CN104317255A - Internet-of-things-based intelligent household control system - Google Patents

Abstract

The invention discloses a smart home control system based on the Internet of Things. The control system includes an Internet of Things communication module based on the RS-485 bus, which is responsible for the communication tasks between the RS-485 bus access device and the ARM processor; the Ethernet remote The control module is responsible for receiving the control commands sent by the user from the Internet, and the user realizes remote control of the smart home; the alarm and control module based on GPRS is responsible for receiving various alarm information of the security alarm system in the smart home and sending fault reports to the user's mobile phone ; The human-computer interaction module is used for information transmission between users; the device interface part is used for connecting various devices. The present invention utilizes multi-interfaces to unify and centrally control all electrical equipment in the home, and utilizes an intelligent control terminal to realize overall control.

Description

IoT-based smart home control system

technical field

The invention relates to the field of the Internet of Things, in particular to a smart home control system based on the Internet of Things.

Background technique

The development of automation technology and information technology has promoted the continuous development of smart home. It is also constantly changing people's work and life, and people's demand for improving the quality of life is increasing day by day. At present, the smart home control system on the market already has a relatively complete system and functions. Based on consumers' needs for smart homes, the main functions should include household device control, smart lighting control, security alarms, access control, infrared monitoring, and remote services. With the development of the smart home industry, more new things will gradually become an important part of the smart home control system. The smart home control system has changed people's way of life, greatly changed people's quality of life, and allowed people to enjoy a novel, fun and fashionable life. From people's awareness of smart homes to their needs, people's lives in the future may be inseparable from smart homes. The smart home control system will connect different home smart devices together, and build a modern smart system with complete functions, safety, reliability and intelligence through various bus technologies. It can mobilize people's subjective initiative, promote the coordination between people and the living environment, and make people yearn more freely to control the living environment. From the perspective of consumers, the smart home control system should have the control functions of various types of household equipment interconnection, various remote monitoring system functions, reliable system alarm functions and harmonious interaction functions.

The interconnected control of smart home equipment is a basic feature of the smart home control system. In terms of smart home, decentralized control and decentralized management are often used for home appliances, computers, light source control, Internet and smart devices. Its obvious disadvantage is that various household devices cannot be connected to the Internet, and users cannot control them uniformly. In this case, it is of great significance to develop a set of devices with multi-electrical appliance interfaces, which can unify the networking of all electrical equipment in the home and centrally control them. Through the intelligent control terminal, all kinds of household electrical equipment can be freely controlled whether at home or in other places, and it cannot be difficult to control because of the variety of equipment types. Even though the control parameters of household appliances are diverse, there are some common features. For example, all devices have control switches so that you can use binary 0s and 1s to represent the two states. For the gear control of certain devices, the brightness adjustment of lights, the temperature control of air conditioners, etc., this article controls these devices by adding control parameters and adding control fields in the control command. Therefore, for the electrical control of smart home, it is important to consider the problem of control parameters.

Contents of the invention

In order to solve the above problems, the present invention provides a smart home control system based on the Internet of Things, which utilizes multiple interfaces to unify and centrally control all electrical equipment in the home, and utilizes an intelligent control terminal to realize overall control.

In order to achieve the above object, the technical scheme that the present invention takes is:

A smart home control system based on the Internet of Things, the control system includes:

The IoT communication module based on the RS-485 bus is responsible for the communication task between the RS-485 bus access device and the ARM processor; the ARM processor determines the life cycle of the access device through a detection circuit. At the same time, orderly poll the running status of household appliances on the bus, and monitor or control the running of the equipment by sending a query or control command. And receive feedback from any home device. The main task categories include: access device detection tasks, bus reception tasks, and bus transmission tasks.

The Ethernet remote control module is responsible for receiving the control commands sent by the user from the Internet, and the user realizes the remote control of the smart home; when using it, we must first verify whether the user has the authority to control the home system, if the system receives the correct user control command , the ARM processor will directly send control commands to the corresponding smart home appliances through the RS-485 bus for control. The main tasks include sending tasks of Ethernet data transmission and receiving tasks of Ethernet data.

