A remote encrypted transmission system and method for 3D printing

Abstract

The present invention relates to a remote encrypted transmission system and method for 3D printing, the system includes a transmission control circuit board, the transmission control circuit board is connected to a server and a printing terminal respectively, the server is connected to a mobile terminal, a single-chip microcomputer, a wireless transmission module, an EEPROM memory, an SD card, a first latch and a second latch are arranged on the transmission control circuit board, the wireless transmission module is connected to the server to receive encrypted files from the server; the wireless transmission module is connected to the single-chip microcomputer, the single-chip microcomputer is connected to the EEPROM memory, and a key for decoding encrypted files is stored in the EEPROM memory; the single-chip microcomputer controls the first latch to realize the connection and disconnection between the single-chip microcomputer and the SD card; the single-chip microcomputer controls the second latch to realize the connection and disconnection between the printing terminal and the SD card. Compared with the prior art, the present invention can reliably achieve the purpose of efficient transmission and secure transmission.

Description

Technical Field

[0001] The present invention relates to the technical field of 3D printing, and in particular to a remote encrypted transmission system and method for 3D printing. Background Art

[0002] 3D printing technology appeared in the mid-1990s. It is actually the latest rapid prototyping device using technologies such as photocuring and paper lamination. It works in the same principle as ordinary printing. The printer is filled with "printing materials" such as liquid or powder. After connecting to the computer, the "printing materials" are stacked layer by layer through computer control, and finally the blueprint on the computer is turned into a physical object. 3D printing is often used to make models in the fields of mold manufacturing and industrial design, and then gradually used for the direct manufacturing of some products. There are already parts printed using this technology. This technology has applications in jewelry, footwear, industrial design, architecture, engineering and construction (AEC), automobiles, aerospace, dental and medical industries, education, geographic information systems, civil engineering, firearms and other fields.

[0003] As a new technology, 3D printing is more conducive to product prototype development and customized design for customers due to the special printing materials. This technology is suitable for the R&D and manufacturing of samples and the production of small and medium-sized batches of castings, which saves the long mold opening time and high mold opening costs. In addition, 3D printing technology has no shape requirements, so designers can design castings according to the best solution. Most of the 3D printers on the market currently use USB flash drives or data cables to transmit file data. This transmission method may not only bring security threats due to devices such as USB flash drives, but also is not conducive to accurate and fast transmission of print files when deploying large quantities of printers in the future. Summary of the invention

[0004] The purpose of the present invention is to overcome the defects of the above-mentioned prior art and provide a remote encrypted transmission system and method for 3D printing to achieve the purpose of safe and efficient transmission of print file data.

[0005] The objective of the present invention can be achieved through the following technical scheme: a remote encrypted transmission system for 3D printing, comprising a transmission control circuit board, the transmission control circuit board is respectively connected to a server and a printing terminal, the server is connected to a mobile terminal, a single-chip microcomputer, a wireless transmission module, an EEPROM memory, an SD card, a first latch and a second latch are arranged on the transmission control circuit board, the wireless transmission module is connected to the server to receive an encrypted file from the server; the wireless transmission module is connected to the single-chip microcomputer, the single-chip microcomputer is connected to the EEPROM memory, and a key for decoding the encrypted file is stored in the EEPROM memory; the single-chip microcomputer controls the first latch to realize the connection and disconnection between the single-chip microcomputer and the SD card; the single-chip microcomputer controls the second latch to realize the connection and disconnection between the printing terminal and the SD card.

[0006] Furthermore, the wireless transmission module is connected to the server via TCP protocol.

[0007] Furthermore, the SD card is connected to the single-chip microcomputer or the printing terminal via an SPI interface.

[0008] Furthermore, the EEPROM memory is connected to the single chip microcomputer via an IIC interface.

[0009] Furthermore, the single chip microcomputer is connected to the wireless transmission module via a DMA controller.

[0010] Furthermore, a display module for displaying the current file transfer status is provided on the transmission control circuit board, and the display module is connected to the single-chip microcomputer.

[0011] Furthermore, the server is connected to a printing terminal to send a printing request to the printing terminal.

[0012] Furthermore, the wireless transmission module is specifically an ESP8266 chip.

