish an HTTPS server to receive the data to be displayed, and on the other hand, it needs to drive an LED dot matrix screen to display the corresponding advertisement content. In terms of HTTPS servers, ESP32 can only run lightweight Web servers, but only one input box and one submit button are needed for the HTTPS servers in this design, so the Web components of the ESP32 module are sufficient to fulfill the Web needs of the system. The Wi-Fi of ESP32 has three functions, and may be used as a site connection router, a router to receive connection of other sites, or both. In the design, if the Station mode is selected, the ESP32 is required to be connected to a route to provide HTTPS service, the ESP32 can directly establish a Wi-Fi hotspot in the AP mode, and then display information of a control billboard can be connected through a device which can use a browser. The ESP32 module is used as the core controller in this design because ESP32 can quickly and easily implement all functions from the Web server to the controller. The ESP32 module has the highest main frequency of 240M, the processing speed can basically meet the requirement when a simple webpage is requested, and the refreshing frequency of the lattice can be well controlled.

In the system, the HTTPS server is mainly used to make the ESP32 master control wirelessly connect to an arbitrary external device and display the received characters on the LED display board.

The ESP32 module provides the components of the HTTPS Server, so lightweight Web Server functions can run on the module. The component builds on esp HTTP server, and HTTPS is formed by HTTP plus secure socket layer protocol. The HTTPS server uses OpenSSL to provide encryption using the hook and function overlay method in conventional HTTP servers. The basic steps for building an API using an HTTP server component are as follows:

httpd _ start (): and creating an instance of the web server, configuring the instance of the web server according to specific requirements, allocating memory and resources, and returning a handle for creating the instance of the web server. The server uses two sockets after creation, one socket being used to listen for HTTP signals (TCP type) and the other to process control signals (UDP type), which are used alternately in the server's task cycle. By passing the parameter configuration structure of httpd to httpd _ start (), the priority of the task can be configured and the size of the stack can be defined at the time of creating the server instance. The TCP signal is parsed into a HTTP request, a processing program that has been registered by the user is called according to the URI (i.e. web address) of the request, and then response data is sent back in the processing program, where the response data may be a simple HTML code, and the browser renders a corresponding page according to the response data.

httpd _ stop (): and stopping the corresponding server according to the incoming handle, and releasing the memory and resources related to the server. This function is blocked from execution by first sending a stop signal to the server, which executes a command to stop the task and then waits for the task to be terminated. This task, accepted by the server during this time, will disconnect all connections that have been opened, delete all registered URI handlers, and clear all session context data as empty.

httpd _ register _ uri _ handler (): the program of URI handling is registered with an object of the httpd _ URI _ t struct type. This structure comprises the following members: uri name, request type, function pointer of esp _ err _ t _ handle (httpd _ req _ t _ req) type, user _ ctx pointer to user context data.

It should be noted that the Web server built by ESP32 may prompt security issues when accessed, because our security certificate is a self-signed security certificate, which is always present unless the security certificate is preloaded in the browser that is to log in to the Web page. Directly selecting trust on the browser after the security access restriction has been reached may also directly access the web page.

The display module 200 of the system is a 64 x 16 LED dot matrix display screen, which has 16 rows, each row consisting of 64 dots, each dot being capable of emitting light independently. This design adopts 64 × 16's LED dot matrix display screen module to have adopted the HUB08 interface, and this interface agreement stipulates that every point can send red light or yellow light respectively, also requires the green glow that can reddish simultaneously and yellow light is constituteed, and the LED dot matrix module that adopts can only send ruddiness in this design. The LED lattice module is essentially a simple circuit system consisting of a serial input and parallel output chip and a selector chip.

Common general interface forms of the LED dot matrix display screen are as follows: 04 interface, 08 interface and 12 interface, and 08 interface is selected and used in the system. In the design, the HUB08 interface is used for controlling the external display dot matrix, and ESP32 module hardware does not have the HUB08 interface protocol, so that the control is realized in an analog mode.

