Vibrotactile Feedback for Application on Mobile Touch Screen Devices: Effects with Age

This thesis has investigated vibrotactile interactions for touch screen devices related to age, the study developed distinguishable vibrotactile patterns for evaluation by younger and older people, in order to inform the design process for the development of a haptic language.
The study of haptic perception validated that the optimal sensation to vibration for both age groups is in the range of 100-300 Hz, which guides the design of the future vibrotactile patterns development.
As part of the human perception study carried out, it was found that two of the seven semantic differential pairs tested, ‘slow-fast’ and ‘light-heavy’, are suitable to describe the feelings of haptic feedback for younger people however there was no clear agreement for older people. It is recommended that the magnitude estimation techniques can be used for the future experimental design.
Finally, this study shows that haptic language could be developed using vibration with the respect to the parameters of amplitude, frequency, and frequency ramping. The amplitude of vibration plays a key role in determining whether people can adequately sense the message, whereas the frequency can be used to imply meaning.
The study found that a signal at 200 Hz could be understood to have a positive meaning for the vibrotactile interaction. Frequency ramping could be an essential parameter to design a negative vibrotactile interaction, compared to amplitude ramping that has no significant influence for perception. Most people would require a certain level of training to learn a haptic language because humans have no pre- conception of vibrations other than as an alert. It is suggested that a scenario should be provided to the subjects for the valuation.