[0013] Furthermore, the first latch and the second latch are both 74hc573 latches.

[0014] Furthermore, the single chip microcomputer is specifically a stm32f103c8t6 chip.

[0015] A remote encrypted transmission method for 3D printing, comprising the following steps:

[0016] S1. The user inputs the file to be printed on the mobile terminal, and the mobile terminal uploads the file to the server;

[0017] S2. The server encrypts the file to obtain an encrypted file, and transmits the encrypted file to the wireless transmission module;

[0018] S3, the single chip microcomputer obtains the encrypted file from the wireless transmission module and the key from the EEPROM memory, and decodes the encrypted file according to the key;

[0019] S4, the single chip microcomputer controls the first latch to connect the single chip microcomputer with the SD card, and then the single chip microcomputer transfers the decoded file to the SD card for storage;

[0020] S5. The single chip microcomputer controls the second latch to connect the printing terminal to the SD card, and the printing terminal reads the stored file from the SD card.

[0021] Compared with the prior art, the present invention has the following advantages:

[0022] 1. The present invention connects a transmission control circuit board to a server and a printing terminal respectively, arranges a single-chip microcomputer, a wireless transmission module, an EEPROM memory, an SD card, a first latch and a second latch on the transmission control circuit board, stores a key in the EEPROM memory, connects to the server through the wireless transmission module, and connects the single-chip microcomputer to the wireless transmission module and the EEPROM memory respectively. The server obtains files from a mobile terminal and performs encryption processing. After the single-chip microcomputer obtains the encrypted file through the wireless transmission module, it obtains the key from the EEPROM memory for decoding processing, and then stores the decoded file in the SD card. Finally, the printing terminal reads the decoded file from the SD card, thereby reliably achieving the purpose of wireless, efficient and secure transmission of file data.

[0023] 2. The present invention sets a first latch and a second latch, and uses a single chip microcomputer to control the first latch and the second latch respectively, so as to correspondingly realize the connection and disconnection between the single chip microcomputer and the SD card or the connection and disconnection between the printing terminal and the SD card, thereby avoiding the problem of file transmission confusion.

[0024] 3. The present invention adopts a DMA controller to connect the single-chip microcomputer with the wireless transmission module, and transmits data based on DMA to reduce the data processing pressure of the single-chip microcomputer. In addition, the data transmission between the SD card and the single-chip microcomputer or the printing terminal is realized through the SPI interface, which can effectively improve the transmission rate, reduce the transmission time, and further improve the efficiency of file data transmission. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 It is a schematic diagram of the system structure of the present invention;

[0026] Figure 2 Schematic diagram of the transmission system structure in the embodiment;

[0027] Figure 3 This is a circuit diagram of the SD card and latch control part in the embodiment;

[0028] Figure 4 This is a circuit diagram of a wireless transmission module in an embodiment;

[0029] Figure 5 It is a circuit diagram of an EEPROM memory in an embodiment;

[0030] Figure 6 This is a circuit diagram of the power supply part in the embodiment;

[0031] Figure 7 It is a circuit diagram of the single chip microcomputer in the embodiment;

[0032] Figure 8 It is a circuit diagram of a display module in the embodiment;

[0033] Fig. 9 It is a schematic diagram of the method process of the present invention;

[0034] Explanation of the marks in the figure: 1. Transmission control circuit board, 2. Server, 3. Printing terminal, 4. Mobile terminal, 11. Single chip microcomputer, 12. Wireless transmission module, 13. EEPROM memory, 14. SD card, 15. First latch, 16. Second latch, 17. Display module. DETAILED DESCRIPTION

[0035] The present invention is described in detail below with reference to the accompanying drawings and specific embodiments.