Fig. 2 is a schematic diagram of HUB08 interface. Pin ADDR _ A, ADDR _ B, ADDR _ C, ADDR _ D represents a row select signal; pins RED _1, RED _2, GREEN _1, and GREEN _2 indicate column signals, and data is input in series from these four pins; the ENABLE pin is a port for enabling signals; the CLOCK pin represents a CLOCK signal port; LATCH pin represents the port of the LATCH signal; the GND pin represents the port to ground. The pin ADDR _ A, ADDR _ B, ADDR _ C, ADDR _ D controls the row signal through 74595, and simultaneously controls the row signal and the column signal step by step to realize the scanning mode of the LED dot matrix display 1/16. The control of the row signal is realized by cascading two 3-8 decoder 74HC138 chips, and the cascade of the two chips substantially realizes the following specific functions:

when the data of the four IO ports ADDR _ D, ADDR _ C, ADDR _ B and ADDR _ A are 0000, the first line of the LED dot matrix display screen is selected; at this time, the data received by the 74HC595 is displayed in the first row, and each point of the first row of LEDs is controlled to be turned on or off according to the data output by the 74HC 595;

when the data of the four IO ports ADDR _ D, ADDR _ C, ADDR _ B and ADDR _ a are 0001, the second row of the LED dot-matrix display screen is selected, the specific form is the same as that described in the previous section, and the description is not repeated;

when the data of the four IO ports ADDR _ D, ADDR _ C, ADDR _ B, ADDR _ a is 0010, the third row of the LED dot matrix display screen is selected in the above form;

by analogy, when the data of the IO port ADDR _ D, ADDR _ C, ADDR _ B, ADDR _ a is 1111, the sixteenth row of the LED display screen is selected in the above form;

thus, we can control 16 lines of the LED display screen by four line signals ADDR _ A, ADDR _ B, ADDR _ C and ADDR _ D of 08 interfaces; the four column control signals of the 08 interface are all pulled down to be set to be 0, and then 16 high-low level signals from 0000 to 1111 are circularly input to the four row signals in sequence, so that the whole LED dot matrix display screen can be lightened. However, if a chinese character, a graphic or a special graphic of other characters is to be displayed on the LED dot matrix display screen, the desired display effect cannot be achieved by only controlling the row signals or the column signals, and the column signals for controlling the dot matrix also need to be selectively controlled.

When each column of the LED dot matrix display screen is driven, a 74HC595 chip is used, and the chip has the functions of converting input 8-bit serial data into 8-bit serial data and outputting the 8-bit serial data and also has the function of 8-bit data latching. For 64 × 32 LED dot matrix display screens used in the system, because there are 64 rows of LED display screens in total, it is necessary to cascade 8 74HC595 chips to achieve the desired row control, and the cascade connection of 8 74HC595 chips can expand 64-bit serial input signals to 64 bits and output signals, thereby achieving the effect of simultaneously controlling 64 × 32 signal points to display a complete picture.

The four IO ports RED _1, RED _2, GREEN _1 and GREEN _2 in the 08 interface mode are used for inputting 64-bit serial input data. Wherein RED _1 and GREEN _1 can be respectively used for controlling the selection of RED and GREEN signals of the upper half display screen (16 lines); RED _2 and GREEN _2 can be used to control the selection of the RED and GREEN signals, respectively, for the next half of the display (16 rows). Then, for a 64 × 32 bi-color LED dot-matrix display, a total of 4 × 8 — 32 chips of 74HC595 are required. Therefore, the LED display screen can display any Chinese characters, characters or other special graphs which are wanted by people.

The HUB08 essentially uses 74HC138 and 74HC595 chips to form a control circuit, and 74HC138 is used to control the selection of a row to be output, and then data is serially input into a serial-to-parallel circuit formed by 8 chips 74HC595, and the data is converted into parallel signals to be output to each control terminal of the row, thereby controlling the display of the row.

The basic timing sequence is:

in the first step, the EN pin is pulled down to 0.

And secondly, inputting 64-bit serial data, specifically pulling down the CLK pin to 0, setting the data pin to a corresponding level, and then pulling up the CLK pin to 1, so that one complete bit of data can be input into the system on the rising edge of the CLK.

And thirdly, setting the EN pin to be high level.

And fourthly, selecting an enabling row, pulling up the ADDR _ AT pin to be 1, and pulling down the ADDR _ AT pin to be 0.

And fifthly, pulling the EN pin low to 0.

As described above, repeating such a process 16 times (i.e., row selection goes one side from 0000-.

