A Usability Evaluation of a Laser Projection Virtual Keyboard

Abstract

This study compared typing performance using a laser projection virtual keyboard (VKB), and an electromechanical folding keyboard (FKB). Twenty undergraduate students (10 male, 10 female) participated as subjects in the study. Typing performance was measured for twelve 7.5-minute typing trials for each of the two keyboards. The results showed that typing was significantly slower with the VKB: by the twelfth typing trial the text entry performance with the VKB was 17.3 wpm compared to 40.4 wpm for the FKB, and the typing error rate was 8.6% for the VKB compared to 5.3% for the FKB. Text entry performance was 57.1% slower with the VKB than the FKB, but it was comparable to the speeds reported for other handheld device text entry methods (Multitap, T9, and handwriting recognition). A learning curve model showed that theoretically the typing speed for the VKB could reach 20 wpm after 20 hours of training.

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