The touchy-feely side of telecoms
By Celeste Biever
At the end of March 2005 Samsung will release a mobile phone with a difference.
Not only will it be able to send images and streaming video, but the phone can
vibrate in such a way that you can add the sensation of a playful tickle to your
text message, or make the person on the other end of the phone feel as if their
handset has slapped them across the face. Welcome to the world of haptics - the
technology of recreating touch and texture through artificial stimuli.
The most widespread use of haptics so far is in video gaming, in the vibrating
game pads and force-feedback steering wheels that accompany Sony's PlayStation 2
and Microsoft's Xbox. These devices give you a sense of how good a virtual
golfing shot was from the force feedback on the joystick, or let you feel how
close you are to being run off the road in racing games.
But Samsung's phone is the first mass-market use of haptics. When you send a
text message you can add one of a number of sensations from a menu. When the
person reads the message, "vibrotactile" motors in their phone are activated.
These are basically more complex versions of the motors that allow many mobile
phones to vibrate when ringing. The precise frequency and amplitude of the
vibrations generated by the motors simulates the desired sensation.
"I have been waiting for this for a few years. It's a challenge to develop
systems that are low-cost and lightweight," says Ed Colgate, a mechanical
engineer who works on haptics at Northwestern University in Chicago, US.
Feel the quality
The haptic technology behind game pads and the Samsung phones has been
developed by Immersion of San Jose, California, US, which is one of the leading
companies in this fast-growing field (see graphic). From these simple
beginnings, analysts think the technology will have many applications, for
example, in haptic gloves and pads designed to give online shoppers a feel for
products.
Imagine being able to feel the quality of a cashmere sweater before you buy it,
experience the roadholding of a car or feel the finish of a piece of furniture.
"Physical involvement creates a real attachment and is lacking in online
interactions," says Colgate.
Just like graphics and sound, touch can be coded as digital bits. They are sent
in packets over the internet or a cellphone network then reassembled or
"rendered" in some form at the other end. So why has it taken so long for the
technology to develop?
"Haptics is fundamentally more difficult over the internet than sound or
vision," says Colgate. This is partly because touch encompasses a wide variety
of physical factors including force, vibration, temperature and texture, and
unlike light or sound, it can be sensed over the whole body.
Phantom sensations
But there are ways to simplify the problem. In 1996 three researchers at the
Massachusetts Institute of Technology, US, built a three-jointed robotic arm
called the Phantom that lets you experience the feeling of doing surgery. On the
end of the arm is a stylus that you grip like a pen, and as you manipulate it,
the forces in the arm mimic the sensation of cutting through tendons or placing
a catheter, for example. The Phantom gives medical students experience of
surgery without putting patients at risk.
Another problem is that touch is interactive - you have to press something to
feel it. This two-way quality is difficult to achieve over the internet because
of delays, called latencies, which can mount up and disrupt the interaction.
Although a delay of more than 200 milliseconds may be acceptable for holding a
phone conversation or watching video, touch needs a fairly immediate reaction to
be realistic, says Kenneth Salisbury of Stanford University, California, US, one
of the inventors of the Phantom.
Holding hands
For haptics to reach their full potential, the technology also has to be able to
convey a wide range of tactile sensations. Sile O'Modhrain at Media Lab Europe
in Dublin, Ireland, says that "pre-packaged" haptics have barely scratched the
surface.
For example, a student at MIT has built a phone that can transmit a squeeze of
varying strength. Accelerometers in the phone measure the strength and speed of
the squeeze and reproduce the effect at the other end of the line, making it
feel a bit like holding hands. Much of the technology needed to achieve such
effects already exists, O'Modhrain says.
O'Modhrain has a personal interest in haptics: she happens to be blind. A
touch-based internet could be a real boon, but efforts so far have not been
impressive. They have concentrated on reproducing the raised outline of shapes
such as graphs and pie charts. But as Curtis Chang at the Iowa-based US National
Federation of the Blind in Computer Science points out: "If you grew up blind,
they don't mean anything to you."
http://www.newscientist.com/article.ns?id=dn7049