Head-worn vibrotactile cueing interface for aquatic environments : design and field validation

Hribernik, Matevž (author), Tomažič, Sašo (author), Kos, Andrej (author)

Aquatic environments impose strong constraints on conventional feedback channels and challenge the deployment of wearable human–machine interfaces. This paper presents the design, characterization, and field validation of a head-worn vibrotactile interface intended for symbolic cue delivery during swimming. The proposed platform consists of a waterproof wearable node, six individually controlled actuators, a custom driver, and a host-side control application that uses a lightweight protocol and autonomous execution to tolerate intermittent wireless connectivity after submersion. Actuator operation was characterized under deployment conditions. Symbolic cues were encoded using spatial and sequential activation patterns and validated in a field protocol with 51 competitive swimmers. To enable practical scoring without additional underwater motion instrumentation, each cue was mapped to an externally observable response. After familiarization with a six-symbol cue–response vocabulary, participants produced the predefined observable responses with 96.96% overall task-level accuracy, with 99.35% in the initial out-of-water trial and 94.55% in the subsequent in-water trial following symbol familiarizing and training. Because trial order was fixed, the between-trial difference cannot be attributed exclusively to the aquatic medium. Symbol-level analysis showed that front-actuator and crawl cues were the most robust. Secondary user evaluation results indicated that the prototype was understandable and tolerable during short sessions. These results support the feasibility of trained symbolic vibrotactile cue delivery for a compact six-cue vocabulary in one head-mounted configuration in aquatic environments and provide an engineering foundation for future closed-loop aquatic feedback systems.

• Language: English
• Keywords: aquatic environments, Internet of Things (IoT), embedded systems, haptic user interfaces, human–machine systems, vibrotactile actuators, vibrotactile cueing, wearable devices, swimming
• Work type: Article
• Typology: 1.01 - Original Scientific Article
• Organization: FE - Faculty of Electrical Engineering; NTF - Faculty of Natural Sciences and Engineering
• Publication status: Published
• Publication version: Version of Record
• Year: 2026
• Number of pages: 19 str.
• Numbering: Vol. 16, issue 17, art. 8569
• PID: 20.500.12556/RUL-188609
• UDC: 004.5:681.5:797.2
• ISSN on article: 2076-3417
• DOI: 10.3390/app16178569
• COBISS.SI-ID: 292371715
• Publication date in RUL: 24.09.2026

Record is a part of a journal

• Title: Applied sciences
• Shortened title: Appl. sci.
• Publisher: MDPI
• ISSN: 2076-3417
• COBISS.SI-ID: 522979353

Licences

• License: CC BY 4.0, Creative Commons Attribution 4.0 International
• Link: http://creativecommons.org/licenses/by/4.0/
• Description: This is the standard Creative Commons license that gives others maximum freedom to do what they want with the work as long as they credit the author.

Secondary language

• Language: Slovenian
• Keywords: vodna okolja, internet stvari (IoT), vgrajeni sistemi, haptični uporabniški vmesniki, sistemi človek–stroj, vibrotaktilni aktuatorji, vibrotaktilno posredovanje signalov, nosljive naprave, plavanje

Projects

• Funder: ARIS - Slovenian Research and Innovation Agency
• Project number: P2-0246
• Name: ICT4QoL - Informacijsko komunikacijske tehnologije za kakovostno življenje