The GPRS-based alarm and control module is responsible for receiving various alarm information from the security alarm system in the smart home and sending fault reports to the user's mobile phone;

In addition, users can remotely query and control the running status of home equipment. Its remote control function is the same as the Ethernet control function. When the system receives the user control short message, the ARM processor will directly send control commands to the corresponding smart home appliances for control through the RS-485 bus. The main tasks include short message sending task and short message receiving task.

The human-computer interaction module is used for information transmission with users. It must pass through the human-computer interaction module as a bridge to complete. Users can set system parameters, including working mode setting, alarm number permission setting and so on. The main tasks include LCD menu display tasks, key processing tasks and voice prompt tasks.

The device interface part is used to connect various devices.

Wherein, the device interface part includes:

Common electrical interface, used to connect household appliances;

Security equipment interface, used to connect security equipment;

Monitoring equipment interface, used to connect monitoring equipment;

Wherein, the man-machine interchange part includes a liquid crystal display screen for displaying menus and prompting user information and operation instructions;

Receive a control button module for controlling the system;

Real-time clock for displaying accurate time and as an alarm clock;

Memory, used to save system parameters and system status information;

The voice prompt module is used for voice alarm.

Wherein, the core processor that described system uses is LPC2378 ARM processor.

The beneficial effects of the present invention are as follows: use multiple interfaces to unify and centrally control all electrical equipment in the home, and use an intelligent control terminal to realize overall control.

Description of drawings

FIG. 1 is a frame diagram of a smart home control system based on the Internet of Things according to an embodiment of the present invention.

FIG. 2 is a summary diagram of the peripherals of the LPC237 in the smart home control system based on the Internet of Things according to the embodiment of the present invention.

FIG. 3 is a structural diagram of the RS-485 network in the smart home control system based on the Internet of Things according to the embodiment of the present invention.

FIG. 4 is a structural diagram of the Ethernet in the smart home control system based on the Internet of Things according to the embodiment of the present invention.

FIG. 5 is a schematic diagram of the interface of the MAX232 chip in the smart home control system based on the Internet of Things according to the embodiment of the present invention.

Fig. 6 is a structural diagram of the human-computer interaction part in the smart home control system based on the Internet of Things according to the embodiment of the present invention.

Fig. 7 is a workflow of the master polling the slave in the smart home control system based on the Internet of Things according to the embodiment of the present invention.

Fig. 8 is a working flowchart of slave machine response in the smart home control system based on the Internet of Things according to the embodiment of the present invention.

FIG. 9 is a flow chart of receiving data by DP83848I in the smart home control system based on the Internet of Things according to the embodiment of the present invention.

Fig. 10 is a flow chart of sending data by DP83848I in the smart home control system based on the Internet of Things according to the embodiment of the present invention.

FIG. 11 is a flow chart of the short message task of the GPRS alarm control module in the smart home control system based on the Internet of Things according to the embodiment of the present invention.

Detailed ways

In order to make the objects and advantages of the present invention clearer, the present invention will be further described in detail below in conjunction with the examples. It should be understood that the specific embodiments described here are only used to explain the present invention, not to limit the present invention.

As shown in Figure 1, the embodiment of the present invention provides a smart home control system based on the Internet of Things, the control system includes

The IoT communication module based on the RS-485 bus is responsible for the communication task between the RS-485 bus access device and the ARM processor; the ARM processor determines the life cycle of the access device through a detection circuit. At the same time, orderly poll the running status of household appliances on the bus, and monitor or control the running of the equipment by sending a query or control command. And receive feedback from any home device. The main task categories include: access device detection tasks, bus reception tasks, and bus transmission tasks.

The Ethernet remote control module is responsible for receiving the control commands sent by the user from the Internet, and the user realizes the remote control of the smart home; when using it, we must first verify whether the user has the authority to control the home system, if the system receives the correct user control command , the ARM processor will directly send control commands to the corresponding smart home appliances through the RS-485 bus for control. The main tasks include sending tasks of Ethernet data transmission and receiving tasks of Ethernet data.

