Use and Research Issues of a New Computer Keyboard

Abstract

For use with computers, the traditional QWERTY keyboard has been enlarged to more than 100 keys. This has generated postural and motoric challenges for the user, including cumulative trauma disorders. Among the proposed ergonomic solutions is the Ternary Chord Keyboard (TCK) which has only eight keys. Its evaluation posed use and research issues. TCK operation requires fast and finely controlled force and displacement by the fingertips in a horizontal plane, i.e., “rocking” of keys instead of their familiar “tapping”. Associated mental tasks include memorization of the chords for each character. Experiments were performed (a) on TCK prototypes to measure the time needed to memorize and learn its operation, and to assess keying performance; and (b) on specially designed experimental apparatus to measure finger mobility, strength, and speed. The results indicate that finger mobility, strength and tapping performance were not well correlated with keying performance. All subjects were able to learn to operate the TCK, requiring memorization of 58 chords, within two to ten hours. After additional about 10 hours of use, they were inputting averages of 70 characters per minute, or more, with an accuracy of better than 97 percent. These results indicate that key operation such as with the TCK, which is rather different from the traditional QWERTY keyboard use, is feasible.