Abstract: An electronic system for incorporation in a racquet that monitors a player's ability to hit balls within a specific region on the string bed. A plurality of sensors are positioned around the periphery of the racquet string bed for detecting the relative time-of-arrival of transverse waves produced by impacts of balls on the string bed. A circuit incorporated within the racquet receive the signals from the sensors and provide a plurality of signals from which the position of impact on the string bed may be calculated. The system incorporates a low power microprocessor that is programmed to compute the ball impact location from the signals produced by the sensors. A display device on the racquet displays information derived from the calculated impact location to permit players to assess their performance as related to hitting a predetermined region.

Abstract: The present invention generally relates to a system for use in determining the location and orientation of concealed underground objects and, more particularly, to an improved locator system having a unique and improved interface with an operator. In accordance with one embodiment of the invention, a magnetic field detector for locating concealed underground objects is provided. The magnetic field detector includes a housing having an upper housing portion and a lower housing portion. A receiver is disposed within said housing for receiving magnetic field signals from the concealed underground objects. A swivel joint couples the upper housing portion and the lower housing portion to permit relative rotational motion.

Abstract: An improved locator system is provided which simultaneously couples a number of different frequency signals to a number of concealed underground conductive lines, for the purpose of locating and distinguishing between the underground lines. The locator system includes a transmitter which generates the different frequency signals for coupling to the underground lines. A receiver is also provided that detects the different frequency signals and distinguishes between the underground lines. The locator system further provides an arrangement for operating at virtually any frequency within the locating band, and for preselecting an operating frequency that avoids interference from extraneous signals.

Abstract: An improved locator system is provided which transmits digital and analog information over an electromagnetic field that is radiating from an underground source. The locator system includes a transmitter that modulates its output signal by turning its output signal on and off in response to a sequence of digital words. The transmitter also modulates an analog signal onto the transmitted signal. The modulated analog signal can include an audio frequency or voice signal. The improved locator system also includes a receiver that senses and detects the transmitted digital or analog signal impressed on the radiated electromagnetic field. The receiver also demodulates the transmitted audio frequency signal and provides an audio output signal to an operator.

Abstract: The present invention generally relates to a system for use in determining the location and orientation of concealed underground objects and, more particularly, to an improved locator system having a unique and improved interface with an operator. In accordance with one embodiment of the invention, a magnetic field detector for locating concealed underground objects is provided. The magnetic field detector includes a housing having an upper housing portion and a lower housing portion. A receiver is disposed within said housing for receiving magnetic field signals from the concealed underground objects. A swivel joint couples the upper housing portion and the lower housing portion to permit relative rotational motion.

Abstract: A roll sensor is provided for determining the roll angle of a rotatable member. The roll sensor includes a plurality of elements arranged in a predetermined manner, each element having a first state and a second state. A controller controls the respective state of the plurality of elements. A detector detects an output of the elements which are in the first state. A liquid responsive to the rotation of the rotatable member causes the output of at least one of the elements in the first state detected by the detector to be different than the output of the remaining elements in the first state detected by the detector to determine the roll angle of the rotatable member.

Abstract: An angle sensor for determining the roll angle of a rotating member is provided. The angle sensor includes an array of paired electrical components, each electrical component having an electrical characteristic which varies as a function of temperature. A fluid responsive to the rotation of the rotating member causes the electrical characteristic of a first one of each pair of electrical components to be different than the electrical characteristic of a second one of each pair of electrical components. A comparator compares the electrical characteristics of the first and second ones of each pair of electrical components to determine the roll angle of the rotatable member.

Abstract: An automatic telephone number dialing service for use with mass-distribution media products to enable consumers to automatically dial a preprogrammed number associated with one or more sources of goods and/or services. The device may be constructed as an insert for, or attachment to, various media such as magazines, books, direct mail advertising, newspapers and the like. The device may also be constructed as a customized service card for accessing sources of products or services. The preprogrammed number may be that of a centralized, automated, or personal telemarketing system. The dialing device includes a single chip microprocessor capable of producing DTMF tones corresponding to the preprogrammed telephone. By passing the tones through a miniature speaker or other sound transducer, the preprogrammed number will be automatically dialed. A related telemarketing process using the device is also disclosed.