The GPRS-based alarm and control module is responsible for receiving various alarm information from the security alarm system in the smart home and sending fault reports to the user's mobile phone;

In addition, users can remotely query and control the running status of home equipment. Its remote control function is the same as the Ethernet control function. When the system receives the user control short message, the ARM processor will directly send control commands to the corresponding smart home appliances for control through the RS-485 bus. The main tasks include short message sending task and short message receiving task.

The human-computer interaction module is used for information transmission with users.

It must pass through the human-computer interaction module as a bridge to complete. Users can set system parameters, including working mode setting, alarm number permission setting and so on. The main tasks include LCD menu display tasks, key processing tasks and voice prompt tasks.

The device interface part includes:

Common electrical interface, used to connect household appliances;

Security equipment interface, used to connect security equipment;

Monitoring equipment interface, used to connect monitoring equipment;

As shown in Figure 6, the human-machine interchangeable part includes a liquid crystal display for displaying menus and prompting user information and operating instructions;

Receive a control button module for controlling the system;

Real-time clock for displaying accurate time and as an alarm clock;

Memory, used to save system parameters and system status information;

The voice prompt module is used for voice alarm.

Among them, the human-computer interaction module is an important part of the control system design. The human-computer interaction is responsible for providing a friendly interactive interface and functions to make people and machines live in harmony. Through a good human-computer interaction interface design, it can increase user dependency. As an integral part of the smart home control system, the human-computer interaction terminal is a platform for information interaction between people and equipment, through which the intelligent control system transmits information with users. Its hardware components should include LCD display, information control buttons, real-time clock, information storage, status indicator lights, and voice prompts. Realize the communication between the intelligent system and the user through intelligent key query, device status display and voice prompt. As shown in Figure 6, the structure of the human-computer interaction part uses the DS1302 chip as the real-time clock chip. The DS1302 chip is a high-performance, low-power real-time clock launched by DALLAS Corporation of the United States. With RAM data storage, date and time can be set. DS1302 chip interface circuit is simple, cheap, easy to use and easy to operate. The real-time clock module can display accurate time, and the user can set the alarm clock function.

The memory module is a non-volatile external memory module used to save system parameters and system status information, such as the alarm center number set by the user. The system uses FM24C64A serial electrically erasable read-only memory (EEPROM). This module can be connected in series with high scalability and is widely used in the fields of low voltage and low power consumption.

The receiving control button module is an important input interface part of the human-computer interaction design, and the user can control the system through the keyboard. The system is provided with 16 keys, including numbers 0-9, menu (function) key, confirmation key and four direction keys.

The main part of the human-computer interaction design of the liquid crystal display and menu display processing is used to display the menu and prompt the user for information and operating instructions. The liquid crystal display provides great convenience for the user, and the user can know the operating status of each household appliance at any time, as well as the current fault information. Users can implement a full range of monitoring and control operations by setting menu functions. Therefore, the menu display and the corresponding information processing module are also the modules that require the most workload. The liquid crystal display used in this system is OCM1264, with its own Chinese and English fonts, which is convenient for software development. Through key operation, users can set the system, check and control various household appliances.

The channel through which the module system communicates directly with the user. Through the setting function of the control system, the home environment variables are set, and the system will provide corresponding background music. If there is a dangerous situation at home, the voice prompts the alarm module. At the same time, the control system calls the remote alarm system to notify the user, and the user performs corresponding processing according to the alarm information. The system adopts the HMA-TTS speech synthesis module, which is a modular product and is transplanted into the embedded system of the Chinese speech synthesis software SMA-TTS. Small size, good synthetic sound quality, low power consumption, easy to use, no external auxiliary circuits. It can be controlled by UART serial port with power supply and speaker. The synthesis control interface can also be customized according to the user's needs to meet the requirements of smart home applications for speech synthesis.

