Design and Implementation of Remote Monitoring System for Smart Home

With the rapid development of the national economy and the continuous improvement of people's living standards, people's requirements for the comfort and safety of residential houses have also been upgraded to a higher level, while computer technology, network and information technology are also constantly developing, which makes the family Remote monitoring of intelligent systems has become a reality. The smart home remote monitoring system designed in this paper realizes the intelligent management of household appliances, real-time monitoring and automatic alarm function for the home environment.

The core part of the smart home remote monitoring system is an embedded Web server. The system integrates wired and wireless Web servers. Users can log in to the home web server using the PC of the office. After verifying by username and password, they can view and control. Household appliances. The system structure block diagram is shown in Figure 1.

The hardware circuit block diagram of this system is shown in Figure 2. It is mainly composed of ARM9 controller S3C2440, FLASH, SDRAM, power supply and reset module, touch screen display module, USB camera, Ethernet interface module, GPRS module, home appliance control, security control and so on.

2.1 ARM9 controller S3C2440

The ARM9 controller S3C2440 is a 16/32-bit RISC processor based on the ARM920T core. It has the advantages of powerful, cost-effective and low power consumption.

2.2 Appliance Control

This system proposes different solutions for the different levels of intelligence of home appliances. For traditional home equipment that requires manual control, such as light switches. The system adds auxiliary controllers (relays, etc.). Users can control the status of the processor GPIOn through Ethernet or SMS, and indirectly control the home equipment. For TVs, air conditioners, etc., which can be controlled by infrared rays, the system adopts The universal controller of the Ethernet interface is unified and remotely controlled; for the smart electrical equipment that has the network access function and supports the remote platform control, it can directly access the home Ethernet network.

2.3 Security Control

All detectors (smoke sensor, gas sensor, door sensor, etc.) and alarm devices used in the system are connected to the controller through GPIO to complete the alarm input and output. However, these input and output signals have a strong current and have a large interference to the system. Therefore, the TLP521 optical isolation chip and the relay are used to isolate the alarm input and output signals, thereby minimizing the influence of external signals on the system.

2.4 GPRS module

The GPRS module uses the MC35i GPRS MODEM from Siemens. When the S3C2440 controller receives the alarm signal, it controls the MC35i through the UART, and sends the pre-stored corresponding alarm information to the user's mobile phone through the GPRS network, and sends an alarm to the residential property center to make the user and the property department timely. Find dangerous situations and take effective measures to reduce economic losses.

2.5 Ethernet interface module

Since the S3C2440 does not have an integrated Ethernet control module itself, a matching DM9000 control chip is required to implement the Ethernet expansion interface. Connected between the DM9000 and RJ45 interfaces through the network isolation transformer HR601627. The connection diagram is shown in Figure 3. The network isolation transformer functions as a signal transmission and high voltage isolation to protect the system.

2.6 USB camera

The USB camera used in this system is ZC2301P from Vimicro. The video data stream formed by the video signal captured by the camera ZC301P is transmitted to the embedded web server through the internal bus. The user can directly view the video image on the web server by logging in to the network to monitor the situation in the home in real time.

The system control center is ARM9 controller, and its software design includes system software (embedded operating system, hardware device driver, embedded web server) design and application software (web design and CGI application) design.

3.1 Embedded operating system migration process on S3C2440

(1) Download the Linux kernel source linux-2.6.31 from the website. Tar. Bz2 and cross compiler arm920t-eabi. Tgz, this cross compiler is version 4.1.2, supports EABI, can improve the efficiency of compilation.

(2) Decompress the kernel source on the host machine to get linux-2.6.31, and extract the cross compiler to the specified directory.

(3) Modify the Makefile and related hardware files. Since the kernel is compiled according to the instructions of the Makefile, the Makefile organizes the relationships between the modules of the kernel and records the interconnections and dependencies between the modules. So, modify the Maldile file in the Linux2.6.31 root directory to specify the platform and cross compiler.

(4) Configure the kernel with the command # make menuconfig. When configuring the kernel, let it support EABI compilation.

(5) Execute the command # make zImage in the root directory of linux-2.6.31 to compile the kernel, and the generated kernel image file zImage is solidified into the corresponding memory of the system through the corresponding firmware to complete linux-2.6. The migration of the 31 kernel on the ARM microprocessor.