[0036] Example

[0037] like Figure 1 As shown, a remote encrypted transmission system for 3D printing includes a transmission control circuit board 1, which is connected to a server 2 and a printing terminal 3 respectively, and the server 2 is connected to a mobile terminal 4. A single-chip microcomputer 11, a wireless transmission module 12, an EEPROM memory 13, an SD card 14, a first latch 15 and a second latch 16 are arranged on the transmission control circuit board 1, wherein the wireless transmission module 12 is connected to the server 2 to receive an encrypted file from the server 2; the wireless transmission module 12 is connected to the single-chip microcomputer 11, and the single-chip microcomputer 11 It is connected to the EEPROM memory 13, which stores a key for decoding encrypted files; the single-chip computer 11 controls the first latch 15 to realize the connection and disconnection between the single-chip computer 11 and the SD card 14; the single-chip computer 11 controls the second latch 16 to realize the connection and disconnection between the printing terminal 3 and the SD card 14. In addition, in actual applications, the transmission control circuit board can also be provided with a display module 17 for displaying the current file transmission status. The display module 17 is connected to the single-chip computer 11, and the present embodiment uses an OLED display screen.

[0038] In this embodiment, Figure 2As shown, the single chip microcomputer 11 uses the stm32f103c8t6 chip, the wireless transmission module 12 uses the ESP8266 chip, and the first latch 15 and the second latch 16 both use the 74hc573 latch ( Figure 2 HC1 and HC2 in it). Among them, the ESP8266 chip is connected to the server through the TCP protocol, the SD card is connected to the stm32f103c8t6 chip or the printing terminal through the SPI interface, the EEPROM memory is connected to the stm32f103c8t6 chip through the IIC interface, the stm32f103c8t6 chip is connected to the ESP8266 chip through the DMA controller, and the server is connected to the printing terminal to send an HTTP printing request to the printing terminal based on the WEB page.

[0039] Specifically, this embodiment applies the above technical solution, and the hardware circuit part on the transmission control circuit board can be divided into stm32f103c8t6 single-chip microcomputer, OLED display part, ESP8266 wireless transmission module, SD card storage part, EEPROM storage part and latch transmission control part. The ESP8266 used in this hardware platform performs remote wireless transmission, uses ESP8266 as a client, connects to a remote server for TCP connection, connects to AP at the data link layer and obtains an IP address, connects to the connection port of the target server at the network layer and calls back a function to allocate space and set a protocol, and in order to facilitate file transmission, sets the wireless transmission module to transparent transmission mode, and turns off the transparent transmission mode when the transmission is completed. Since most wireless transmission modules use serial port protocols, the transmission speed is slow. For the baud rate of 115200bps, the transmission speed is only 10kb / s. There is a proportional relationship between the size of the 3D printing file and the size of the model. The model size ranges from a few MB to hundreds of MB. It takes a lot of time to use serial port transmission. The present invention uses the SPI transmission protocol instead. The transmission is carried out through the SPI interface. The transmission rate can reach 120kb / s-300kb / s, and the transmission time is greatly reduced. At the same time, DMA transmission is used at the embedded control end to reduce the processing pressure of the embedded chip. Since the transmission protocol at the 3D printer end is relatively complex and not universal, but basically uses SD cards for file storage, the present invention directly connects the connection part of the SD card, controls the connection state of the relevant pins through a latch, and switches the transmission pin to the transmission control end when the print file needs to be transmitted, and switches to the printer when the transmission is completed and printing is required. At the same time, the encryption protocol needs to save the key. The present invention writes the key into the EEPROM storage chip and reads it when the key is needed.

[0040] Figure 3The figure shows the circuit diagram of the SD card and latch control part, wherein the SD card is connected to the single-chip microcomputer or the printing terminal through the hardware SPI, so that the single-chip microcomputer or the printing terminal can read and write the SD card, and the latch control part is provided with HC1 and HC2, wherein HC1 corresponds to the connection on-off control between the single-chip microcomputer and the SD card, and HC2 corresponds to the connection on-off control between the printing terminal and the SD card;

[0041] Figure 4 This is a partial circuit diagram of the wireless transmission module. The wireless transmission module realizes the sending and receiving of file data under the control of the single-chip microcomputer;

[0042] Figure 5 This is the circuit diagram of the EEPROM memory part. The EEPROM memory is connected to the single-chip microcomputer through the IIC bus and is responsible for storing the key used to decode the communication encrypted file;

[0043] Figure 6 For the power supply circuit diagram, it is mainly responsible for stepping down the voltage of the input circuit board ( Figure 6 BOOT chip in the system) to provide power to the microcontroller and other functional modules;

[0044] Figure 7 This is the circuit diagram of the single-chip microcomputer, including the Y1 crystal oscillator circuit, the Y2 crystal oscillator circuit and the reset circuit ( Figure 7 The RESET button circuit in the figure), where the Y1 crystal oscillator circuit provides the program execution cycle, the Y2 crystal oscillator circuit provides the internal clock cycle, and the reset circuit is responsible for the hardware reset of the microcontroller;

[0045] Figure 8 This is the OLED display circuit diagram. The OLED mainly displays the current file receiving status, current receiving progress and other information.

