The use of mobile bar code scanners is expanding to markets beyond popular manufacturing uses, such as healthcare, environmental testing and professional services. The successful interaction of users with mobile bar code scanners is of great importance from a business and technology perspective as well as from the user standpoint. Interaction problems associated with these devices may cause errors in data collection and affect job performance due to frustration, resulting in a potential impact on internal costs. The primary objective of this research was to develop design guidelines for the reengineering of keyboard designs for mobile bar code scanners. A secondary objective was to determine the effectiveness of current bar code scanner designs and how they can be related to other mobile technologies to develop a link across research areas. To accomplish these objectives, three different mobile bar code scanner keyboard designs were investigated: multiple-alphabetical, single-alphabetical and single split-Qwerty. A total of 42 subjects (18 females and 24 males) were recruited to participate in the experiment that was conducted to validate the research hypotheses. Time and accuracy data were recorded during the experiment and workload/subjective questionnaires were given to each participant following interaction with the different mobile bar code scanners. The following conclusions were reached based on the experimental results and are considered the major contributions of this research. First, an alphabetically laid out keyboard with multiple keys results in more time to find a character, a higher percentage of time spent typing incorrect lines, and a higher error rate than an alphabetically laid out keyboard with single keys. Perceived workload was also higher for a keyboard with multiple keys versus one with single keys. Second, no significant differences were found in the time to find a character, the percentage of time spent typing incorrect lines, and the error rate between keyboards with single keys, whether they are laid out alphabetically or in a split-Qwerty design. Finally, training a user on how to use a specific mobile bar code scanner keyboard layout often results in higher character rates, less time spent typing incorrect lines, and a lower error rate. / Graduation date: 2006

This research study examined the design of a virtual keyboard that can be used for text entry with a rotary controller, particularly when users may differ in age and experience with a particular system. I specifically examined the shape and letter arrangement on the virtual keyboard to help determine the best features to use in a design. Two keyboard shapes, an Oval and a Plus, were selected to represent different aspects of the shape. Two keyboard arrangements, Alphabetic and a Standard QWERTY-based ordering, were selected to represent a well-known and less familiar arrangement. In the experiment, older and younger adults entered words over two consecutive days. Most of the time, they used either the Oval or the Plus, but they also used the alternate shape at specific points during their practice session to allow assessment of their ability to transfer what they had learned. At the end of the second day, they also used a variation of the practiced arrangement to examine how well they had learned the letter arrangement. Text entry performance on both shapes improved as a function of practice, demonstrating that participants could learn even unfamiliar devices and virtual keyboards to complete a word entry task. No overall shape effects were found for any level of performance, but shape did affect how participants learned and performed the word entry task. In particular, unique visual features on a shape may facilitate memorization of letter/visual cue mappings. These shape features are particularly important for older adults, as younger adults seem to develop a mental model that helps them memorize letter locations on either shape. With practice, older adults could achieve optimal performance levels with an Alphabetic keyboard on the Plus shape that has the more visually unique corners. In general, alphabetic ordering is best not only because it helped visual search, but also because it facilitated better movement planning. Overall, designers should consider creating unique visual features on a virtual keyboard that will blend with the compatibility and allowed movements for the selected device to create an effective virtual keyboard.