Ear Haptics: A Preliminary Suitability Study of a Novel Auricular Haptic Human-Machine Interface

Objective: Following both software and hardware development, this study presents the development of the EarPi system – a new haptic human-machine interface (HMI) that produces vibrotactile feedback at four ear locations of the auricle. This paper details the development of all system components and presents key findings from a preliminary semi-structured interview, providing insight into both user attitudes towards ear-based haptics and initial impressions of the experimental prototype. Method: The HMI has been designed using Fusion 360 and 3D printed using an UltiMaker Method X. This paper outlines the development from concept design and 3D modelling to manufacturing, software development, and electronic component integration. All software, hardware, and methods employed are presented to provide insight for future research and development. The study involved 26 participants answering two sets of semi-structured interview questions separated by a familiarisation task. Interview answers were synthesised and coded to find key themes. A theme was included as a significant result if the frequency among participants was at least 10%. As there were 26 participants, a frequency of 3 was selected to be counted as a key theme. Results: Familiarity with haptics, openness to the technology, perceived usefulness, and excitement for future development was high among participants. Participants were divided on the comfort level and texture of the earpiece but did not see the weight and aesthetics as a problem. Work must be done to improve the design of the earpiece clip and centre column. Various other improvements, such as adding rubber, smoothing out the surface, making the sizing adjustable and improving the way it attaches to the ear emerged as primary problem points. Conclusions: A fully functioning HMI prototype has been successfully developed following an iterative design process. Preliminary interviews show a high level of acceptance towards the use of ear-based haptic HMIs, while highlighting the importance of developing bespoke devices tailored to the specific needs and physiology of each individual. Clear design improvements emerged and will be taken forth into future design iterations.