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Mobile Information Systems
Volume 2018, Article ID 4237346, 9 pages
Research Article

Perception-Based Tactile Soft Keyboard for the Touchscreen of Tablets

Department of Information and Telecommunication Engineering, Incheon National University, Incheon, Republic of Korea

Correspondence should be addressed to Kwangtaek Kim;

Received 11 July 2017; Revised 2 January 2018; Accepted 9 January 2018; Published 13 February 2018

Academic Editor: Maristella Matera

Copyright © 2018 Kwangtaek Kim. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.


Most mobile devices equipped with touchscreens provide on-screen soft keyboard as an input method. However, many users are experiencing discomfort due to lack of physical feedback that causes slow typing speed and error-prone typing, as compared to the physical keyboard. To solve the problem, a platform-independent haptic soft keyboard suitable for tablet-sized touchscreens was proposed and developed. The platform-independent haptic soft keyboard was verified on both Android and Windows. In addition, a psychophysical experiment has been conducted to find an optimal strength of key click feedback on touchscreens, and the perception result was applied for making uniform tactile forces on touchscreens. The developed haptic soft keyboard can be easily integrated with existing tablets by putting the least amount of effort. The evaluation results confirm platform independency, fast tactile key click feedback, and uniform tactile force distribution on touchscreen with using only two piezoelectric actuators. The proposed system was developed on a commercial tablet (Mu Pad) that has dual platforms (Android and Windows).