陕西理工学院毕业论文
附录A 外文翻译原文
AN ELECTRONIC DIGITAL COMBINATION LOCK
[Abstract] At present, key-pad electronic lock with alarming funtion is to gradually replace the traditional
mechanical locks,overcoming the shortcomings of the traditional mechanical locks which contain few password and lack of reliabiIty, but keypad electronic lock makes a great progress in terms of technology and performance.This paper represents a type of remote-controlled electronic lock developed with the chip of AT89S51. This type of lock have two input devices,one of them is a 4*3 matrix keyboard mounted on the lock,the other one is a remote controller which also have 4*3 matix keyboard.we can use either of them to open the lock or change the password we have set. In the design,we adopt the infrared ray as the medium,because of the strong anti-interference ability, reliable transmission of information.
[Index Terms] MCU; Electronic locks; Infrared Remote-control; LCD1602 I. INTRODUCTION
The design is based on single chip,makes use of 4 * 3 keyboard and infrared remote controller as input,LCD1602 could display the information of the steps when you are operating.This designment could also realize modifying the password and alarming. When a requirement to reset the password,it is necessary to make sure the password is correct,otherwise it will make noise to warn you the password is wrong.In this designment,1 limit the length of the passwordat six,Just like the ATM of bank.you must enter right password if you want to get through.
II. THE FRAMEWORK OF THE DESIGNMENT
The designment consists of six modules: the main controller module, LCD1602 module, 4*3 keyboard module, infrared remote control module, the alarm module, the unlocking simulation module.
Main Controller Module: a low-power, high-performance CMOS 8-bit single chip, the device used ATMEL's highdensity, non-volatile memory technology, compatible with standard command system of MCS-51.An 8-bit common central processing unit and ISP Flash memory cell are integrated in this chip.
LCD modules: LCD1602 is a character liquid crystal display modules, is a type of dot-matrix LCD dedicating to display letters, numbers, symbols and so on.Considering economy and practice in this regard,adopting LCDl602 is enough to meet the requirements of character displaying on the LCD.
4*3 keyboard module: Because of I/O port of MCU is limited, according to matrix keyboard to realize circuit.In this way,we can design enough buttons on the keyboard but not take up too many ports of the MCU. Infrared remote control module: the design used a universal TV remote controller as input device,the device can provide a wide range of infrared encoding format, so we make use of the coding format of the pulse width modulation.
Alarm modules: In this design, select the buzzer to sound a warning. The single-chip through the port P3.2 outputs a square wave pulse-driven audio loudspeakers.
Unlocking instructions: In this design,1 choose to use LED lights to simulate the situation of the lock.when we enter password,LED lights will flash on behalf of the unlocking is successful.
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陕西理工学院毕业论文
Figure 1.The framework of the designment
A. The design of Matrix keyboard
Matrix keyboard working principle: vertical lines through the resistance connected +5V power.when no keys are pressed down,the vertical lines is in high level situation,otherwise ,the situation is the same with the horizontal line's which is crossed on the button.Originally ,the horizonal lines are in low-level, when we check the varying situation of the vertical Iines,that means button is pressed down,at this time we save the situation of port p2.4-p2.6,then we program to make the port p2.0-p2.3 in high level situation line by line,at the meantime checking the varying of the situation of the port p2.4-p2.6,when it changes,we save the situation of the port p2.0-p2.3.In this way,we have known which button had been press down,because we have recorded situation of the port p2.0~p2.6.Different keys have different coding format, the keyboard processing tasks are:Firstly, to determine whether or not press the button,then check which button have pressed,through the programming,get the formation of key coding.
