Development of the Motion-Controllable Ball
Takashi Ichikawa, Takuya Nojima
The University of Electro-Communications Graduate School of Information Systems
1-5-1, Chofu-gaoka, Chofu, Tokyo, Japanichikawa@vogue.is.uec.ac.jp, tnojima@computer.org
ABSTRACTRELATED WORKSIn this report, we propose a novel ball type interactive
interface device. Balls are one of the most important pieces ofequipment used for entertainment and sports. Their motion
guides a player's response in terms of, for example, a feint orsimilar movement. Many kinds of breaking ball throws havebeen developed for various sports(e.g. baseball). However,acquiring the skill to appropriately react to these breaking
balls is often hard to achieve and requires long-term training.
Many researchers focus on the ball itself and have developed
interactive balls with visual and acoustic feedbacks. However,these balls do not have the ability for motion control. In thispaper, we introduce a ball-type motion control interface
device. It is composed of a ball and an air-pressure tank tochange its vector using gas ejection. We conducted anexperiment that measures the ball’s flight path whilesubjected to gas ejection and the results showed the prototype
system had enough power to change the ball’s vector.

Much research has been carried out on ball-type interfaces.
For example, Izuta et al. developed a ball called the“Bouncing Star” [1]. It is a rubber ball for sport that isequipped with LEDs, a wireless module and various sensors.
It can control the LED’s color by the action of the ball as
detected by various sensors.
Tsukada et al. developed a ball called the “ChameleonBall” [5]. It is an acrylic ball that is equipped with a color
sensor, a proximity sensor and LEDs. The color sensor reads
the color of the object that is detected by the proximity sensor
and changes the ball’s color to the same color as the object.
Gili et al. developed a ball called “The Embroidered MusicalBall” [2]. It is a soft ball that has an embroidered pressure
sensor inside it. It can emit various sounds from a PC bysimple physical gestures such as squeezing and stretching.
These studies enabled new types of interactions with balls,
but the techniques were limited to visual or auditory effects(e.g. changing color or generating sounds). Focusing on themotion of the ball will generate a novel way to interact withballs. Therefore, we propose a ball that changes its vector.

Keywords: Ball interface, augmented sports, air pressure
ACM Classifications: H5.2 [Information interface andpresentation]: User Interfaces.

THE BALL THAT CHANGES ITS MOTION VECTOR

In ball sports, the presence of a breaking ball generates aplaying strategy between players and makes the ball sport
more interesting. For example, breaking balls (e.g. a forkball,curveball, etc.) that exist in baseball generate interactive
strategies between the pitcher and batter. However,aerodynamic components that generate a breaking ball mainly
depend on the speed of the pitched ball. If it is slow, the ballcannot generate a major change of vector. In addition, thedesired change of vector is hard to control because it requires
long-term training. Therefore at present it is possible tochange the vector of the ball only in limited situations. In thispaper, we suggest that it is easy to generate a vectorial change
in a ball’s flight. More precisely, we suggest its vector can bechanged without special training. Once this method isestablished, the ball that changes its vector can be used forvarious situations. Some examples follow.

General terms: Experimentation, Human Factors
INTRODUCTION

Balls have been developed and used for various sports andgames since ancient times. In recent years, the progress ininteractive technology has enabled us to develop
nontraditional balls, which are equipped with various sensors
and displays [1]-[5]. In these studies, balls are represented byvisual and acoustic media and produce new and intuitiveinteractions that use the change of a ball’s color and theoutput of a sound. However, these studies have not referred tothe motion of the ball. Many ball players intuitively react tothe ball trajectory. this means the motion of the ball is an
important source of information for ball game players. For
example, a breaking ball can demand a certain strategy fromthe ball thrower. The goal of the motion-controllable ballproject is to develop a ball that can change its vector by
unexpected or expected timing for the opponents. Such a ballshould provide us with a new way for humans to interact. In
this paper, we suggest applications and introduce a prototype.

Dodgeball with vectorial change of ballDodgeball is a ball sport in which players participate bothoutside and inside the court, and that involves hitting a ball toan opponent inside the court. Players can pass the ballbetween the outside and inside of the court through the insidecourt of opponent’s team. If the vector of the ball is changed,
the ball can hit the opponent with unexpected timing.

