Mudpad: Fluid Haptics for Touch Surfaces

What is MudPad?

Our main objective is to explore the possibilities given by localized active haptic feedback on a touch surface.

Since the introduction of the iPhone touchscreens became very common and most people probably have used one by now. While using a touchscreen is often described as enjoyable due to direct interaction techniques, such screens also lack tactile feedback.

Over the last couple years a few mobile phones with tactile feedback were released. But as of yet they only provide feedback in a global manner applied to the whole screen. Recently, first prototypes with localized tactile texture displays were presented such as TeslaTouch by Olivier Bau et al. and also by companies such as Toshiba and Nokia.

With MudPad, we take a different approach and introduce a device which is able to give localized active haptic feedback by using magnetorheological (MR) fluid and an array of electromagnets to actuate the fluid. The fluid is "smart" because one of its properties - its viscosity - can be controlled by a magnetic field. MudPad is covered by a pouch filled with MR fluid.

off state: free flowing particles

It consists of carbonyl iron powder dissolved in glycerin. The viscosity of this fluid, when in off state, depends on the percentage of iron powder but is generally rather low (comparable to oil). When it is exposed to a magnetic field it immediately turns stiff.

on state with aligned particles

The reaction time of the fluid is within 2ms thereby making it suitable for real-time interactions.

The current prototype is built on 84 electromagnets that are arranged in a 12x7 array. Each magnet can be controlled individually to create a tactile sensation at that specific location only.

Pictures

Tablet sized prototype of MudPad

Array of electromagnets

Small scale prototype of MudPad (one button controlled by one magnet)

People involved

• Yvonne Jansen

Supervised by

• Thorsten Karrer
• Prof. Jan Borchers
• Prof. Martina Ziefle

Publications

2011

• Yvonne Jansen, Thorsten Karrer and Jan Borchers. MudPad: Tactile Feedback for Touch Surfaces.  In CHI '11: Extended Abstracts of the twenty-ninth annual SIGCHI conference on Human factors in computing systems, pages 323–328, ACM Press, New York, NY, USA, May 2011.
  
• Yvonne Jansen. MudPad---Localized Tactile Feedback on Multi Touch Surfaces. Diploma Thesis, RWTH Aachen University, Aachen, March 2011.
  

2010

• Yvonne Jansen, Thorsten Karrer and Jan Borchers. MudPad: Tactile Feedback and Haptic Texture Overlay for Touch Surfaces.  In ITS '10: Proceedings of the ACM International Conference on Interactive Tabletops and Surfaces, pages 11–14, ACM, New York, NY, USA, November 2010.
  
• Yvonne Jansen, Thorsten Karrer and Jan Borchers. MudPad - A Tactile Memory Game.  In ITS '10: Adjunct Proceedings of the ACM International Conference on Interactive Tabletops and Surfaces, pages 306–306, ACM, New York, NY, USA, November 2010.
  
• Yvonne Jansen, Thorsten Karrer and Jan Borchers. MudPad: Localized Tactile Feedback on Touch Surfaces.  In UIST '10: Adjunct proceedings of the 23nd annual ACM Symposium on User Interface Software and Technology, pages 385–386,New York, NY, October 2010.
  
• Yvonne Jansen. Mudpad: Fluid Haptics for Multitouch Surfaces.  In CHI '10: Extended Abstracts on Human Factors in Computing Systems, pages 4351–4356, ACM Press, New York, NY, USA, April 2010.
  

Demonstrations

2010

• Ars Electronica, Sep. 2-4, Linz, Austria.
• UIST 2010. 23rd ACM Symposium on User Interface Software and Technology. Oct. 3-6, New York, NY, USA.