The Design Of Electronic Pen System Base On Acceleration Sensor

To be a new human-Computer Interaction tools, electronic pen have an extensive application space. With MEMS technology matures and three-axis acceleration sensor of single-chip appears on the market, electronic pen of acceleration type must bring more innovation with its low price and more user-friendly design.This paper focuses on these questions, it analyses and researches the electronic pen of acceleration type. Electronic pen of acceleration type obtain the trajectories of the nib through the mathematical of acceleration based on kinematics algorithm. Combination of handwriting analysis algorithm can be shown to complex, it has simple structures and easy to be implement.MMA7260QT is a low gravity of the three axial accelerometer based on micro-electro-mechanical systems (MEMS) of Freescale, it specifically for portable consumer electronic products. It can reading XYZ three axis in the fall of low-gravity level, tilt, move, place, vibration and swing on the very high sensitivity. It is a three-axis acceleration sensor of the first single-chip in the similar product. This paper designs the major modules for electronic pen in the hardware and software based on MMA7260. Which power supply module used USB bus-powered, USB bus-power provided to the equipment by the largest 5V/500mA, it can supply the needs of system in the normal working.USB data acquisition is to upload data through the USB bus. USB communication uses USB interface chip of philips. The chip used in microcontroller-based systems and high-speed general-purpose microcontroller parallel interface to communicate, it also supports local DMA. The data acquisition application system of electronic pen based on acceleration sensor with LabVIEW, the data acquisition systems integrated the advantages of both LabVIEW language and to closely combine the USB bus. USB bus can be achieved external data collection in real time on high-speed, USB can send the collected data to the host then save the data with the functional modules of LabVIEW.In the theory, acceleration to displacement have two points, points can be achieved in the time-domain, using the numerical integration method of trapezoidal for points and other direct integration method. This article uses the points in frequency-domain through MATLAB, the basic principles of the signal points will be required for Fourier transform, and then the results of transform will be carried out in the frequency-domain, finally, we can get the integral of the time-domain signal by the Inverse Fourier Transform.The article analysis on the three-dimensional projection in the last, if you want to display the three-dimensional images in two-dimensional, it is necessary to reduce the dimension.