Design of mobile terminal for smart home security system based on iOS

Based on the design and development technology of the iOS platform, a smart home alarm system is implemented in a heterogeneous network to solve the security problems in smart homes. In this security system, the information collection end is composed of ZigBee wireless sensor nodes (monitoring nodes) in a self-organizing manner, which can collect real-time information in the monitoring area and transmit the alarm information to the server. The mobile client developed based on iOS technology can help users take corresponding alarm processing and operation measures.

1. Overall design

The overall design is shown in Figure 1. The alarm system mainly includes three subsystems: ZigBee data acquisition terminal, alarm management server, and iOS mobile client. The data acquisition terminal is connected to the alarm management server through the serial port, responsible for collecting monitoring information in the home environment, and taking corresponding alarm operations according to the hardware intelligent control mechanism. The iOS mobile client is responsible for pushing alarm information and controlling alarm operations, and is connected to the alarm management server through the WLAN/GPRS network. The alarm management server is responsible for forwarding and processing the alarm information sent by the information acquisition terminal, and responding to the operation information of the mobile client. The data acquisition terminal and the alarm management server are only briefly introduced. This article will introduce the development of mobile clients based on iOS in detail.

2. System Design and Implementation

1. Design and implementation of ZigBee data acquisition terminal

The data collection system uses Zig-Bee wireless nodes to collect and send out alarm information, uses the human pyroelectric infrared sensor (HC-SR501 human body sensing module) to sense human intrusion information in real time, and uses the door magnetic switch module (KTMC8) to sense the passive opening operation of doors or windows. This data collection solution takes advantage of the ZigBee ad hoc network's lack of fixed infrastructure and the characteristics of multi-source sensor information fusion, which can ensure the real-time and accuracy of home environment information perception.

2. Design and implementation of alarm management server

The alarm management server uses Tomcat 8.0 server, which is a free and open source Web application server. It occupies little system resources when running, has good scalability, and is suitable for small application servers.

3. iOS mobile client software design and implementation

The mobile client is developed based on the iOS mobile terminal, and the release of alarm information can be achieved through information carrying means such as text and images. Considering other unfavorable factors, such as unstable network speed of terminal equipment and changes in information processing load, the smart home alarm system based on the iOS platform in this paper uses text message push to release alarm information. After the terminal receives the push message, it reminds the user to take corresponding alarm actions on the terminal, such as turning on the light, taking a photo, making a phone call, etc.

(1) Development platform

iOS is a mobile operating system developed by Apple, and its main application targets are related mobile devices produced by Apple. The operating system has a simple and easy-to-use interface, powerful functions and super stability. According to the global smartphone quarterly sales report released by Kantar Worldpanel ComTech, in the second quarter of 2015, iOS devices accounted for 24.4% of the domestic mobile terminal device market, a record high, and more and more mobile users choose to use iOS devices. Compared with the Android platform, mobile terminal devices using the iOS system take view priority as the principle and use fewer frameworks, ensuring that developers use the hardware most effectively. At the same time, the iOS system has a high level of security, so the advantages of this type of device are mainly reflected in good user experience and a relatively safe use environment. The development of the iOS mobile client uses the non-open source integrated development environment Xcode6.1 provided by Apple, and the programming language is Object-C. The early debugging of the smart home alarm program is completed on the Xcode simulator, and the later testing and debugging are completed on the real machine.

(2) Software main program architecture design

First, enter the mobile terminal program, and the user needs to log in to the corresponding account. The mobile terminal receives the alarm message sent by the alarm management server in real time through WLAN/GPRS. If there is an alarm message, the user can take corresponding alarm actions according to different alarm messages. If the current alarm operation has been completed, it will enter the state of receiving push messages again. According to the above method, the program is executed cyclically. Figure 2 shows the flow chart of the main program of the software.

(3) Main interface design

As shown in Figure 3, the main interface of the mobile terminal application includes monitoring area, scenario settings, monitoring details and other four functional modules.

1. Monitoring area: delete or add monitoring of a specified room;

2. Scenario settings: Set different monitoring conditions for different monitoring areas, including three monitoring status settings: leaving home, returning home, and resting. In addition, users can also add other customized alarm operations;

3. Monitoring details: Display the monitoring area in the form of pictures, and users can take manual alarm actions based on this monitoring picture;

4. Others: Provides relevant information about the mobile app, such as user login, about the software, version update, etc.

(4) Alarm message push design

The mobile client uses the iOS message push mechanism to push alarm messages. The message push mechanism is completed between the application APP, the APP server (YourServer) and the APNS (Apple Push Notification Service) server. The message push process is shown in Figure 4, and the push process function is described as follows:

1. The application (APP) registers the message push service with the Apple Push Notification Service (APNS server) through the iOS system and applies for a Device Token (device identifier);

2. The APNS server sends the DeviceToken to the APP;

3. APP sends DeviceToken to YourServer (APP server);

4. The APP server sends a push message to the APNS server;

5. The APNS server sends the push message to the APP. The mobile alarm message push prompt interface is shown in Figure 5.

(5) User alarm operation design

The user alarm operation interface is shown in Figure 6. When the mobile device receives the push message sent by the APNS server, the user takes relevant alarm operations in time according to the push message, such as clicking the "light" button to realize the switch control function of the lights in the monitored area. Click the "photo" button to realize the function of taking photos and recording the monitored area. Click the "alarm phone" button to realize the dial alarm function. The above operations are all implemented on the iOS mobile client. The user operates the mobile terminal, and the alarm management server forwards the relevant operation information to the data collection terminal. Finally, the data collection terminal implements the corresponding operation to achieve the purpose of smart home security in the home environment .

3. System Analysis and Testing

Software testing is an important part of program development and also the key to ensure the normal operation of the application. The program developed in this paper was tested on two platforms, Xcode Simulator and iOS real device, including delay test and iOS device compatibility test.

The delay test includes the delay of intrusion alarm message push and security operation delay. Here, the delay includes the sum of hardware delay and software delay. From the test statistics, it can be seen that different delays have met the system requirements. The delay test results are shown in Figure 7. The compatibility test of iOS equipment includes the compatibility of the alarm system software with the current domestic mainstream iPhone models. After testing, the mobile client is compatible with the current mainstream iPhone models. The iOS device compatibility test results are shown in Table 1. After continuous testing and improvement, the delay and device compatibility of the smart home alarm system have met the design requirements.

Conclusion

The personnel intrusion alarm system based on the iOS platform designed in this paper focuses on the needs of smart home security and can be applied to a variety of different scenarios, such as homes, warehouses, small supermarkets, individual stores, etc. Combined with the wireless networking advantages of ZigBee nodes, flexible network deployment in different monitoring areas is achieved. Developed for iOS mobile clients, users with iOS devices can use the system, which will increase the target users of smart home security systems. Therefore, the design of this system is well adapted to the needs of smart home security systems and the development direction of the smart home industry. Future work will further optimize the performance of iOS mobile terminals based on the characteristics of ZigBee wireless networks, add more monitoring measures, and help users get a more perfect user experience.