Abstract

Few industries have changed so much in such a short time as the computer industry, and the pace of change shows no sign of slowing. The computer now has a role in almost every aspect of modern life, and it has radically affected the way people organize their lives. Desktop users have to push a mouse around their desktop while laptop users can just point a finger on touchpad. Touchpad is a type of computer input device which uses a touch sensitive surface to allow users to control the movement of a cursor, thus replacing a mouse, pointing stick or trackball. Instead of requiring a user to grasp a mouse and pivot at the wrist to click and track on the desktop, touchpads require less motion and allow users to situate their hands and arms in a variety of positions which results in less stress on wrists. Another major advantage of touchpads is that they take up less space than a traditional mouse so it is ideal where space is at premium. Therefore, many users and computer makers see touchpads as a viable, long-term alternative to other pointing devices. Therefore to benefit desktop users, the low cost embedded touchpad is proposed. It uses 4 wires resistive touchscreen to sense the position of a finger. The other hardware includes touchscreen controller circuit, AT89S52 microcontroller, MCP3208 ADC and MAX232 voltage converter. The software is written in Microsoft Visual Basic to operate curser on the screen.

References

• C. Forlines, D. Wigdor, C. Shen, R. Balakrishnan, 2007. Direct-Touch vs. Mouse Input for Tabletop Displays, CHI Proceedings, pp. 647-656
• Datasheet of 4 wire analog resistive touchscreen model HT043A-NCNBD52-R http://www.hantouchusa.com/4_-_wire.htm
• S. Pietri, A. Olmos, M. Berens, A. V. Boas, M. Goes, 2009. A fully integrated touch screen controller based on 12b 825kS/s SAR ADC, Micro-Nano electronics Technology and Applications, pp. 66 – 70
• T. Hoye, J. Kozak, 2010. Touch screens: a pressing technology, Tenth annual freshman conference, pp. 1-6
• R. N. Aguilar, G. C. M. Meijer, 2002. Fast interface electronics for a resistive touch-screen. Sensors, Proceedings of IEEE, Volume 2, pp. 1360 – 1363
• Datasheet of AT89S52 http://www.atmel.com/Images/doc1919.pdf
• Datasheet of MCP3208 http://www.microchip.com/downloads/en/devicedoc/21298c.pdf
• M. A. Mazidi, J. G. Mazidi and R. McKinlay, 2007. The 8051 Microcontroller and Embedded Systems Using Assembly and C, 2 edition, Pearson Education
• Datasheet of MAX232 http://www.maximintegrated.com/datasheet/index.mvp/id/1798?ver=C&utm_expid=50713806-2&utm_referrer=http%3A%2F%2Fwww.maximintegrated.com%2Fdatasheet%2Findex.mvp%2Fid%2F1798%3Fver%3DC
• E. Petroutsos, 2010. Mastering Microsoft Visual Basic 2010, Wiley India