Charles Hendee

IMPAD: an inexpensive multi-touchpressure acquisition device

Recently, there has been great interest in multi-touch interfaces. These have taken the form of optical systems such as Microsoft Surface and Perceptive Pixels 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.

Mechanical force redistribution: enabling seamless, large-format, high-accuracy surface interaction

We present Mechanical Force Redistribution (MFR): a method of sensing which creates an anti-aliased image of forces applied to a surface. This technique mechanically focuses the force from a surface onto adjacent discrete forcels (force sensing cells) by way of protrusions (small bumps or pegs), allowing for high-accuracy interpolation between adjacent discrete forcels. MFR works with any force transducing technique or material, including force variable resistive inks, piezoelectric materials and capacitive force plates. MFR sensors can be tiled such that the signal is continuous across contiguous tiles. By minimizing active materials and computational complexity, MFR makes large-format interactive walls, collaborative tabletops and high-resolution floor tiles possible and economically feasible.

The UnMousePad: the future of touch sensing

Multi-touch input has been an active area of research for over two decades but has always suffered from the absence of an easily available high quality touch input device. For this reason, exciting user interfaces developed in the lab have appeared on CNN, but not on everyones desk, computer screens, table-tops, walls and floors. What has been needed - and lacking - is a better mousetrap; an inexpensive, flexible and sensitive touch imaging technology.

Mechanical force redistribution floor tiles

We present Mechanical Force Redistribution (MFR) Floor Tiles: a method of sensing which creates a seamless, anti-aliased image of forces applied to a floor. This technique mechanically focuses the force from a surface onto adjacent discrete forcels (force sensing cells) by way of protrusions (small bumps or pegs), allowing for high-accuracy interpolation between adjacent discrete forcels. By minimizing active materials and computational complexity, MFR makes large-format floor tiles possible and economically feasible.