As shown in Figure 2, the core processor used by the system is the LPC2378 ARM processor. The LPC2378 ARM processor produced by Philips is a suitable choice. The cost-effective LPC2378 has rich interfaces and is very suitable for network protocol conversion and applications with multiple device interfaces. It is based on 32-bit real-time simulation ARM7TDMI-S core structure, and has high-speed embedded 512KB flash memory and 58KB SRAM, with in-system programming (ISP) and application programming (IAP) capabilities. The chip has 4 UARTs, 3 I2Cs, 3 SPI/SSP serial interfaces, 10/100M Ethernet MAC interface with DMA, and more than 104 general-purpose IO interfaces.

As shown in Figure 3, the electrical characteristic of the RS-485 bus is multi-point differential data transmission, the communication interface allows multi-point two-way communication on a simple pair of twisted pairs, it has noise suppression, high data transmission rate and reliable data transmission and other characteristics. Relatively simple hardware interface, only one of the household devices on the bus is in the sending state at the same time, while the other devices are in the receiving state. In a serial communication network composed of multiple single-chip microcomputers, a master-slave architecture is used: the slave machine can only send commands or data passively, and when it needs to actively send data and commands, it is controlled by the host computer.

The RS-485 bus interface part designed in this paper is directly connected to the serial port 0 of the embedded processor, and communicates through two pins of TXD RXD and a level shifter. In parallel transmission mode, a termination resistor needs to be connected to the RS-485 transmission line. Different functions can be realized when two different wiring methods are used. If the wiring method of four lines is adopted, only one-to-many data communication can be realized. And use the two-wire wiring method to achieve multi-point two-way communication. The embedded processor in this article is the master device, while other connected home devices are said to be slave devices.

If household equipment needs to be connected to the RS-485 network, it must be realized through a microcontroller, a detection circuit and a current conditioning circuit. A pin of the microcontroller is connected to the output of RS-485, and the change of the access state of the smart electrical appliance is determined by detecting the jump of the pin level. The function of the signal conditioning circuit is to isolate the output level of the smart appliance and the electrical signal in the bus. Using the SN75176 chip can convert the serial interface in the single-chip microcomputer into an RS-485 interface, so that the serial communication of various access household appliances and embedded development boards can be realized.

The system of the invention uses the 10/100M Ethernet module with DMA in the ARM processor LPC2378, which greatly improves the sending and receiving rate of data packets, improves the real-time performance of sending and receiving data by the system, and reduces the workload of the microprocessor. The RMI interface chip of the Ethernet module in the ARM processor is connected with the Ethernet PHY chip (DP83848I).

As shown in Figure 4, the block diagram of the Ethernet module consists of the following parts:

Host register module. It is used to set the Ethernet working mode, and the working status of the Ethernet can be understood by reading the status register.

The bus interface is an interface connecting the AHB bus and the Ethernet DMA. The module can read SRAM in time to realize reading and writing descriptors, as well as buffers for sending and receiving data.

DMA sends and receives data. Responsible for the information transmission of the data buffer and the data bus. The sending DMA manager writes the transfer status and descriptor of the transfer data into the memory; the module can resend the data and handle abnormal termination, and control the sending of data. The function of the receiving manager is to detect information, filter specific data frames, and store valid data.

RMII is responsible for real-time data transmission with DP83848.

The purpose of the GPRS-based remote alarm network design is mainly to improve the security of the smart home control system. Therefore, the remote alarm needs to have high real-time and high reliability.

The remote alarm network is divided into three parts: on-site collection terminal, monitoring center and GPRS service center. On-site collection terminals include household appliances connected to the RS-485 bus, and various sensors (such as temperature sensors, humidity sensors, etc.), which collect and transmit family safety information data to the monitoring center in real time. The monitoring center processes the received data and analyzes whether there are alarms and fault information. If a status data that is not working properly is received, the remote alarm system will send an alarm message to the user through the GPRS service center to ensure the safety of the user's property.

