| Infrared handle feedback system is an important component of"Information based teaching tools and the application of basic platform".It can achieve the interaction and feedback between teachers and students in the classroom by using Irda,Wireless and so on short-range wireless communication technology..the paper compared advantages and disadvantages of each short-range technology .At last,our group decided to adopt the Irda technology for whose wide application confine,strong anti-jamming ability and lower price.The Infrared handle feedback system based on Irda can achieve kinds of functions that included testing in classroom,choosing game , voting by hand up and so on;The way that make the function-strong Infrared handle feedback system and rich and colorful teaching soft work together can encourage the students more active;Besides that,it can achieve the functions of calling the roll,answer stat and teachers test;make the teaching mode based on students to be true.The main tasks and contrubutions of this paper are as below:(1) Access to project information on the development of related products at interior and abroad to conduct a detailed summary, and its technical indicators, functional types were compared, the design for the project the direction and laid the foundation for goal.(2) This paper has fully researched the short-range wireless communication technology and bring forward the solution scheme that based on Irda communication technology for the Infrared handle feedback system.(3) This paper has completed the hardware of the Infrared handle feedback system in which it included the design of one teacher control device,students handle devices,Infrared receiving device and numbers transfers device.The detail work contained the choice of the coding and decode chip, improving of the keyboard and the filter dispose for the power.(4) Tihis paper has completed the kernel content of communications agreement where it included codeing program that well solve the question of Infrared signal mixed.Besides that,it designed the program of the teacher control device students handle devices,decode of receive device and numbers transfer decive and make their functions to be true.(5) This paper completed the designing of the PCB layout and the test of the performance for the Infrared handle feedback system.At the end,in which it gave the performance parameter and creative points which establish the base for achieving the application in classroom earlier.The paper is divided into six chapters,the detail agreement as following:Chapter one summarizes the background,sifnificance,compositions functions roles of the Infrared handle feedback system,development situation of native and overseas and introduces the research contents of this paper.Chapter two introduced several usual short-distance wireless communications technology and put forward the solution sheme based on Irda communications technology by comparing their characters of each other.Chapter three fully states how to design the hardware of the Infrared handle feedback system.in which it include one teacher control device,students handle devices,Irda receiving device and numbers transfer device.Besides that,it achieve the design of low power circuit by testing for many times.Chapter four fully introduced the kernel content of the communications agreement,by which it well solve the question of Irda signals mixed .what's more,in which it design the program of the teacher control divice, the students handle devices,receiving decode and numbers transfer.after that it achieve the matched functions.Chapter five designed the layout PCB of the system and tested the hardware and software of the system.In which it gave the performance parameter and the creative points of the Infrared handle feedback system.Chapter six is the summarization and expectation of this paper.The research significance of the Infrared handle feedback system lies in:the system creates a new concept of interactive teaching.It is the breakthroughs of education and technological.With the technological innovation,education has advanced at the same time.Its application has changed the one-way instilling teaching mode of tradional classroom teaching,fully embodied the students as the main mode of instruction,deepened educational technology products in the teaching of applications and made the classroom equipment,such as computers,products in the teaching of applications andmade the classroom equipment,such as computers,projectors,with the help of the multi-media teaching resources as well as the Infrared handle feedback system,play anew effectiveness and create more teaching mode applications.Infrared handle feedback system,by working together with Interactive Electronic Whiteboard,Subminiature Electronic Whiteboard and Wireless Discussion Board System and so on,can implement"Information based teaching tools and the application of basic platform",which has pioneered the high integrity of the information and interactive teaching environment,promoted the classroom teaching information.At the sametime,it conforms to"11th Five-Year"plan for accelerating education information pace and has great realistic and long-tern significance.The important points of this paper are as follows:(1) Infrared handheld hardware driver feedback circuit is designed to be a major important point in this article point, the driver circuit and a common infrared remote control driver circuit is different from ordinary infrared remote control drive circuit is based on fixed models of infrared encoder chip external transistor to enhance infrared transmission power in order to drive the launch tube, the distance to reach the launch, although the coding of such a fixed model easy chip driver circuit, but its not in the program, which can not meet the system requirements. In this paper, the infrared encoder chip AT89S51 While easy to program, but the drivers do not have a fixed capacity and chip-driven models of coding ability, so the external circuit to drive the transistor alone are not ideal to send from and to this end at Chapter III of the impact of our combined distance infrared communications relevant factors, to its external drive circuit has been designed to be able to in the application code AT89S51 microcontroller chip drive capability when the same degree of ideal, so that hand-held infrared communication feedback system to achieve the desired target distance.(2) Another major important ponit of this article is that the design of system communication protocol, the communication protocol design, including model of communication protocol, infrared hand-held device codec design. Communication model in the set up process of our people shall not be taken into account the reaction time and calculated the reaction time of two people when the model structure, in theory, more than at the same time resolved infrared communication signals superimposed the problem. In addition, the infrared signals are original codec design, and in the design of our code using the signal "1" and signal "0" pulse of the low-level coding for the 3:1, the same time, we greatly reduced the width of the unit. Decoding at the design of the filtering process we add. This codec is designed to inherit the infrared remote control law codec, and the advantages of anti-interference ability and its wave length to make up for too many road communication at the time of the lack of easy to have a superposition, at the same time also for the increase in decoding the last line of "barrier" filter software. Solve the multi-channel infrared signal is sent at the same time prone to severe difficulties in the stack, the system test phase at a lower bit error rate greater reliability.The innovatives of this paper are as follows:(1) In this paper, a programmable peripheral chip encoding circuit design-driven, so that the distance between the systems of communication to achieve the desired result, the receiving device increases the coverage area of the classroom, saving the expansion of the number of the receiving device, so that resources in the process of teaching can be fully utilized.(2) In this paper, the communication protocol design, in theory, to solve the multi-way infrared communication signal superimposed this issue easily, so that the handheld infrared feedback system used in many cases more reliable and safe. At the same time if the need to increase the number of users, by improving the communication protocol can meet the requirements.There are still some problems concerning the manufacture of Infrared handle feedback system remaning to be solved:(1) The performance of the number transfer device is not stability,the situation of decode and dead usually appeared,to hope improving tthis situation and make the system work more stably.(2) The teaching soft need to be improved and make stronger so that make the funcitions of Infrared handle feedback system more important and make it more practical..(3) Optimization of communication protocols is an important and hard task, to explore a more rational and more efficient communications protocol will make the Infrared handle feedback system more credible. |
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