How Touching
From: Economist Technology Quarterly - 03/2007

Although touch screens offer greater versatility for electronic devices, some
people are concerned that these devices are too tricky to use without the
assurance of actually pressing a button. The answer to this problem would be
touch screens that are able to simulate the feel of pressing a button using
haptics technology. Researchers working with haptics have developed a new
method of simulating touch sensations by using "skin stretch" technology. The
sense of touch has been found to rely far more on the way that skin is
stretched than the amount of pressure applied to it. Just as the human eye
can be "tricked" into seeing a range of colors on a TV when there is actually
only red, green, and blue dots, the sense of touch can be tricked into
feeling textures and shapes that are not actually there. A project conducted
by Mexican and Italian researchers showed the ability to make a flat surface
feel as if it were sharp. The researchers connected a thimble to a motorized
arm and sent short bursts of very precise resistance through it, to stretch
the skin of a fingertip laterally as it passes over the thimble. Eventually,
haptics researchers hope to be able to simulate any material, but they must
first find a way to simulate the miniscule ridges in the skin of the
fingertips that interact with a surface, possibly using
micro-electromechanical systems (MEMS) technology, but this technique has not
been attempted yet. One innovation that has been developed is a sliding
button for mobile devices that has haptic feedback capability. A user could
"feel" icons or names as they scroll over them. The researcher responsible
for this technology believes that people can learn to recognize symbols
through touch alone. 

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