Bristol Interaction Group


Haptic Feedback Powered by Ultrasound


Ultrahaptics is a system for creating haptic feedback in mid-air. Waves of ultrasound displace the air, creating a pressure difference. By causing many waves to arrive at the same place simultaneously, a noticeable pressure difference is created at that point. With this method, we are able to create multiple, concurrent points of haptic feedback in mid-air.



Graham Wilson, Tom Carter, Sriram Subramanian and Stephen Brewster, Perception of Ultrasonic Haptic Feedback on the Hand: Localisation and Apparent Motion, ACM CHI 14, April 2014.

Tom Carter, Sue Ann Seah, Benjamin Long, Bruce Drinkwater, Sriram Subramanian, Ultrahaptics: Multi-Point Mid-Air Haptic Feedback for Touch Surfaces. UIST’13. October 2013. [PDF, 1.4MB]

Graham Wilson, Euan Freeman, Tom Carter, Sue Ann Seah, Steve Brewster, Sriram Subramanian, Ultrasonic Haptic Feedback for Gestural Interfaces using a Moveable Hand-Mounted Array. IEEE WorldHaptics 2013. (Daejon, Korea)

Marianna Obrist, Sue Ann Seah, and Sriram Subramanian. Talking about tactile experiences. In CHI  2013. pp 1659-1668.[PDF, 1.6MB]

Jason AlexanderMark T. MarshallSriram Subramanian, Adding Haptic Feedback to Mobile TV. Extended Abstracts of the International Conference on Human Factors in Computing Systems. April 2011. [PDF, 289 kB][ACM Digital Library]

Jason AlexanderMark T. MarshallSriram Subramanian, Increasing the Appeal of Mobile TV Using Haptic Feedback. CHI 2011 Workshop on Video Interaction – Making Broadcasting A Successful Social Media. May 2011. [PDF, 63 kB]


Tom CarterMark T. MarshallSriram Subramanian, Ultrahaptics: Creating Haptic Feedback Using Ultrasound. Set For Britain Poster Competition. March 2012. [PDF, 7.6MB]

Jason AlexanderMark T. MarshallSriram Subramanian, Adding Haptic Feedback to Mobile TV. CHI 2011 Work-in-Progress Poster. May 2011. [PDF, 1.5MB]




Creating Focal Points:

  1. Waves of ultrasound displace the air creating a pressure difference. This is called acoustic radiation pressure.
  2. By focussing many ultrasound waves to a point in mid-air, we can create a noticeable pressure difference.
  3. We create a focal point by triggering ultrasound tranducers with specific phase delays so that all sound waves arrive at the point concurrently.

Human Perception of Ultrasound:

We modulate the ultrasound so that it is perceived as a vibration on the skin. Changing the modulation frequency or pulsing the feedback gives different textures. By giving each feedback point a different modulation frequency, we can have different feedback, with different textures applied to the user at the same time.