BackgroundAs part of my work as a Research Assistant in Penn State's Center for Human-Computer Interaction on a project called Third Eye, I assist in studying emerging assistive technologies for the visually impaired. We are especially interested in remote sighted assistance, a technology through which people with visual impairments can share the video feed from their phone camera with a remote sighted assistant. The remote sighted assistant generally provides verbal or text-based feedback to the user based on what they can see from the video to help users complete various tasks, like grocery shop or navigate. Because the pace of speech is limited, we sought to add a new sensory channel into the interaction and send users directional information through vibrations, or haptic feedback, (model at right).
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Design Goals
To add haptic feedback into this assistive interaction, we needed to design a hardware component to facilitate delivery of vibrations from the assistant to the visually impaired user. We considered vibrating components on a glove or vest for the user, but these concepts were determined by visually impaired testers to be too imposing and inconvenient. We then pivoted and began developing a wristband with vibration motors on it. I led the conceptual design while other team members constructed the prototype. Based on our previous interactions with people with visual impairments, our goals were to make the wristband compact and comfortable and to ensure that vibrations convey directional cues in four directions clearly and distinctly.
Design ProcessIn accordance with the above design goals, my conceptual design included a flexible fabric wristband with vibration motors on the top, bottom, left side, and right side. Through a Bluetooth connection in the circuit, remote assistants can send a vibration to any of the four motors based on which direction they would like to signal to the user. The first prototype produced (at left) included a small breadboard in place of a much smaller PCB.
I assisted in designing and conducting an experimental study in which people with visual impairments tested the prototype in a dinner table scenario (at left). Participants used a smartphone camera to transmit live video to a sighted assistant in a separate room. The assistants gave users verbal and haptic information to help them navigate their hands around the dinner table to reach items of interest without knocking anything over. After testing the prototype, participants gave us feedback on the prototype.
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OutcomeUsing the results from the study, I worked with electrical engineering students to iterate on the prototype. They created a more compact electrical circuit, and I revised the wristband design to make it more comfortable and make the vibration location less ambiguous. The vibration motors in the newest prototype are more powerful and on the outside rather than the inside of the band to avoid putting uncomfortable pressure on the wrist. This design iteration addresses the concerns from users in the study and is expected to perform better with respect to user needs. Our next step will be to conduct a second round of user testing.
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© 2020 Madison Reddie