Arto Hippula

Methods for Presenting Braille Characters on a Mobile Device with a Touchscreen and Tactile Feedback

Three novel interaction methods were designed for reading six-dot Braille characters from the touchscreen of a mobile device. A prototype device with a piezoelectric actuator embedded under the touchscreen was used to create tactile feedback. The three interaction methods, scan, sweep, and rhythm, enabled users to read Braille characters one at a time either by exploring the characters dot by dot or by sensing a rhythmic pattern presented on the screen. The methods were tested with five blind Braille readers as a proof of concept. The results of the first experiment showed that all three methods can be used to convey information as the participants could accurately (91-97 percent) recognize individual characters. In the second experiment the presentation rate of the most efficient and preferred method, the rhythm, was varied. A mean recognition accuracy of 70 percent was found when the speed of presenting a single character was nearly doubled from the first experiment. The results showed that temporal tactile feedback and Braille coding can be used to transmit single-character information while further studies are still needed to evaluate the presentation of serial information, i.e., multiple Braille characters.

Experiences on haptic interfaces for visually impaired young children

Visually impaired children do not have equal opportunities to learn and play compared to sighted children. Computers have a great potential to correct this problem. In this paper we present a series of studies where multimodal applications were designed for a group of eleven visually impaired children aged from 3.5 to 7.5 years. We also present our testing procedure specially adapted for visually impaired young children. During the two-year project it became clear that with careful designing of the tasks and proper use of haptic and auditory features usable computing environments can be created for visually impaired children.

Testing usability of multimodal applications with visually impaired children

Testing multimodal applications with visually impaired children requires specific testing methods and procedures. In this article, we used a SensAble Phantom device to produce haptic feedback together with stereo sound and visual feedback. We also experimented with low-cost haptic devices, such as force-feedback game controllers and tactile-feedback devices. Here we discuss how to conduct usability testing for multimodal applications with visually impaired children