The system GPRS module adopts the SIM300CZ module produced by SIMCOM Company. SIM300CZ module can work in tri-band/quad-band GSM/GPRS equipment, providing more than 10 levels of multi-slot and level 4 encoding capabilities. It is compact in structure, dual-in-line board-to-board connector, compact in structure, and can meet the strict requirements of various industrial applications on module size; embedded with powerful TCP/IP protocol stack, low power consumption; using enhanced AT The communication protocol of the command set realizes the high-speed transmission of language, short message and GPRS data. The combination of remote alarm network and RS-485 bus network is designed to function as remote alarm and control.

The key points of the remote alarm control part of GPRS in this paper are: ①Use the embedded system to send and receive short messages; Immediately turn on the automatic fire extinguishing device; ③ The image information captured by the camera is sent to the wireless communication module through the serial port, and then sent to the user through GPRS.

As shown in Figure 5, the control system and serial communication module. By using relays, household electrical equipment is turned on and off. The control terminal of the device must be directly controlled by the I/O pins of the ARM controller. The SIM300 communication module connected to the ARM processor requires level shifting. The MAX232 is the most commonly used level conversion chip.

Plug and Play Communication Protocol for Home Appliances

The smart home appliances are coded according to the unified device number UDS. The length of the UDS is 3 bytes. Different smart home appliances have different electrical device numbers. The system home network device address is divided into 2 bytes, namely the network device ID. The first byte represents the first-level address, and the 2 bits are used to distinguish the type of device; the second byte represents the second-level address. In order to facilitate the access control terminal to query and control each device, each electrical appliance is connected to the control terminal. The control terminal assigns the ID of the Internet of Things to each device automatically or manually, so that each home device has a unique number to achieve the purpose of remote access to the device. The encoding method is: when a new device is connected to the intelligent control terminal, assign a unified device serial number to the reserved home network device address, so that the conversion between the IoT device ID and the device serial number UDS can be realized. Considering that the reserved bits of the first-level address of the home network are bit2 to bit7, the second-level address can be used to indicate the serial number of the household appliance, and the device type can be distinguished through the first-level address code. UDS structure definition: bit0-bit7 indicates the device number, bit8-bit20 indicates the manufacturer number, and bit21-bit23 indicates the version number.

RS-485 bus master-slave communication protocol

The data frame format of the master-slave communication in the bus is defined in this way. The data frame consists of fields such as frame header, device address, command (function), data length, data, checksum and frame tail. The format is 1 byte for the frame header, 1 byte for the device address, 1 byte for the command (function), 1 byte for the data length, N bytes for the data, and 1 byte for the checksum and the end of the frame. Occupies 1 byte.

The system adopts a reliable connection method. Every time the master asks a slave, it uses a "handshake" mechanism. The master first sends a handshake signal to the slave, and if the slave is online, the slave sends a response signal back to the master. Thereby a reliable connection is established between the master and the slave, and data can then be exchanged securely. After exchanging data, ask the next slave in turn. Only when the master asks a slave, the slave will give a reply. This mechanism can avoid the disruption of the data transmission of the entire bus network caused by out-of-order data communication

The frame format of the data frame sent by the master to the slave is as follows:

frame header address Order Data length data checksum end of frame S Addr 0x51 0x00 0x00 *

The frame format of the data frame that the slave replies to the master is as follows:

frame header address Order Data length data checksum end of frame S Addr 0x61 0x00 0x00 *

The data frame sent by the master to the slave is mainly divided into the following two types according to the purpose:

Query type: The master detects whether the slave is online by sending this type of data frame. If the slave is online, the host can obtain the current operating parameters of the slave.

Control type: By sending this type of data frame, the host can set the gear position of the household appliance and control the switch of the household appliance. As shown in Table 3.1, the data frames sent by the master to the slave include query data frames and control data frames. At the same time, when the master sends a command frame to the slave, if the slave is online, the slave needs to give a response. As shown in Table 3.2, the content of the data frame that the slave replies to the master.

