Participants of many sports, including baseball, football, soccer, hockey, tennis, and golf, and their coaches, are often interested in knowing the motion characteristics of the object used in a sport, such as the distance, time of flight, speed, height, spin rate, or curve of thrown, kicked, or batted balls and slapped hockey pucks. Typically, the speed of a moving ball is measured using a Doppler radar system. Doppler radar systems determine a moving ball's speed by analyzing radar beams reflected off the ball. Although accurate, these systems are expensive and normally cannot be operated by the athlete whose toss or hit is being measured. For these reasons, systems of this type are generally restricted to organized sport teams. Also, Doppler radar systems are not able to measure the spin rate of the ball of interest or give information about the orientation of surface features of the ball, such as leather seams, finger holes, etc., with respect to the axis of rotation. Spin rate and axis of rotation information is useful for example in optimizing a baseball pitcher's curve ball pitching ability.
Several other methods for measuring the motion characteristics of moving objects have been proposed over the years that rely on devices wholly external to the moving object. Another approach to the problem involves placing a measurement device within the moving object. Four such systems are described in U.S. Pat. No. 4,775,948 issued on Oct. 4, 1988 to Dial et al. entitled "Baseball Having Inherent Speed-Measuring Capabilities", the '948 patent, U.S. Pat. No. 5,526,326 issued on Jun. 11, 1996 to Fekete et al. entitled "Speed Indicating Ball", the '326 patent, U.S. Pat. No. 5,761,096 issued on Jun. 2, 1998 to Zakutin entitled "Speed Sensing Projectile", the '096 patent, and U.S. Pat. No. 5,779,576 issued on Jul. 14, 1998 to Smith, III et al. entitled "Throw Measuring Football", the '576 patent.
The '948 patent involves placing an electronic timer and calculator within the ball. The timer measures the ball's time of flight over a measured distance, and on that basis determines the ball's speed. It then displays the speed on the surface of the ball via a liquid crystal display. The '326 patent suggests that a more economical and durable method of accomplishing the same task is met by using mechanical means internal to a ball for determining time of flight and speed. The '096 patent discloses a projectile, such as a baseball, having an inertial switch that opens and closes in response to linear accelerations. An electronic processor connected to the inertial switch calculates speed and displays the results on a visual display on the surface of the ball. The '576 patent discloses an accelerometer in cooperation with a microprocessor within a projectile, such as a football. A liquid crystal display on the surface of the football allows flight characteristics calculated by the microprocessor to be displayed.
None of these systems previously proposed, however, combine the desirable characteristics of being economical, durable, simple to operate by the athlete, and transparent to that athlete in terms of the feel and use of the ball. Also, none of the systems proposed are able to measure the ball's spin rate, curve, or axis of rotation. The embedded electronic timer with a liquid crystal display proposed in the '948, '096, and '576 patents are vulnerable to strikes against the ground, a glove, or a bat. The mechanical solution proposed in the '326 patent claims to be more durable, but alters a ball's physical characteristics even more because of its voluminous design. In addition, it splits a ball into two halves that must be wound relative to each other by the player. The two halves must be held in this position until released in a toss. This design is not transparent to the user and alters the physical structure, balance, and flight performance of a ball significantly. Also, the mechanical design cannot be applied to moving objects that are not held by a player, such as a hockey puck.
It is thus apparent that there is a need in the art for an improved measuring method or apparatus which does not significantly or materially alter the moving object in question's physical characteristics or flight performance, is inexpensive, durable, applicable to many different types of sports equipment and other movable objects, measures many different motion characteristics, and is operable by the person doing the throwing, kicking, hitting, or batting. The present invention meets these and other needs in the art.
This application is a continuation-in-part of application Ser. No. 09/007,241 of Dave Marinelli filed on Jan. 14, 1998 entitled A Speed, Spin Rate, and Curve Measuring Device, which is incorporated herein by reference for all that is disclosed and taught therein.
The present invention improves upon of application Ser. No. 09/007,241 of Dave Marinelli by describing methods of:
(1) reducing the number of g-force proportional sensors required to measure the spin rate of a rotating object through the use of a mixture of mechanical switches and g-force proportional sensors; PA0 (2) reducing the battery power consumed by g-force proportional sensors used to measure the spin rate of a rotating object through the use of a mixture of mechanical switches and g-force proportional sensors. The mechanical switches detect spin. When spin is detected, the g-force sensors are turned on to measure the centrifugal force, from which spin rate and curve can be calculated, and are then turned off. PA0 (3) reducing the number of g-force proportional sensors required to measure flight time and spin rate through the use of new filtering algorithms; PA0 (4) improving the usability of sporting goods projectiles by transmitting motion data immediately after launch; PA0 (5) improving the usability and manufacturability of moving object and monitor pairs by way of an improved identification code mating scheme; and PA0 (6) improving the usability of collected moving object motion data by providing for a means to transfer the motion data to an external computer system for analysis; PA0 (7) providing the user of a spinning object, such as a baseball, information about the orientation of the axis of rotation with respect to markings on the ball such as the leather seams.