Design Of Ultrasonic And Infrared Electronic Whiteboard System Based On TOA Wireless Location Algorithm

Science and technology innovation has driven development of multimedia education, interactive electronic whiteboard's emergence promote educational patterns of development by leaps and bounds. It's a Interactive platform of information with a variety of means of information technology, integrates information technology and all Subject curriculums,it's the best performance of complementary advantages between traditional education and modern education, has made the reform of educational information. Has give rise to a great deal of convenience because of its health and environmental protection,human-computer interaction and remote network, will play a big role in educational information.This paper explains the function of kinds of electronic whiteboards, compares a wide range of electronic whiteboard technological advantages and disadvantages. This paper integrates with the latest research achievements at home and abroad, It proposes to adopt planar positioning method combing Ultrasonic and infrared, the function of electronic whiteboard based on Ultrasonic and infrared has been described. Based on kinds of estimation location algorithm,this paper analysis TOA estimation location algorithm that we take in depth and detailed.At the same time, noise sources in the electronic circuit and a variety of anti-interference technology have been explained.In this paper, this system's signal transmitting circuit,receiving circuit,temperature compensation circuit and serial communication have been described. In order to make the system receiver sensors can effectively detect the signals from the signal pen, Ultrasonic sensors and infrared sensors whin signal pen need to emit horizontal 360-degree omni-directional signal, it has chosen PVDF Ultrasonic sensor which affords honrizontal 360-degree omni-directional emission,and it has applied four pieces of Gallium arsenide infrared emission diodes which afford 120-degree emitting angle integrated 360-degree omni-directional emission.To reduce the volume of the signal pen, it has used the smallest eight pins single chip PIC12C508A as the transmitting terminal microprocessor.In the receiving circuit, Impedance matching circuit,low-noise bias circuit and mu-circuit have been decribed in depth and detailed. It has also compiled the software program of system emission signal,the software program of receiving and extracting time signal and the temperature sensor's temperature measurement,and the serial communication has also been set up.In the receiver of electronic whiteboard,Ultrasonic signals at all levels of output waveform has been tested,and the ideal waveforms have been obtained. Through measuring the fix point of Electronic white board, and extracting time-delayed signal and calculating the error value caused by the actual measurement, it proves that Electronic whiteboard on Ultrasonic and Infrared in this paper can satisfy enough with the needs of human eyes to observe.