Tapulator: A Non-Visual Calculator using Natural Prefix-Free Codes

摘要

A new non-visual method of numeric entry into a smartphone is designed, implemented, and tested. Users tap the smartphone screen with one to three fingers or swipe the screen in order to enter numbers. No buttons are used-only simple, easy-to-remember gestures. A preliminary evaluation with sighted users compares the method to a standard accessible numeric keyboard with a VoiceOver-like screen reader interface for non-visual entry. We found that users entered numbers faster and with higher accuracy with our number entry method than with a VoiceOver-like interface, showing there is potential for use among blind people as well. The Tapulator, a complete calculator based on this non-visual numeric entry that uses simple gestures for arithmetic operations and other calculator actions is described.