What we study
Research
Six interconnected themes spanning vibrotactile perception, prosthetic feedback, sensory substitution, spatial audio, room acoustics, and human attention — each grounded in formal experiments and informing device design.
Vibrotactile Perception
We map the perceptual limits of touch in response to vibration. Maximum sensitivity at the wrist peaks at 200 Hz on the inner surface; individual thresholds vary enormously, requiring personalised calibration.
Presenting patterns sequentially yields 93% recognition accuracy, versus 26% with simultaneous stimulation.
Key publications
- Yeganeh et al. (2024). Sequential vs. simultaneous stimulation. Applied Sciences. doi:10.3390/app14010043
- Yeganeh et al. (2023). Frequency & location on the forearm. Actuators. doi:10.3390/act12060224
- Ævarsson et al. (2022). Vibrotactile thresholds at the wrist. ACM TAP. doi:10.1145/3529259
Prosthetic Haptic Feedback
We design forearm-based vibrotactile systems that route signals from prosthetic sensors to a wearable sleeve, restoring a proxy sense of foot position for transfemoral amputees. Sequential patterns achieve 72% recognition accuracy — nearly double the 43% with simultaneous patterns.
Developed with Össur ehf. and Landspítali.
Key publications
- Karimi et al. (2026). Forearm interface for transfemoral amputees. Biomimetics. doi:10.3390/biomimetics11020112
- Karimi et al. (2025). Haptic systems review. Bioengineering. doi:10.3390/bioengineering12090989
Sensory Substitution
We build vibrotactile and audio-haptic devices that translate visual or auditory information into touch, enabling impaired users to access information they would otherwise miss.
Our cochlear implant project encodes musical rhythms into tactile patterns, reaching 500,000+ CI users worldwide.
Key publications
- Kristjánsson et al. (2026). Sensory substitution through vibrotactile stimulation. In Mobility of Visually Impaired People, Springer. doi:10.1007/978-3-031-91550-5_8
- Yeganeh et al. (2022). Vibrotactile sleeve for cochlear implant users. ASME IMECE. doi:10.1115/imece2022-95591
Spatial Audio & HRTFs
We manufacture silicone pinna replicas with systematically varied geometry, altering one feature at a time to isolate its acoustic contribution. We also train machine learning models to predict HRTFs from ear photographs.
Our open Viking HRTF Dataset v2 — 1513 positions, 20 pinna replicas — is used by researchers worldwide.
Key publications
- Sumner et al. (2025). Synthetic pinnæ for HRTF research. Cogent Engineering. doi:10.1080/23311916.2025.2536150
- Fernández et al. (2023). HRTF prediction with ML. Acoustics. doi:10.3390/acoustics5010015
- Spagnol et al. (2020). Viking HRTF Dataset v2. Zenodo. doi:10.5281/zenodo.4160401
Room Acoustics Simulation
Our structure-preserving model order reduction achieves a 100× speedup in wave-based acoustic simulation while maintaining numerical stability at complex frequency-dependent boundaries.
Developed with Treble Technologies. Funded by RANNÍS.
Key publications
- Bonthu et al. (2026). Stable model reduction for room acoustics. Int. J. Numerical Methods in Engineering. doi:10.1002/nme.70295
Attention, Foraging & Haptic Illusions
We study how synchrony, cross-modal cues, and vibrotactile signals guide human multi-target search. Visual synchrony alone dramatically cuts foraging time; a wrist vibration can be nearly as effective as an auditory cue.
We have also documented the haptic intensity order illusion: strong-then-weak vibration order makes the second stimulus feel displaced — overriding the actual direction.
Key publications
- Makarov et al. (2024). Visual & auditory synchrony in foraging. Attention, Perception, & Psychophysics. doi:10.3758/s13414-023-02840-z
- Hoffmann et al. (2019). The intensity order illusion. Journal of Neurophysiology. doi:10.1152/jn.00125.2019