Abstract: A transmitter pen positioning system includes a transmitter pen, at least two photo-receiving modules, and a signal processing unit. The transmitter pen generates a light beam signal. Each photo-receiving module has an optical lens and a photo-receiving sensor. The photo-receiving sensor receives the light beam signal passing through the optical lens via a first photo-receiving surface and a second photo-receiving surface and correspondingly converts the light beam signal into a first photocurrent signal and a second photocurrent signal. The signal processing unit receives the first and the second photocurrent signals, and correspondingly calculates an incident angle of the light beam signal according to a difference between the first and the second photocurrent signals and calculate position information of the transmitter pen according to the at least two incident angles. Accordingly, the complexity of the positioning system is simplified and a real-time position calculation is implemented.

Abstract: Methods and apparatus for using ultrasound to measure speed and acceleration in fluids is provided. Three exemplary embodiments are disclosed. The first exemplary embodiment measures fluid velocity, such as, for example, wind, under standard atmospheric pressure-temperature. The second exemplary embodiment measures gas velocity, such as, for example, wind, affected by and automatically calibrates for pressure-temperature. The third exemplary embodiment measures gas density, such as, for example, density altitude. Applications of the invention include wind direction and speed calculation in agriculture, aviation, hydraulics, and other industries. One of the advantages provided by the invention is there are no moving parts in making such measurements.

Abstract: Methods and apparatus for using ultrasound to measure speed and acceleration in fluids is provided. Three exemplary embodiments are disclosed. The first exemplary embodiment measures fluid velocity, such as, for example, wind, under standard atmospheric pressure-temperature. The second exemplary embodiment measures gas velocity, such as, for example, wind, affected by and automatically calibrates for pressure-temperature. The third exemplary embodiment measures gas density, such as, for example, density altitude. Applications of the invention include wind direction and speed calculation in agriculture, aviation, hydraulics, and other industries. One of the advantages provided by the invention is there are no moving parts in making such measurements.

Abstract: An apparatus and process for using ultrasound to measure speed and acceleration in fluids is provided. Three preferred embodiments are disclosed. The first preferred embodiment measures fluid velocity, such as, for example, wind, under standard atmospheric pressure-temperature. The second preferred embodiment measures gas velocity, such as, for example, wind, affected by and automatically calibrates for pressure-temperature. The third preferred embodiment measures gas density, such as, for example, density altitude. Applications of the invention include wind direction and speed calculation in agriculture, aviation, hydraulics, and other industries. One of the advantages provided by the invention is there are no moving parts in making such measurements.

Abstract: A transmitter pen location system is provided, in which a pen is adapted to send a repeated output signal to external receivers at two or more receiver locations, wherein the location of the pointing tip of the pen is determined in relation to the writing surface of a whiteboard. In one embodiment an output element, preferably an ultrasonic transducer, transmits a time dependent output signal from a single signal transmitter pen to two or more external receivers at two or more receiver locations. The direction of arrival of the output signal to each of the receiver locations is determined, and the pointing tip of the single transmitter pen is then determined, as the intersection of direction vectors from the pen to the external receivers.

Abstract: A transmitter pen positioning system is provided, in which a pen, having multiple output elements, is used to accurately determine the location of the pointing tip of the pen, in relation to the writing area of a surface, such as a white board. The first output element, preferably an infrared transducer, transmits a first output signal from the transmitter pen. The second output element, preferably an ultrasonic transducer, transmits a second output signal, having a lower propagation velocity than the first output signal, from the transmitter pen to two or more receivers. In a basic embodiment, the first output signal arrives at one or more receivers generally concurrently.

Abstract: A transmitter pen positioning system is provided, in which a pen, having multiple output elements, is used to accurately determine the location of the pointing tip of the pen, in relation to the writing area of a surface, such as a white board. The first output element, preferably an infrared transducer, transmits a first output signal from the transmitter pen. The second output element, preferably an ultrasonic transducer, transmits a second output signal, having a lower propagation velocity than the first output signal, from the transmitter pen to two or more receivers. In a basic embodiment, the first output signal arrives at one or more receivers generally concurrently.

Abstract: A transducer signal waveshaping system is provided, in which a signal excitation circuit includes a non-linear device. The resulting circuit produces a short input pulse, which allows a piezoelectric transducer to transmit a shortened output signal having distinct waveshape characteristics. The resulting waveshaped output signal, typically an ultrasonic signal, provides a measurable time-dependent signal that is particularly suited for data entry systems, such as for movable transmitter pens and white boards. The location of the transmitter pen in relation to the writing area of a white board can be determined, using the periodic transmission of the waveshaped output signals. Alternative embodiments include additional circuit elements, which allow the resulting waveshaped output signal to include even more distinctive waveform features.