I. Project Overview
By the beginning of the 21st century, RFID has ushered in a new era of development, and its value in the civilian field has begun to receive widespread attention from all over the world. RFID (Radio Frequency Identification), that is, radio frequency identification. RFID radio frequency identification is a non-contact automatic identification technology. It automatically recognizes target objects and acquires relevant data through radio frequency signals. The identification work can work in various harsh environments without manual intervention. RFID technology can recognize high-speed moving objects and recognize multiple targets at the same time, and the operation is quick and convenient.
1.2 Project Background / Motivation
Mobile phones have become an indispensable part of people's lives. As a result, cases of mobile phone theft in life often occur. Especially the precious mobile phone is the target of the thief. The theft of a mobile phone brings not only the payment of money, but also the loss of important information in the mobile phone. The burglar of the mobile phone slowly enters people's field of vision. RFID technology can achieve the function of mobile phone anti-theft.
Second, the demand analysis
2.1 Functional requirements
This design mobile phone anti-theft completes the following tasks:
First: timely anti-theft
Second: mobile phone stolen pursuit
Third: prevent mobile phone legacy
Figure 1 System Architecture
2.2 Performance requirements
When the thief is connected to an abnormal situation and touches the mobile phone, it is enough to inform the owner at the first time.
Determine the phone is stolen, provide information, and quickly locate the target phone
The phone leaves a certain range, reminding the owner that the phone may be dropped
Provide a useful information interface
Third, the program design
3.1 System function realization principle
Under normal circumstances. There is an RFID tag on the person's hand. When the legal right touches the phone, the phone can be used normally. When an abnormal situation such as a thief is accessed, when the mobile phone is touched, the ambient temperature of the mobile phone changes accordingly. The device on the mobile phone opponent is compared with the line information. When the confirmation of the abnormality is determined to be a risk of being stolen, the user is reminded to issue a prompt and an alarm.
Second: mobile phone stolen pursuit
When the mobile phone is accidentally stolen away from the household owner, the handheld device responds to the user by exceeding the set range. When the user determines that the mobile phone is stolen, it enters the RFID distance ranging mode. The mobile phone owner can find it according to the distance between the mobile phone and the user. This allows for a quick positioning of the phone and the ability to retrieve the phone in the first place. When the direction of the owner and the direction of the mobile phone are opposite, the display distance can be expanded. When the direction of the owner and the mobile phone are the same, the distance can be displayed, which can guide the owner's search.
Third: However, setting the distance between man and machine, this can give reminders to the owner of the mobile phone when it is left behind, effectively preventing the owner from leaving the mobile phone. Let the phone get the best protection.
3.2 Hardware platform selection and resource configuration
The evaluation kit based on the AVR32 AT32UC3A microcontroller controller and the development system EVK1100 are selected.
AVR32 AT32UC3A has a single-cycle RISC command system to meet the needs of high-speed communication and data processing.
It has read and write and address latch enable control pins for easy expansion and use of external interfaces and external storage space for easy connection to communication units.
3.3 system software architecture
1. The modularity of each module is modular;
2. The main program determines whether the mobile phone has an abnormal state;
3. Abnormal state processing;
4. Setting of safety distance;
5. Collection of temperature;
6. Setting of human-computer interaction interface;
7. Consolidation of security.
3.4 System Software Process
Program flow chart
3.4 System Expected Results
The wireless RF transceiver and ranging module uses Nanotron's NanoPAN module. The module uses wideband linear frequency modulation spread spectrum (CSS) technology and is adopted by the IEEE 802.15.4a standard. The transceiver is a 2.4 GHz ISM band wireless device that provides flexible data rates from 31 25 Kb/s to 2 Mb/s with high point-to-point ranging accuracy and reliable data with excellent transmission range. Communication. By using a MAC controller, the requirements for microprocessors and software can be reduced, and the design of high-level systems can be easily accomplished. This module is one of the important core parts. The focus of theft. Finally, the device has a high level of anti-theft.
Design work adds a simple interpersonal interface.