Copyright is held by the author/owner(s).
UIST’10, October 3–6, 2010, New York, New York, USA.
ACM 978-1-4503-0271-5/10/10..

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Outlet andservomotor

Figure 1: Dodgeball with vectorial change of ball. We
can pretend to pass the ball to a teammate and hit theball to an opponent.

Inlet

Figure 3: Prototype (left) and the tank (right).

We measured the flight distance of the prototype. We filled
the tank of the prototype with gas and hung it up by a string(as in Figure 3). In this configuration, we ejected gas from thetank. The gas ejection caused flight of about one meter
parallel to the ground. This flight was caused only by the gas
ejection; therefore it was adequate for changing the ball’svector by gas ejection while the ball is flying. From thisresult, we confirmed that it was possible to change the ball’svector using the prototype system as indicated.

Adjustment for difference in ability

In a ball sport (e.g. baseball, dodgeball), if the difference inability between the teams is great, this system may havepotential to reduce this difference in ability by permitting
only one team to change the ball’s vector.
SYSTEM

The assumed condition (e.g. usage environment) materiallyaffects the system. For example, if we use a ball that rolls on
the ground, we need to construct a system that considers therotation of the ball and the force that arises between the balland ground. In this paper, we suggest a method that focuses
on a “ball moving through the air at low speed”.
In this study, to create a vectorial change, we use the injectedpressure of gas stored in a tank within the ball.
Apart from the outlet, a button that opens and controls theoutlet is attached. The control of the injected gas is achievedby holding the button down using a servomotor attached to it.
Figure 2 shows the system structure.

CONCLUSION AND FUTURE WORKIn this paper, we proposed a ball whose vector is changed bygas ejection from a tank within the ball. We measured theflight distance of the prototype and confirmed the possibilityof a vectorial change. However, our system does not yet havethe ability to allow control of the vector by the player. Thecontrol of the vectorial change is random at this time.
In the future, we will improve the gas ejection system anddevelop a control system for the vectorial change of the ball.
We also plan to install image recognition technology andother sensors, like accelerometers and gyrometers, to be usedin the control system.

BallTank
Inlet

REFERENCE

1. Osamu Izuta, Toshiki Sato, Haruko Mamiya, Kaoru
Shibasaki, Jun Nakamura, Sachiko Kodama, Hideki
Koike, BouncingStar: Development of a Rubber Ball
Containing Electronic Devices for Digital Sports,
Proceedings of WISS 2008, Japan, 2008, pp.41-44.

Outlet andservomotor

Figure 2: The structure of the prototype system. A ballfor random change of its vector creates by single-shotsof gas ejection.

2. Gili Weinberg, Maggie Orth, Peter Russo, The
Embroidered Musical Ball: A Squeezable Instrument for
Expressive Performance, CHI’00, The Netherlands, 2000,283-284.

In the future, a method to affect the change in direction of theball during a ball game is necessary, for example, push thebutton on the ball to eject gas a few seconds later, recognize agesture of a player inside the playing field, receive anindication of a player outside the playing field, and so on.
These methods must be proposed along with the game design
because they should differ from game to game.

3. Ryota Kuwakubo “HeavenSeed” is described in his website. Ryota Kuwakubo’s site: http://www.vector-scan.com/
4. Yoshiro Sugano, Jumpeo Ohtsuji, Toshiya Usui, Yuya
Mochizuki, Naohito Okude, SHOOTBALL: The Ball
Sport Using Dynamic Goals. ACE 2007, Austria, 2007, pp.
262-263.

PROTOTYPE AND EXPERIMENTATION

To confirm the viability of the above system, we made a
prototype. The ball’s diameter is 16cm and the device weighs
500g. The ball used was a Phlat Ball from Tucker Toys Inc.,and the tank used the long magazine from a toy gun, theWalther P99 from MARUZEN. Figure 3 shows the prototypesof the device and tank.

5. Koji Tsukada, Maho Oki, Chamelleon Ball, Proceedings ofInteraction 2009, Japan, 2009, pp.119-120.

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