'Touching for Knowing': Design and Evaluation of Wearable and Graspable Haptic Devices for the People with Visual Impairment


Student thesis: Doctoral Thesis

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Award date26 May 2022


With the growing number of mobile and digital devices, there is a huge increase in mobile notifications pertaining to a wide range of tasks such as navigation, messages, calls, etc. Visual cues primarily dominate interactions with such devices and interfaces. However, visual interaction may not always be the most efficient or intuitive method for performing some dedicated tasks in particular environments. For instance, situational vision impairments can occur when we try to use Google Maps under bright sunlight or when looking for navigation signs on the mobile screen while driving. For the effective offloading of physical and digital information to the users, non-visual interaction methods using audio and haptic modalities are widely adopted. Moreover, such non-visual interaction methods can help people with blindness or visual impairment when visual interfaces are impractical and meaningless. When it comes to education, independent navigation, and accessing notifications, the blind and visually impaired (BVI) community faces several challenges due to the increasing amount of digital information and complex environments. In such cases, haptic interaction methods have proven to help the BVI access helpful information and notifications. With haptic interaction in focus, I present three designs of wearable/graspable devices in this thesis, such as the FingerTalkie, ThermalCane, and ThermEarhook, which can help address some of the issues faced by the BVI in the above three domains.

I start with the design and evaluation of FingerTalkie, a finger-worn haptic device that enables BVI users to obtain simultaneous audio information of a specific area of a tactile diagram with a simple and intuitive tilt-click gesture. The device helps the visually impaired students shorten the exploration of Braille legend pages in the tactile textbook and obtain the same information through audio. Based on the quantitative and qualitative experiments, the design proves to be a reliable device for visually impaired students to receive real-time audio information from a tactile diagram. However, during the experiments conducted using the finger-worn haptic device, I also observed that there could be instances where a blind user needs to pay better attention to the audio cues from the surrounding environment. One such scenario would be when a BVI person is performing outdoor navigation. In such instances, the user is likely to benefit from some level of increased haptic feedback instead of audio-based feedback so that their attention can be maximized.

The BVI people already use vibro-haptic-based electronic canes for outdoor mobility and obstacle detection. However, they do not provide any navigational instructions to the users. Relying on audio-based navigational instructions can be a threat to users when they need to listen to the ambient sounds. Therefore, I designed ThermalCane, an electronic grip for the white cane that provides multi-point thermal feedback to convey turn-by-turn navigation instructions to the BVI user on the go. From the real-world walking experiments with the VI users, the thermal haptic feedback proved to be a helpful modality for conveying information to blind users where audio and vibration haptics tend to work less effectively. The above experiment further paved the way to investigate thermal haptics with an ear-worn form factor for the BVI.

Finally, I present the design of the ThermEarhook, a wearable earhook with embedded Peltier modules, to understand the feasibility of delivering notifications from electronic devices using thermal haptic feedback. Initial tests were conducted to understand the thermal sensitivity(hot and cold) and threshold on the back of the ear. Further, single-point and multi-point combinations of thermal patterns were tested to obtain the optimal combinations that were used for notifications or other instructional feedback for the BVI users.

Other than auditory interfaces, assistive technologies based on haptics have always been important for the BVI in the fields of accessing print information, mobility and navigation, and accessing smart notifications. Through this thesis, I present the designs and evaluation of a finger-worn device, FingerTalkie to increase the efficiency of tactile graphics literacy, ThermalCane for independent outdoor navigation, and ThermEarhook for easy access of mobile notifications by leveraging the wearable/graspable form factor and combining it with various active and passive haptic input methods. With the ever-increasing amount of complex visual information around us, haptics remains essential for the BVI to explore and understand the physical environment, which can help them in their day-to-day lives.

    Research areas

  • Haptics, Blind, Visually Impaired, Accessibility, Wearable device, Touch