Device and method for measuring a rotational frequency of a movable game device

Abstract

For measuring the rotational frequency of a movable game device, one resorts to an existing radio signal in the form of a broadcast signal or mobile communication signal within the framework of an open system, or to a radio signal of an evaluation unit within the framework of a closed system, so as to obtain, by means of an antenna having a directivity characteristic, a time-varying radio antenna receive signal which has a low-frequency modulation portion, the frequency of which corresponding to the rotational frequency of the movable game device.

Description

CROSS-REFERENCE TO RELATED APPLICATION [0001] This application claims priority from German Patent Application No. 102005036355.5, which was filed on Jul. 29, 2005, and is incorporated herein by reference in its entirety. BACKGROUND OF THE INVENTION [0002] 1. Field of the Invention [0003] The present invention relates to movable devices and in particular to game devices such as balls, and to concepts for measuring a rotational frequency of a movable game device. [0004] 2. Description of Prior Art [0005] For quite some time, various interest groups have wished to study and understand the sequence of movements of moving objects and / or persons, which requires an exact indication of the object's position in space and time. What is of particular interest here are, among other things, game balls, in particular in commercialized types of sport, such as footballs, or soccer balls, which are highly accelerated in three-dimensional space, as well as tennis or golf balls. The question of who wa...

AI Technical Summary

Benefits of technology

[0020] It is the object of the present invention to provide an efficient, low-cost but nevertheless flexible concept for measuring a rotational frequency of a movable game device.

[0041] Even if no ambient field is present, the inventive detection device may nevertheless operate in a reliable manner when, using the game device which is typically always communicated with an external transmitter via a radio interface, the external transmitter is given the instruction to generate a radio field whose modulation will then simply be measured by the very same antenna of the movable game device with which the movable game device communicates with the external device anyway. Thus, a self-contained system may readily be implemented as an alternative to the open radio system, while no high-energy steps are required within the movable game device. Within a closed system, it is only the external communication device that must transmit energy. When this is done by a clock, or watch, or something similar, then the battery in this clock will need replacing more often. Alternatively, however, one may also take an energy supply line fixedly installed, e.g., at a sports field, so that no battery operation whatsoever will be required. Even if battery operation is still necessary, a battery replacement and, in particular, utilization of accumulators is considerably easier and less costly than if a battery replacement within the ball would become necessary, which is either not possible or may only be accomplished at high expense and at the price of a downtime of the game device if the characteristics of the game device are not to be greatly influenced.

[0047] By setting the predetermined time duration in the receiver devices worn, or carried, by the player, it is thus possible to set the accuracy and / or the range to be detected. For this purpose, no access to the ball itself is required.

[0048] In addition, the use of two signals of different speeds allows to dispense with any complicated and, thus, failure-prone electronics in the ball itself. One only needs to make sure that the ball has a proximity detector which operates in a contact-controlled or non-contact manner and which will then control the transmission of the two signals of different delay times. Thus, no complicated electronics are required within the ball itself, which is a considerable advantage in particular since the forces and accelerations acting on the ball may be huge, so that there is a very rough environment for there to be an electronic system within the ball.

[0049] On the receiver side, no personal identification or the like is required, which is of considerable advantage—particularly if one considers that what is dealt with here is a mass product, i.e. that may players are to be provided with receiver devices—since thus, all receiver devices may operate in an identical manner and do not require any specific identification, which also renders the receiver devices simple and low in or even completely free from maintenance. In addition, a simple and robust structure also ensures safety from tampering.

Problems solved by technology

The technical means employed so far—mainly cameras—either completely fail to meet the requirements set forth above, or meet them only to an insufficient degree; also the methods, hitherto known, for position finding by means of various transmitter and receiver combinations still leave a large error margin with regard to the spatial resolution of the position indication, with regard to the ease of use of the transmitter / receiver components required, and above all with regard to evaluating the data obtained by means of the transmitter / receiver system, so that it is not yet possible, or at least requires a large amount of effort, to evaluate the results obtained from this data as fast as possible.

What is problematic about such speed measurements which may occur by optical methods is the fact that they do not function within an environment where there is a muddle of players, such as on a football pitch where there are not only two persons being active, but 22 persons, who, in addition—unlike in tennis for a serve—are not positioned in more or less the same place but may form any constellation on the pitch.

Due to the difficulty of the continuously changing constellations in dynamic games, in particular team games, however also in tennis when no serve is currently played, but the ball is played in one move, external speed measurements will fail, which has lead to the fact that there are currently no shot force detection systems that could be employed in a flexible manner.

On the other hand, for the field of sports, but also for the field of leisure, there is a further limitation resulting from the fact that these fields are highly commercialized.

Due to the relatively high cost associated, a small tennis club would never acquire such a system for training purposes, which applies even more to a private person who wishes to play tennis in a slightly more ambitioned manner in his / her leisure time.

Thus, a so-called “stopped” ball in tennis will hardly continue its direction of flight once it bounces on the ground, but will be highly decelerated and then tend to jump off high and thus contribute to the opponent's confusion.

What is disadvantageous about this concept is the fact that the entire detection is based on the earth's magnetic field which may vary considerably from area to area and thus will lead to a pronounced or weak frequency variation, depending on the intensity of the earth's magnetic field.

In addition, measuring the earth's magnetic field requires a lot of effort, particularly as an oscillator must be provided which additionally must be energized.

This problem is a large one, particularly since this oscillator would have to be arranged within the ball, but replacing batteries within the ball or recharging the ball is problematic, if not impossible.

In addition, this concept of the tuned oscillator is also problematic, with regard to the energy consumption, in that the oscillator must be kept switched on irrespective of whether a rotation is detected, and will thus consume as much valuable battery energy of the ball as in those cases when no rotation is measured.

In addition, provision of an oscillator with a wide tuning range is expensive and problematic particularly for low frequencies, unless one resorts to digital circuits which, however, require a lot more energy than analog circuits while being more prone to defects.

On the other hand, to build analog circuits with oscillation characteristics at low frequencies, these circuits would have to have either high capacitances or high inductances, which in turn contributes to the sensor being expensive, to a large volume required and, possibly, even to a heavy weight of the sensor.

In particular, however, volume, energy consumption and especially also the weight of the sensor are measures which should be kept as small as possible, since a ball without a sensor actually must not differ, with regard to its properties for the player, from a ball having a sensor.

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