The character model is an array obtained by modeling characters according to the dot matrix display principle, as shown in fig. 3, to display a character "two" on a 16 × 16 dot matrix, data of each line is sequentially output according to the line order, such as the first line 000000000000, the fifth line 0001111111111000. Each character corresponds to a data block of 16 x 16 bits, and the data are combined into a look-up table according to a certain rule to form a word stock. Each character displayed on the LED dot matrix display screen needs to be composed of 16 × 16 dots, that is, at most 4 complete characters can be displayed by our display module at a time.

16×16÷8＝32(byte)

32 bytes are required to store one character, and the word stock is composed of 23940 Chinese characters, letters and symbols. The need to store this library

32×23940＝766080(byte)＝748(KB)

The program itself cannot support the stack definition of such a large data table calculated in the above formula, so we select a piece of FADDR _ Ash that is not used by both the boot program and the application program to write the piece of data directly into FADDR _ Ash, and then build an index table to find the corresponding position.

The index table stores the ANSI code corresponding to each character, i.e. one character occupies 3 bytes, so the size of the index table is

3×23940＝71820(byte)

However, there is no three-byte data type in C language, so the design uses 4-byte int type to store the index table

4×23940＝95760(byte)

The ESP32 module tested supported such a large stack definition as calculated by the above equation, so we defined this table directly in the program. And the character used by the character in FADDR _ Ash is located by searching the word bank table defined by the character bank table. The specific process is shown in fig. 4.

Firstly, the index corresponding to the character is searched from the index table, and then 32 bytes are taken out from the position of 0X210000 address plus the corresponding index multiplied by 32 in FADDR _ Ash, namely the dot matrix data corresponding to the character and to be displayed.

Regarding the selection of the FADDR _ Ash address, first to understand the division of the ESP32 module with respect to the FADDR _ Ash storage space, there are two stages of boot programs in the ESP32 module, where the first stage of boot program is already solidified in the internal ROM of ESP32, and it loads the second stage of boot program into RAM (IRAM & DRAM) from the 0x1000 offset address of FADDR _ Ash, and the second stage of boot program loads the partition table and the main program mirror into the memory from FADDR _ Ash, and the main program of the system contains RAM segment and read-only segment mapped by FADDR _ Ash cache. The partition table defines the storage space of FADDR _ Ash, that is, the data is stored from a certain address to a certain address, and the locations need to be avoided when storing the word library, so as not to affect the normal operation of the system function.

The location of the default partition is from the 0x8000 location of FADDR _ Ash. The partition table can be manually defined by itself, or a default partition table of the system can be selected, the system defaults to have two partition tables, after the characteristics of the system are considered, a mode of 'Single factor app, no OTA' is selected during design, and the basic definition of the partition table in the mode is shown in FIG. 5. It can be seen from the table that the last 0x10000 to 0x210000 locations of FADDR _ Ash store the application program, and the addresses are not reused later, so we store our word stock starting from 0x210000 locations.

The returned data of the web page is composed of character strings coded by ASSIC, the first five characters of the data are ' text ═ and the content after the equal sign is the returned submitted character strings, the coding of the character strings is that Chinese characters are coded by using Chinese characters ANSI, English characters are coded by ASSIC, each Chinese character is preceded by a '% ', namely:

％XX％XX％XXYYYY％XX％XX％XX

wherein X and Y both represent hexadecimal characters, nine characters such as% XX% XX% XX represent a Chinese character, two characters such as YY represent an ASSIC coded English character, so the character string is firstly subjected to data conversion, all characters are converted into a Chinese character ANSI coded format, the core of the conversion is that the ASSIC coded by the percentile is 25, every time a byte is 25, the Chinese character is encountered, 9 bytes from the byte are decoded into a Chinese character, if the byte is not 25, the Chinese character is determined to be an English character string, and two bytes from the byte are decoded into a character.

For convenience of data storage and display, three storage areas are established in the design, namely a recv _ buff storage area for storing received data, a buff storage area for performing an intermediate communication function, and a dispaly _ data storage area for final display, as shown in fig. 6.