Table 3.1 Data frame sent by master to slave

Table 3.2 The data frame that the slave replies to the master

In the design of GPRS alarm and control tasks, the short message service function of GPRS is used to transmit text and digital information. The key to the design is how to realize the sending and receiving of short messages in the embedded system. The editing process of short messages is described in detail as follows.

According to the content of the short message, the short message is divided into a Chinese short message and a non-Chinese short message based on the PDU format. The content of Chinese short messages based on PDU format contains Chinese characters. For non-Chinese short messages without Chinese character content, it is necessary to use the encoding of pure English short messages. The GPRS module integrates the AT command set, and realizes the module parameter setting by controlling the AT command set, and realizes the communication between the ARM processor and the wireless module. To use the short message function in an embedded system, you need to know the format of the message.

(1) Communication protocol between ARM processor and GPRS module

The character string formats for sending short messages include: SCA, PDUType, MR, DA, PID, DCS, VP, UDL and UD. The character string formats for receiving short messages include: SCA, PDUType, OA, PID, DCS, SCTS, UDL and UD. SCA is a short message service center address, including short message service center address byte length len, type 1 byte short message center, and 11 short message service center address byte address. The length is the length of the short message service center address (91)+(683108200505f0), even if the number of digits of the phone number is short of "F" in the backfill, and then flip the number of parity bits; in the type of short message center address, 91 is the most used, add a "+" sign before the number. pdutype is the type of PDU, occupying one byte. He is an information reference, which is 00 under normal circumstances. DA is the recipient's address, Oa is the sender's address, and their format is the same as the short message service center address SCA. For the standard case of short messages, the PID signing agreement is simply PID00. DCS is a data coding scheme for short message content. Divided into 7-bit code, 8-bit code and USC2 coded short message content code. Semi-English (non-Chinese short message) short message 7bit encoding, and Chinese short message content requires USC2 encoding. VP is valid information. The transaction timestamp service center covers an area of more than seven groups. The length of UDL user data, the number usually represents the encoded string of the content of the short message.

Send and receive Chinese short messages based on PDU mode. In the USC2 encoding standard, the encoding of Chinese characters occupies 2 bytes, so when encoding short messages mixed with Chinese and English, it is necessary to use the short message encoding method based on PDU mode. The Chinese encoding process of the short message will be described in detail below.

The content of sending a short message is defined by the user, for example, the content is "smart home", the address number of the short message center is set in the system in advance, assuming it is 8613843155031, and the other party's number is assumed to be 8613543421121. The specific encoding process is shown in Table 3.3.

Table 3.3 Editing process of short message content

Therefore, the encoded content of the message, combined with the PDU string should be: 08 00 08 66 7A 80 FD5B B6 5C 45 08 91 68 31 08 11 00 0D 91 68 5129 22 50 20 02 05 F0 92F2 00. According to the regulations of PDU encoding, UCS2 encoding adopts 16-byte encoding. The embedded system in this article does not have the API function of UCS2 code, it can only be obtained by the look-up table method. The content of the short message to be sent is pre-coded, and the edited coded string is stored in the system memory.

The receiving and sending of the short message is similar to the encoding of the content of the short message.

The following are commonly used AT commands:

AT+CMGF set the format of the short message, 0 is set to PDU format, 1 is set to TEXT format

AT+CSCA Set the service center number of the short message

AT+CNMI will display the new short message to the TE terminal

AT+CMGL query the short message in the module

AT+CMGR read the short message of the specified number

AT+CMGD delete the short message with the specified number

AT+CMGS send short message

AT+CSQ to get signal strength

(2) Communication protocol between smart home control system and users

The communication between the smart home control system and the user needs a corresponding communication protocol to achieve mutual communication, so it is necessary to formulate a corresponding short message communication protocol between the user and the system.

The short message communication protocol formulated in this paper is divided into three types of short messages according to the content of short messages: alarm short messages, query short messages and control short messages.

