Design of intelligent disinfection robot control system for livestock breeding based on ARM7

1 Overall design
The livestock breeding intelligent disinfection robot control system consists of three parts: robot intelligent control module, monitoring module, and wireless network communication module. The working process is to send control command codes to the remote robot through a mobile phone or microcomputer client connected to the Internet through a wireless network, and the transmission signal is encrypted by the sender using a dongle. When the signal is sent to the receiving terminal via the Internet, the intelligent disinfection robot network module transmits the received instructions to the processor, and the processor instructs the drive module to drive the intelligent disinfection robot to perform actions. While moving, the monitoring module transmits the collected images to the client through the wireless Internet. Its overall structure is shown in Figure 1.

1.1 Intelligent control module
This module is the core part of the intelligent disinfection robot. It adopts an embedded system design, which can run and process data accurately and efficiently. The controller communicates data with the external network through the network component WIFI or GPRS. Users can use the home broadband network or mobile phone text messages to realize remote control of the module. At the same time, infrared wireless keyboards and digital LCD screens can also be used for local control to provide local human-computer communication interfaces.
1.2 Network module
The wireless network communication module of the intelligent disinfection robot is an important part of the communication signal transmission of the intelligent disinfection robot. It uses WIFI or GPRS modules to realize communication. The communication medium is a home wireless router or mobile network GPRS.
1.3 Monitoring module
The monitoring module of the intelligent disinfection robot realizes all-round monitoring by driving the servo through a single-chip microcomputer. The video signal is collected by the camera, and the PAL signal of the video is transmitted to the processor after signal conversion, and then transmitted to the client in real time through the wireless network. The control of the camera is connected to the intelligent control module, and the movement of the camera is controlled by the control module.
1.4 Drive module
The drive module of the intelligent disinfection robot is driven by an encodable DC motor. When the processor receives the command from the client, the processor processes the signal of the drive module, thereby realizing the full range of movement of the intelligent disinfection robot.

2 System Hardware Design
This paper uses the PHILIPS single-chip 32-bit ARM microcontroller LPC2138 as the processor of the controller, which is responsible for data communication with WIFI, GPRS wireless communication module, monitoring module, data storage, keyboard, infrared, display and other modules, and for collecting and processing the signals sent by the wireless network client.
2.1 Control core module
The ARM peripheral circuit includes power keyboard display, SD card, SDRAM and expansion interface connected to various auxiliary modules. The ARM processor is embedded with 512k FLASH and 32k readable and writable RAM. The SDRAM chip in the circuit is hy57v25641, with a storage capacity of 16M. It is used as the memory required for system operation, providing a reliable operating space for the acquisition of operating system signals and data processing. The extended interfaces are serial port and USB interface. The serial port is used to download programs and communicate with the GPRS module, and the USB interface is used to connect to WIFI to access the wireless Internet. The LCD display screen is mainly used in conjunction with the keyboard to complete the local human-computer interaction interface. The LCD has 240×320 pixels and 65k colors, and the driver chip is ili9325. The keyboard uses a PS2 interface to facilitate the use of a computer keyboard, and works with the LCD to complete the local human-computer information exchange. The serial port communicates with the host computer through MAX232, and the download of the auxiliary microcontroller is downloaded through ISP, supporting online debugging.
2.2 Peripheral network module
WIFI and GPRS modules are used to realize the communication connection between the processor and the client. The WIFI module uses the wf8000-u USB WIFI module. The GPRS module uses the BENQ M22A module. The peripheral circuits of each communication module mainly include: power supply part, work indication and data connection expansion port.
2.2.1 TTL level
The connection between the GPRS module and the processor is through serial communication. The level between the module and the processor is TTL level, so it can be directly connected without level conversion.
2.2.2 MAX232 conversion level
Due to the different level definitions between the programming and debugging controller computer and the processor, MAX232 is used for level conversion, and its peripheral circuit mainly includes the power supply part.
The MAX232 level conversion module is used to process the RS232 signal on the computer side to obtain the TTL level, and the communication circuit between the computer, processor and GPRS module is shown in Figure 2.

2.2.3 GPRS Peripheral Network Module
The 15th pin of the GPRS module must be kept at a low level for 3 seconds to start the module. This paper uses software to simulate the low-level GPRS module startup. The shutdown circuit also keeps the pin at a low level for 3 seconds. The circuit is shown in Figure 3.

Pin 35 of the GPRS module is a working status indicator interface, and the status indications are: on for 1s and off for 1s to start the search signal; on for 1s and off for 2s to indicate a normal signal; and continuously on for data input or output. Its working principle diagram is shown in Figure 4(a). Figure 4(b) is a schematic diagram of the SIM card connection of the GPRS module.

The working level of the GPRS module serial port is TTL level, so the connection between the GPRS module and the control core processor can be directly connected. However, considering the debugging of the module and the burning of the program, a transfer switch is used at the connection between the GPRS module and the processor. In this way, the communication from the computer to the processor and the communication from the GPRS module to the computer are completed. The schematic diagram of the communication circuit connection of the GPRS module, processor, and computer is shown in Figure 5.

3 Monitoring module
The monitoring module uses a common high-definition video camera with a resolution of 1024×768. The video is transmitted in PAL mode and processed by the processor, and the image is transmitted to the client through the wireless Internet. Its circuit diagram is shown in Figure 6(a). The various directions of the camera are realized by the microcontroller driving the servo, and the servo drive circuit is shown in Figure 6(b).

4 Driver module
The driver module uses the L298N driver chip, which has high power and can directly use 12V power supply. A single chip can control two DC motors. This article uses two L298N chips to realize the directional movement of the intelligent disinfection robot. The circuit is shown in Figure 7.

5 Power module
The power supply part uses a 12V DC lithium battery with a power of 10W. Each module is powered separately. The voltage regulator uses 7805. Since GPRS has particularly high requirements for power supply, a separate LM2941S is used to power it. The
wf8000 WIFI module is a wireless network module produced by Huawei specifically for embedded systems. The module complies with the 802.11b standard and the chip uses prism3.0. The schematic diagram is shown in Figure 8.

6 Conclusion
This control system can realize remote control of the robot and real-time monitoring of the working environment. Combined with the disinfection mechanical device, it can realize intelligent remote control disinfection work in special working environments. In some places with poor environments such as animal husbandry, it can replace human work to achieve more functions and bring convenience to breeding work.