Tiny springs keep Wii, PS3 under control
POSTED: 10:24 a.m. EST, November 20, 2006
NEW YORK
(AP) -- With a tilt of your wrists, the dragon you're riding dives
toward the water below. With another movement of your hands, as if
pulling back on imaginary reins, the scaly beast pulls out of the dive
into level flight, flapping its wings.
That's how the unreleased
game "Lair" will work on the Sony PlayStation 3, which launched in the
U.S. on Friday. Like Nintendo Co.'s Wii console, which went on sale two
days later, it uses a motion-sensitive controller in an effort to make
games more intuitive to play.
The controllers make a higher level
of realism possible, too: in the sports game bundled with the Wii in
the U.S., the stick-shaped controller doubles as the handle of a
virtual tennis racket or golf club.
The technology behind
motion-sensing has been around for a while, but recent technical
advances have radically brought down the price -- and the size. The new
game controllers are the first gadgets that promise to bring the
technology into the hands of millions of people, and manufacturers are
now using motion sensors in other consumer products, including cell
phones.
The technology is a wonder of miniaturization and
precision. Here's how Benedetto Vigna, head of the unit at
Switzerland-based STMicroelectronics NV, which makes a motion-sensing
chip for Nintendo, explains how it works:
When you wave around
the new Nintendo controller, two tiny, flat pieces of silicon inside
it, each weighing about a millionth of a gram, flex against silicon
springs that hold them in place.
The movements are minute, or to put it another way, they're on the scale of 10 to 100 hydrogen atoms stacked side by side.
But
these tiny movements can be measured with incredible accuracy. A charge
is applied between the moving pieces of silicon and two nearby sensors.
Faint fluctuations in that charge, as small as that of 10 electrons,
are picked up by a chip that translates it into an understanding of how
the controller is moving.
The two moving weights, which fit
together on an area less than a millimeter square, have different
roles. One has two sets of springs, which allow it to move from side to
side and back and forth. The other weight is a flat piece anchored
almost like trampoline. It senses vertical movement. This way, the chip
can distinguish motion in all three dimensions of space.
Analog
Devices Inc. of Norwood, Massachusetts makes a similar chip, which goes
into the main Wii controller, the stick-like Wii Remote. According to
Analog Devices, ST's chip is used in the auxiliary Freestyle controller
(popularly known as the "Nunchuck") that connects to the larger
controller for some games. ST said it was not allowed to say where
exactly its chip is used.
Sony Corp.'s "Sixaxis" controller for
the PS3 also has an accelerometer. The six axises the name refers to
are the three dimensions of space, plus three axises of spin. The
company hasn't revealed who makes the chip.
The Nintendo Wii
Remote one-ups the Sony controller by including an infrared camera. It
picks up signals from a sensor bar the owner attaches to the television
set. This enables the remote to "know" where it is in relation to the
screen, so the player can use the controller to point to things on the
screen -- a useful feature in shooting games (and a lot of games are
shooting games).
So where has this technology been until now?
Accelerometers
have been used to guide missiles and aircraft, said Richard Marks, who
worked on an underwater robot before his job as head of special
projects at Sony Computer Entertainment America.
"We had a
$25,000 inertial system that was probably comparable," to the one in
the Sony controller, he said. "These things have become so much less
expensive."
In the past, accelerometers were large mechanical
devices, with springs or liquids that sensed orientation and movement.
The reason they can go into game devices now is that they're made not
by assembling mechanical components, but with the same techniques used
to make computer chips.
Vigna described a method of successively
adding and etching away layers of silicon on large platters with
hundreds of individual chips to build up the mechanical part of the
accelerometer. The platters are then broken up into individual chips.
That means the chips can be made consistently and cheaply with
precision down to the micron -- one millionth of a meter, or about one
hundredth of the width of a human hair.
Other so-called
microelectromechanical systems, or MEMS, that are made in similar ways
include chips in video projectors (where they flip thousands of tiny
mirrors to build up the image) and in inkjet heads. MEMS technology is
seen as a fertile field and is related to another hyped area,
nanotechnology (which deals with even smaller scales).
The auto
industry started using silicon accelerometers in the late 1980s for the
sensors that activate air bags, Vigna said, and each successive
generation since then has become smaller and cheaper.
"What ST is doing now is bringing this from the automotive industry to the consumer," Vigna said.
ST says their chip now costs "less than $1 per axis," but wouldn't say exactly what Nintendo is paying.
Accelerometers
have made their appearance in game equipment before. In the late 1990s,
Microsoft Corp. put out a game controller with a limited "tilt"
function, but it never did well. In 2001, Nintendo released a Game Boy
Color cartridge that sensed motion, but it worked only for the included
game.
But with the Sony and Nintendo controller, accelerometers look set for a breakout in consumer devices.
Laptop
makers, including Sony, Lenovo Group Ltd. and Apple Computer Inc., are
using them to detect when a computer is in free fall. This signals the
read/write heads of the hard drive to park, preventing damage when the
laptop lands.
ST has big hopes for the cell-phone market, and is in talks with three phone manufacturers, according to Vigna.
Nokia
this year launched a "sports" cell phone, the 5500, with an
accelerometer that not only controls a game, but works as a pedometer
as well. Other potential uses for such a chip in a phone include
managing the user interface: pat the phone or flip it over to send a
call to voicemail, Vigna suggested.
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