The alarm short message is a short message sent by the smart home control terminal to a specific user. The user's mobile phone number needs to be authorized in advance and stored in the external memory of the system. When the smart home control system detects that a certain home device fails or the family is in danger, it will immediately send specific alarm information to the user. The format of alarm short messages is shown in Table 3.4.

Table 3.4 Alarm short message

Query short messages are sent directly to the smart home control terminal by authorized users, and are used to check whether the operating status of a specific electrical appliance in the smart home is normal, and to obtain the operating parameters of the electrical appliance. The format of query short messages is shown in Table 3.5.

Table 3.5 Query Short Messages

The control short message is to realize the remote control of the smart device by the user, including setting the operating gear of a specific smart electrical appliance and controlling the operating status of the electrical appliance. The format of control short messages is shown in Table 3.6.

Table 3.6 Control short messages

It should be noted that when the system receives user information, it must first determine whether the user number has been authorized. If the user number is not authorized, the system will delete the information to prevent spam harassment.

RS-485 bus program design

The host (embedded microprocessor) polls whether each smart device connected to the RS-485 bus is in normal operation, and the detection circuit determines which device ID is in the online state, and then obtains an access smart device buffer Address[255] , if the address line 3 is a smart device, the address [3] of the buffer is set to 1, and all values of the device address are 0, indicating that the smart device is removed. The master is always polling the slaves to detect the working status of each slave in real time. When the system receives an inquiry or control command from the user, the host establishes a handshake mechanism with the slave, and then sends an inquiry or control command to the slave for processing. The command sent by the master to the slave will not wait for the reply from the slave in a loop. If no reply from the slave is obtained for three consecutive times, the system considers that the device has been removed, and modifies the corresponding value in the buffer of the device at the same time. If bus communication is disabled, the master stops polling. The workflow of the host polling the slave is shown in Figure 8.

The slave (each connected smart home appliance) is always in the data receiving state. When receiving the command frame from the host, it first determines whether the data in the command frame is correct, and then establishes a handshake mechanism with the host if it is correct. At the same time, analyze whether the frame is a control command or a query command. If it is a control command, then the slave will feedback the information after the command is executed. If the query command, the slave sends an online reply. The workflow of the slave response is shown in Figure 9.

Ethernet Remote Monitoring Program Design

The system uses Ethernet smart home network monitoring equipment, the Ethernet module is connected to the ARM processor, and the processor is used as the Ethernet server. In order to realize that the smart home control terminal can automatically feed back the query results and control results to the user, and receive the user's remote query request and control command, it is necessary to program the Ethernet module, mainly including the initialization of the Ethernet controller, sending and receiving data operation.

(1) Initialize the dp83848i Ethernet module

The main work is to initialize the reset of the Ethernet module, the initialization of PHY and MAC, and the sending and receiving of data.

(2) The microprocessor receives user data through the Ethernet module

The embedded ARM microprocessor realizes the data exchange through the I/O port 4 and the Ethernet communication module. The receiving microprocessor data is automatically stored in the receiving buffer rx_databuffer, and the program analyzes the data read into the buffer, understands the type of user instruction, and then makes corresponding processing.

(3) Send the response data to the user through the Ethernet module microprocessor

Sending data to the user is similar to receiving user data. The Ethernet module packs the data frame into a data packet and stores it in the sending buffer TX_DataBuffer, and then uses the command register to send the data packet. After sending successfully, judge whether the data packet is accurate or not by detecting the corresponding bit of the status register status. If the packet fails, the system should resend the packet. At the same time, the system should be able to detect if the transmit channel is disabled, enable the transmit channel using the TxEnable bit setting in the command register. The process of receiving data by DP83848I is shown in Figure 10.

When DP83848I sends data, it first checks whether the sending descriptor array is full, if not, writes the data to be sent to the sending buffer pointed to by the sending descriptor and sets the control word of the sending descriptor to update RxProduceIndex, by setting the TxEnable in the control register bit enables DMA to start sending packets. I When the data transmission is completed, an interrupt is triggered; if the data transmission fails, the program executes the retransmission operation. If the data has not been sent for three consecutive times, the data packet will be discarded and the system will be notified of the failure to send, and the system will be required to reset the Ethernet module. The process of sending data by DP83848I is shown in Figure 10.