B. The design of infrared remote – control 1) The introduction of the LC7461
At present,there are lots of chips dedicating to transmit the infrared ray, in terms of the encoding format that can be divided into two major categories: PWM and PPM. Here we have adopted a relatively easy to modulate,the PWM's, LC7461 chip. When the infrared controller'button is pressed,it will send out some signal which contains the information about the coding format.The signal has the following characteristics: the PWM pulse width last for 0.56ms, interval 0.56ms as a period of 1.12ms representing the binary \width last for 0.56ms,interval 1.68 ms as a period of 2.24ms representing the binary \\launch in order to enhance efficiency and reduce lower power consumption, andthen through the infrared diode to send out. “0”“1”
2) The infrared receivers
Infrared receiver is an integrated circuit including a set of funtions of receiving,amplification and shaping, without any external components,takes all the work compatible with TTLlevel, it is suitable for a variety of infrared remote control and infrared signal transferring.Infrared receiver transmits the demodulated signal to the single-chip AT89S51 by the way of interruption. NOTE: When there is no infrared signal,the output port is in high-level,so the signal we received is contrary to the signal sent out before. 3) The decoding of the infrared signal
When we receive a signal containing a synchronized beginning of 9ms low-level and 4.5ms high-Level,it
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陕西理工学院毕业论文
makes us prepare to decode the data.The key of decoding is how to identify \and \According to the formation of the signal we can find that the definition of \difference between them is the width of the high-level, \to compare the current level for identifying the bit,the flow chart as follows:
Figure 4. The flow chart of decoding
4) The working process of the infrared remote-conroller
IR transmit / receive control circuits are achieved by the AT89S51microcontroller with simple circuit, selectable output control method and very practical The specific work process is as follows:
Launch: First, sent back the data from the serial transmit port P3.1 to the P1.1 port for internal modem, sent out from the P1.2 port, and then fired out through the infrared emitting diodes, firing distance is about 10m. Receipt: The infrared receiver head matched with the launch is used. , sent out the data launched to the serial port 3.0, and then the system will confirm whether the send data are consistent with the receive data, yes will unlock, no will give up.
C. The design of main circuit
According to the design of the analysis, the hardware circuitry of single-chip electronic locks as shown in the Figure below. P0port connect LCDl602 8-bit data bus,at the same time, P0port is connected to the 8-bit ports of anode-sharing digital tube,the port of P0.1strobes LED. P2 port access 4 * 3 matrix keyboard circuit, while P2.5, P2.6 and P2.7 respectively connect the RS, RW, E-port of the LCD1602. Buzzer alarm prompted by the P3.2 output.
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陕西理工学院毕业论文
Figure 5. The design of main circuit
III. RESULT
Accrding to the design ,the operation is shown as the figures below: Figure 6. a unlocking interface
When we want to reset the password,firstly,the system checks out the password is correct or not,if the password is right,we could get in the next step,otherwise the system makes warning. Figure 7. Interface of checking the password Figure 8. Interface of reset password
Figure 6.7.8
IV. COCLUSION
In this paper, an infrared remote control electronic locks was designed and implemented, the main technical indicators are: the lock opening, password storage, the effective protection of user's password, auto-alarm if the wrong password, unlock the keyboard of the machine, remote unlocking and other functions. Because of infrared remote control used in this lock system, there are many advantages: Infrared launching device use infrared light-emitting diodes miniature remote control transmitter is easy and inexpensive; use digital signal coded modulation to improve anti-interferencewhen signal are transmitted, less misoperation , low power consumpti-on, including other advantages, such as fast response infrared transmission, high transmission
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陕西理工学院毕业论文
efficiency, stable and reliable operation .Based on these advantages, this lock can be widely used in civil doors and warehouse doors. In the information age,in my opinion,the design could play an important part in our daily life and will supplant the tranditon traditional mechanical lock later on.Though there is some points needed to improve, I also make further research on it to improve the funtion. ACKNOWLEDGMENT
The authors of this paper would like to thank the anonymous reviewers of this paper for their carefully reading of the manuscript as well as their many helpfully suggestions and corrections. This project is supported by the Planning
Project of the National Eleventh-Five Science and Technology (2007BAK34- B04) and the Chinese National Natural Science Fund (60704042) and the Program of 985 Innovation Engineering on Information in Xiamen University (2004-2007).
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