IMPAD: an inexpensive multi-touchpressure acquisition device

ABSTRACT

Recently, there has been great interest in multi-touch interfaces. These have taken the form of optical systems such as Microsoft Surface and Perceptive Pixel's FTIR display as well as hand-held devices using capacitive sensors such as the Apple iPhone. However, optical systems are inherently bulky while capacitive systems are only practical in small form factors and are limited in their application because they only respond to human touch.

We have created a technology that enables the creation of Inexpensive Multi-Touch Pressure Acquisition Devices (IMPAD) which are paper-thin, flexible and can easily scale down to fit on a portable device or scale up to cover an entire table. These devices can sense varying levels of pressure at a resolution high enough to sense and distinguish multiple fingertips, the tip of a pen or pencil and other objects.

Other potential applications include writing pads, floor mats and entry indicators, bio-pressure sensors, musical instruments, baby monitoring, drafting tables, reconfigurable control panels, inventory tracking, portable electronic devices, hospital beds, construction materials, wheelchairs, sports equipment, sports clothing and tire pressure sensing.

REFERENCES

• 1: Apple iPhone. http://www.apple.com/iphone
• 2: William Buxton , Ralph Hill , Peter Rowley, Issues and techniques in touch-sensitive tablet input, Proceedings of the 12th annual conference on Computer graphics and interactive techniques, p.215-224, July 1985
• 3: Jefferson Y. Han, Low-cost multi-touch sensing through frustrated total internal reflection, Proceedings of the 18th annual ACM symposium on User interface software and technology, October 23-26, 2005, Seattle, WA, USA [doi>10.1145/1095034.1095054]
• 4: JazzMutant Lemur. http://www.jazzmutant.com
• 5: Microsoft Surface. http://www.surface.com
• 6: Tekscan. http://www.tekscan.com
• 7: Wayne Westerman. Hand Tracking, Finger Identification and Chordic Manipulation on a Multi-Touch Surface. PhD thesis, University of Delaware. (1999)

INDEX TERMS

Primary Classification:
  H. Information Systems
  H.5 INFORMATION INTERFACES AND PRESENTATION (I.7)
      H.5.2 User Interfaces (D.2.2, H.1.2, I.3.6)
          Subjects: Input devices and strategies (e.g., mouse, touchscreen)

General Terms:
Algorithms, Design, Human Factors

Keywords:
bilinear, flexible, fsr, input device, lotus, multi-touch, pressure, sensor