GPRS Short Message Program Design

The GPRS module integrates the AT command set, and realizes the module parameter setting by controlling the AT command set, and realizes the communication between the ARM processor and the wireless module. In the process of GPRS remote data communication, it is mainly through the serial port communication, using the UART1 serial port to indirectly realize the communication between the user's short message and the processing center of the smart home control system. To achieve the purpose of "direct" control of smart home devices. In the embedded system, the short message sending process is: set the wireless communication module as the working mode under the PDU mode through the AT command AT+CMGF=0, and use the CMGS command to send the short message command to the GPRS wireless communication module. Number of bytes After unloading the CMGS command, wait for the corresponding information of the GPRS module ">" indicates that the wireless module is waiting for the user to send the user combination string (the data string after the user content is encoded), and the final command to send the short message is to use sixteen Hexadecimal "0x1A" to notify the wireless communication module to send the short message.

The receiving process of the short message: complete receiving the short message through the UART1 interrupt, as long as the embedded microprocessor serial port detects the received string information, it can enter the serial port interrupt. The arrival of a new message is determined by matching the string "+CMTI:"SM",N". Wherein N represents the number of arrival of the new short message. Read the short message with the specified number by command CMGR, if there is this short message on the SIM card, the GPRS module will return the detailed information of this short message to serial port 1. Due to the signal of the GPRS wireless module or the busy data communication, many short messages may also be received. At this time, the unread short messages can be listed through the CMGL command, so that the smart home control system can process these short messages. However, the mailbox of the GPRS wireless module is limited after all, and short messages need to be deleted regularly. Therefore, after reading and processing this short message, you can use the CMGD command to delete this short message. The short message task workflow of the GPRS alarm control module is shown in Figure 11.

External Interrupt

The external interrupt of the smart home control system is the interrupt request sent by the external device of the embedded system, and the key interrupt is mainly in the system. The user realizes the setting of system parameters and environment mode through external interrupt processing. The control system in this article judges by removing the jitter of the key first, and then detecting the level change of the I/O pin. When the external key interrupt signal is detected, the smart home control system executes the external interrupt service program and responds to the user's key processing. And notify the LcdRsk task and the RS-485 task to change the menu and control the smart device respectively.

The above is only a preferred embodiment of the present invention, it should be pointed out that for those of ordinary skill in the art, without departing from the principle of the present invention, some improvements and modifications can also be made, and these improvements and modifications should also be It is regarded as the protection scope of the present invention.

Claims (4)

1. A smart home control system based on the Internet of Things, characterized in that the control system includes: The IoT communication module based on the RS-485 bus is responsible for the communication tasks between the RS-485 bus access device and the ARM processor; The Ethernet remote control module is responsible for receiving the control commands sent by the user from the Internet, and the user realizes the remote control of the smart home; The GPRS-based alarm and control module is responsible for receiving various alarm information from the security alarm system in the smart home and sending fault reports to the user's mobile phone; Human-computer interaction module, used for information transmission between users; The device interface part is used to connect various devices. the 2. The smart home control system based on the Internet of Things according to claim 1, wherein the device interface part comprises: Common electrical interface, used to connect household appliances; Security equipment interface, used to connect security equipment; Monitoring equipment interface, used to connect monitoring equipment. the 3. The smart home control system based on the Internet of Things according to claim 1, characterized in that: The man-machine interchange part includes a liquid crystal display for displaying menus and prompting user information and operating instructions; Receive control button module for controlling the system; Real-time clock, used to display accurate time and used as an alarm clock; Memory, used to save system parameters and system status information; The voice prompt module is used for voice alarm. the 4. The smart home control system based on the Internet of Things according to claim 1, wherein the core processor used by the system is an LPC2378 ARM processor. the