A multi-player arcade video game platform
with a wireless tangible user interface
Doo-Seop Eom, Taeyoung Kim, Hyunho Jee,
Hyoil Lee, and Junghyun Han
IEEE Transaction on Consumer Electronics,
Vol. 54, No. 4
November, 2008
Presented by: Chin-Yu, Ou
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Outline
 Introduction
 Arcade Video Game Platform
 Hardware configuration
 Computation of distances and acceleration
 Pose computation
 Performance analysis in position sensing
 Implementation and prototype game
 Conclusion
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Introduction
• A recent game development trend is a natural user
interface which seamlessly integrates physical space
and virtual space.
• Recognition of a game player’s gesture often replaces
traditional pointing devices such a a mouse.
• Tracking a player’s motion, and representing it in
virtual environments.
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Introduction (cont.)
• Authors designed and developed a motion tracking
system using various off-the-shelf wireless sensor
nodes, and built a prototype of an arcade video game.
• The motion tracking system comprised acceleration
sensors and ultrasonic signals.
• The angular velocities of the devices were computed,
to create special effects in the game.
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Hardware configuration
Sink node
Beacon
Game stick
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Hardware configuration (cont.)
• The sink node synchronizes and coordinates the
beacons and game sticks, an then collects the
distance/acceleration data of the game sticks.
• The game sticks send ultrasonic signals to the beacons,
for measuring the distances between them.
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Computation of distances and
acceleration
• The sink node broadcasts RF signals to all game sticks.
• Each game stick responds to the broadcast with an RF
message, which contains its ID.
• The sink node identifies every active game stick.
• The ID of Beacons are known to the sink node in advance.
• When a beacon receives an ultrasonic signal, it uses the
standard time-of-arrival technique to estimate the
distance of the game stick.
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Computation of distances and
acceleration (cont.)
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Computation of distances and
acceleration (cont.)
• Immediately after sending the packet of the last game
stick to the PC, the sink node synchronizes the beacons
and game sticks, and then performs another iteration to
render the next scene.
Packet of each game stick
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Pose computation
• For computing the position of a game stick, the wellknown trilateration method is used.
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Pose computation (cont.)
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Pose computation (cont.)
• The system of equations is solved using NewtonRaphson method.
• 參閱http://math.ntnu.edu.tw/~horng/letter/vol4no6e.htm
運用初始值來求算方程式的近似解，再由近似解代入求
算更精確的解，依此類推。
• The initial position (x, y, z) of the game stick is set to
the center of the game space.
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Performance analysis in position
sensing
• For the purpose of performance analysis, a game stick
was fixed at a particular position, and the distance from
a beacon was measured 1,500 times.
• The distance between the game stick and the beacon is
100cm.
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25ºC
Performance analysis in position
sensing (cont.)
• The speed of sound varies with the atmospheric
conditions, and the most important factor is the
temperature.
• The speed of sound usually increases with increasing
temperature.
• 331.3 (m/s) represents the speed at 0ºC and t is the
temperature.
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Performance analysis in position
sensing (cont.)
• t = 25ºC. The room temp. is 20ºC
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Performance analysis in position
sensing (cont.)
• t = 25ºC. The room temp. is 30ºC
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Implementation and prototype game
• The beacons are located at the four corners of the
screen, and this is a two-player game.
• The ID and pose of each game stick are sampled at
25Hz(motion data of two game sticks are sampled at
50Hz).
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Implementation and prototype game
(cont.)
• For approximating the angular velocities, which are
used for creating special effects in the game.
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Conclusion
• The paper presented an arcade video game platform
that can detect the motions of multiple game players.
• The implementation results proved that various off-theshelf wireless sensor nodes can be used for VR games
that require the tracking of the motions of users or
physical objects.
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