**1. Introduction**
With the continuous improvement in living standards, people are now enjoying a more convenient and comfortable lifestyle. As a result, the awareness of home security has significantly increased. People are now more concerned about electrical safety, gas safety, anti-theft systems, child and elderly care, and other aspects of home protection. In response to these growing needs, smart home systems have gradually become a part of daily life. These systems integrate computers, embedded systems, and communication network technologies to combine various subsystems related to home life—such as lighting, security, and appliances—into a seamless and efficient system. This integration not only enhances comfort but also improves the overall safety of the home environment.
**2. System Functions**
The system is designed for everyday users who want to monitor their homes remotely. It offers three main functions:
(1) **Home Security**: If the indoor temperature exceeds a set threshold or if smoke levels are high, or if any unusual activity is detected in a specific area, the system will alert the user through multiple methods, such as sending text messages to a mobile device or triggering an alarm signal. Additionally, if someone enters the wrong password three times consecutively at the access control, the system automatically sends a message to the homeowner and sounds an alarm inside the house.
(2) **Remote Monitoring**: Temperature, smoke, and human body sensors provide real-time data displayed on an LCD screen, allowing users to check the current status of their home at any time. They can also access this information online through a web server or use a universal remote control to check temperature, smoke levels, and movement in specific areas.
(3) **Access Control**: When a guest visits, they can interact with the system via the LCD screen to enter a guest interface. This allows them to send messages to the homeowner, view the calendar, or access help documents, making the process more convenient and secure.
**3. System Design**
The system uses the mini4020 development board as the main platform, with a 51 microcontroller acting as the auxiliary control unit. Additional hardware components include a motor module, GPRS module, LCD 1602 display, and a universal remote control. Real-time data collection is done using temperature, smoke, and human body pyroelectric sensors. Communication between the mini4020 and the microcontroller is facilitated by the ZT-TR43U wireless interface.
**3.1 Hardware Design**
As shown in Figure 1, the system consists of two main parts: the mini4020 main console and the 51 microcontroller-based slave console. Expansion modules such as the GPRS module (used for sending alarm signals), the motor module (to simulate smart door opening), and the sensor modules (temperature, smoke, and human body pyroelectric) support the system's functionality. The 51 microcontroller is placed indoors to transmit sensor data wirelessly to the main control station, while the mini4020 is located outdoors at the access control point to process data in real time and trigger alarms when necessary.
**3.2 Software Design**
(1) **Main Program**: Upon startup, the system first checks peripheral devices and loads drivers before booting the operating system. Once initialization is complete, the monitoring system is loaded as a background process. It continuously reads serial port data, and if an abnormal condition is detected, it triggers an alarm. A flowchart of the startup process is shown in Figure 2.
(2) **Temperature, Smoke, and Human Body Pyroelectric Alarm**: These alarms follow a similar process, as illustrated in Figure 3. Sensors collect data indoors, which is then transmitted wirelessly to the mini4020 at the access control. If an issue is detected, the system activates the GPRS module to send an alert.
**3.3 LCD Display Interface**
The LCD interface includes two sections: one for the homeowner and one for guests. Clicking on the owner’s interface leads to a password entry screen that uses a random algorithm to change the keyboard layout. After entering the correct password, users can view real-time sensor data and modify their password. Guests can access a different interface where they can press a doorbell button to alert the homeowner or send a text message if no one answers.
**3.4 PC User Interface**
Users can log into their computers at any time to monitor the home environment. They can view real-time data from temperature, smoke, and motion sensors, as well as access control information. The PC interface provides a comprehensive overview of the system's status, as shown in Figures 10 and 11.
**4. Conclusion**
The system was first tested on a virtual machine, debugged, and then programmed onto the development board. The final product is cost-effective, with a total cost of around 1,000 RMB, and offers good performance. It makes full use of common communication tools and integrates GPRS with an embedded system, enabling users to monitor home security anytime and anywhere. With its stability, versatility, and low cost, the system has broad application potential in residential and small-to-medium-sized business environments.
Heat Shrinkable Braided Sleeving
braided heat shrinkable tube,braided heat shrink tubing,braided heat shrink sleeve,braided heat shrink,wiring loom wrap
Dongguan Zhonghe Electronics Co., Ltd. , https://www.zhonghesleeving.com