[0046] The above remote encryption transmission system is applied in practice. The specific transmission process is as follows: Fig. 9 As shown, the following steps are included:

[0047] S1. The user inputs the file to be printed on the mobile terminal, and the mobile terminal uploads the file to the server;

[0048] S2. The server encrypts the file to obtain an encrypted file, and transmits the encrypted file to the wireless transmission module;

[0049] S3, the single chip microcomputer obtains the encrypted file from the wireless transmission module and the key from the EEPROM memory, and decodes the encrypted file according to the key;

[0050] S4, the single chip microcomputer controls the first latch to connect the single chip microcomputer with the SD card, and then the single chip microcomputer transfers the decoded file to the SD card for storage;

[0051] S5. The single chip microcomputer controls the second latch to connect the printing terminal to the SD card, and the printing terminal reads the stored file from the SD card.

[0052] In specific applications, the present invention adopts STM32 as the main control chip, which can be compatible with power consumption and more peripherals. The OLED display part adopts the IIC transmission interface to update the display data, and displays in real time whether the transmission request, transmission progress and remaining transmission time are received. The key control part is used to restart the transmission setting, and the EEPROM adopts the IIC interface to write and read data, which is used to save the local key to handle the decoding problem after transmission. The latch control part is used to control the switching connection pin of the SD card pin through two latch chips. The file transfer process is that the server first sends a connection request to the transmission control board, the transmission control board is ready to receive the file, and the ESP8266 is switched to the transparent transmission mode, and the latch is controlled to switch the connection pin to the transmission control board. The server encrypts the file and transmits it. The transmission control board first saves the file after receiving it. After the complete transmission is completed, the key saved by the EEPROM is read and the file is decoded and saved again. To save a file, the SPI protocol is used to transfer data through the STM32 DMA controller. The Fatfs file system is deployed on the application layer to perform file read and write management, save and delete operations. The top layer of Fatfs is the application layer. By using the file management system to integrate the internal structure and the complex FAT protocol, you only need to call the Fatfs application interface functions, such as f_open, f_read, f_write and f_close APIs, to perform operations such as reading and writing files. The middle layer Fatfs module implements the FAT file read and write protocol. The underlying part that needs to write the transplant code is the underlying interface provided by the Fatfs module, which includes the storage media read and write interface and the real-time clock that provides the file creation and modification time.

[0053] The underlying storage interface communication uses the SPI interface. In SPI mode, the SD card can respond to different commands with R1-R7. Since the SPI mode is used, the SD card must first enter the SPI mode. When the SD card receives the reset command (CMD0), CS is at a valid level (low level), and the SPI mode is enabled. However, before sending CMD0, >74 clocks must be sent. This is because the SD card has a power supply voltage rise time of about 64 CLKs. The remaining 10 CLKs are used for SD card synchronization. Only then can the CMD0 operation be started to complete the initialization of the SD card.

[0054] The file transfer process uses the DES encryption algorithm to encrypt files in the server. DES is a block encryption algorithm that processes fixed-length data segments each time, called blocks. The size of a DES block is 64 bits. If the length of the encrypted data is not a multiple of 64 bits, the bits can be filled according to certain specific rules. In essence, the security of DES relies on false appearances, which in cryptographic terms is based on the principle of "chaos and diffusion". The purpose of chaos is to hide the relationship between any plaintext and ciphertext or key, while the purpose of diffusion is to make the valid bits in the plaintext and the key together form as many ciphertexts as possible. The combination of the two makes the security relatively high. The DES algorithm specifically encrypts the plaintext by performing a series of permutations and substitutions on it. The key to the process is to get the function of 16 subkeys from a given initial key. To encrypt a set of plaintext, each subkey is applied to the data in order (1-16) with a series of bit operations, once for each subkey, and repeated 16 times in total. Each iteration is called a round. To decrypt the ciphertext, the same steps can be used, except that the subkeys are processed in the reverse order (16-1).