Firstly, a server receives data, analyzes the data into Chinese character ANSI codes, finds out corresponding dot matrix display data through a lookup table, stores the corresponding dot matrix display data into recv _ buff, sets a receiving mark as received new data, then takes out the data into the buff after the fact task detects that the receiving data mark is set, and reads the data into dispaDDR _ Ay _ buff and displays the data on a screen when the next display is refreshed.

In order to display the entire content in a left-shift manner, a buffer area with one character storage size larger than the display data is defined. First, data of one character size is taken out from the well-defined dispaly _ buff and put at the end of the temporary storage area.

As shown in fig. 7 and 8, the memory model of the buffer is described, the buffer model is composed of 80 bits per line and 16 lines in total, the display data is extracted from the first bit of each line, each time the display is performed for a certain number of times, which causes the effect of persistence of vision, and then the pointer p _ data is moved to the right by one bit to start the next display. Until the display is finished after 16 times. The whole data of the temporary storage area is moved forward by the size of the memory occupied by one display character, and the next word of the dispDDR _ Ay _ buff is taken to the tail of the temporary storage area until all characters in the dispDDR _ Ay _ buff are displayed.

After the server is built, the server is connected to a Wi-Fi hotspot carried by an ESP32 module by using a device such as a mobile phone computer tablet, and then an IP address hppts://192.168.4. is input in a browser of an external device, and then a simple webpage which is built in the system design and transmits display contents can be directly accessed. Two more details are needed to note that ESP32 module defaults to 192.168.4.1 for its own IP address when using AP mode. Another is that the browser will prompt the site for more than a secure connection when the site is first accessed, which requires the browser to be set up to trust the site. The server returns a prompt message "out of the maximum range of the accepted character string" when the number of characters input is too much to exceed the capability to be processed.

Example 2

The embodiment 2 of the invention provides a working method of a wireless advertising board, which comprises the steps of firstly completing initialization of a hardware display circuit and construction of a Web server, triggering callback of a system by an HTTPS after data is received, processing the received data in the callback of the system, and then continuously refreshing information to be displayed by a system creation task. As shown in fig. 9, the specific method includes:

the main control chip initializes the GPIO to complete the HUB08 communication interface in a simulation mode, and after the HUB08 communication interface is completed, the display module starts to output default display content according to the input requirement;

network initialization, setting the main control chip to work in an AP mode, namely a routing mode, and allowing the access of external communication equipment with a browser;

an HTTPS server is established on the main control chip and used for establishing a communication webpage so that a user can log in the established webpage through a browser by using external communication equipment and input display content information in the webpage;

the main control chip controls the obtained display content information to be displayed on the display module after analyzing the obtained display content information.

Although the invention has been described in detail above with reference to a general description and specific examples, it will be apparent to one skilled in the art that modifications or improvements may be made thereto based on the invention. Accordingly, such modifications and improvements are intended to be within the scope of the invention as claimed.

Claims (6)

1. The wireless advertising board is characterized by comprising a main control chip and a display module, wherein the display module is connected with the main control chip, the main control chip is in wireless connection with external communication equipment, the external communication equipment is used for accessing an HTTPS server which is pre-established on the main control chip after the wireless connection is established with the main control chip, and sending display content information input by a user on the HTTPS server to the main control chip, and the main control chip is used for controlling the display module to display the acquired display content information after the display content information is analyzed.

2. The wireless advertising board according to claim 1, wherein the main control chip adopts an ESP32 module.

3. The wireless billboard of claim 1, wherein the display module employs a 64 x 16 LED dot matrix display screen.

4. A wireless billboard according to claim 1, in which the external communication device comprises a cell phone or a computer.

5. The wireless billboard of claim 1, wherein the main control chip controls the display module to display corresponding content through the HUB08 interface using IO setup sequence.

6. A method of operating a wireless billboard according to any of claims 1-5, comprising:

the main control chip initializes the GPIO to complete the HUB08 communication interface in a simulation mode, and after the HUB08 communication interface is completed, the display module starts to output default display content according to the input requirement;

network initialization, setting the main control chip to work in an AP mode, namely a routing mode, and allowing the access of external communication equipment with a browser;

an HTTPS server is established on the main control chip and used for establishing a communication webpage so that a user can log in the established webpage through a browser by using external communication equipment and input display content information in the webpage;

and the main control chip controls the obtained display content information to be displayed on a display module after analyzing the obtained display content information.

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