[0055] After the transmission is completed, the transmission control board sends a transmission end signal to the server, and the server closes the file transfer connection. After receiving the file, the microcontroller reads the key from the EEPROM through the IIC interface, and the decryption program on the microcontroller decrypts the file. The transmission control board controls the latch to switch the connection pin to the printer end. The printer end can read the file in the SD card. The server initiates a file query request, and the printer end determines whether the file exists and returns information. After receiving the information, the server makes a file print request. After receiving the print request, the printer reads the file from the SD card and starts printing. This design changes the previous situation where printers can only rely on transmission lines and USB flash drives and other devices. The remote file transmission method makes printing more convenient and also facilitates unified management of batch printers. The transmission data is encrypted during the transmission process, which effectively avoids security issues in the transmission process.

Claims

1. A remote encrypted transmission method for 3D printing, applied to a remote encrypted transmission system for 3D printing, characterized in that: The remote encrypted transmission system comprises a transmission control circuit board (1), wherein the transmission control circuit board (1) is connected to a server (2) and a printing terminal (3), respectively, and the server (2) is connected to a mobile terminal (4). The transmission control circuit board (1) is provided with a single chip microcomputer (11), a wireless transmission module (12), an EEPROM memory (13), an SD card (14), a first latch (15), and a second latch (16). The wireless transmission module (12) is connected to the server (2) to receive data from the server (2). ); the wireless transmission module (12) is connected to the single-chip microcomputer (11), the single-chip microcomputer (11) is connected to the EEPROM memory (13), and the EEPROM memory (13) stores a key for decoding the encrypted file; the single-chip microcomputer (11) controls the first latch (15) to realize the connection and disconnection between the single-chip microcomputer (11) and the SD card (14); the single-chip microcomputer (11) controls the second latch (16) to realize the connection and disconnection between the printing terminal (3) and the SD card (14); The remote encrypted transmission method comprises the following steps: S1. The user enters the file to be printed on the mobile terminal, and the mobile terminal uploads the file to the server; S2. The server encrypts the file to obtain an encrypted file, and transmits the encrypted file to the wireless transmission module; S3, the single chip microcomputer obtains the encrypted file from the wireless transmission module and the key from the EEPROM memory, and decodes the encrypted file according to the key; S4, the single chip microcomputer controls the first latch to connect the single chip microcomputer to the SD card, and then the single chip microcomputer transfers the decoded file to the SD card for storage; S5. The single chip microcomputer controls the second latch to connect the printing terminal to the SD card, and the printing terminal reads the stored file from the SD card.

2. A remote encrypted transmission method for 3D printing according to claim 1, characterized in that: The wireless transmission module (12) is connected to the server (2) via the TCP protocol.

3. A remote encrypted transmission method for 3D printing according to claim 1, characterized in that: The SD card (14) is connected to the single chip microcomputer (11) or the printing terminal (3) via the SPI interface.

4. A remote encrypted transmission method for 3D printing according to claim 1, characterized in that: The EEPROM memory (13) is connected to the single chip microcomputer (11) via an IIC interface.

5. The remote encrypted transmission method for 3D printing according to claim 1, characterized in that: The single chip microcomputer (11) is connected to the wireless transmission module (12) via a DMA controller.

6. The remote encrypted transmission method for 3D printing according to claim 1, characterized in that: The transmission control circuit board (1) is provided with a display module (17) for displaying the current file transmission status, and the display module (17) is connected to the single chip computer (11).

7. The remote encrypted transmission method for 3D printing according to claim 1, characterized in that: The server (2) is connected to the printing terminal (3) to send a printing request to the printing terminal (3).

8. The remote encrypted transmission method for 3D printing according to claim 1, characterized in that: The wireless transmission module (12) is specifically an ESP8266 chip, and the single chip computer (11) is specifically an stm32f103c8t6 chip.

9. The remote encrypted transmission method for 3D printing according to claim 1, characterized in that: The first latch (15) and the second latch (16) are both 74hc573 latches.

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