Abstract: An activator circuit responsive to power line disturbances. In condition of false alarm, the user will toggle a local light switch causing electrical disturbances on the power line. The activator circuit detects these disturbances and activates an output, which is further connected to the silence function on the detector, silencing the false alarm. The activator circuit comprising a power line interface circuit, a signal conditioning circuit, a threshold detector circuit, a pulse train comparison circuit and an output circuit.

Abstract: A capacitive soil moisture sensor that is easy to install, does not require complex calibration, can sense moisture at a particular depth, can accommodate soils of different composition, does not alter soil densities, provides fast response to changes in moisture and provides stable long term use. The sensor comprising of a body (10) onto which is attached a plurality of first electrode (20) and a plurality of second electrode (30). A plurality of protective layer (50) of low dielectric constant material is applied over the electrodes and against the body (10) to provide a physical barrier to prevent a conduction path from the first electrode (20) to the second electrode (30) and to provide protection against physical damage. The first and second electrodes (20), (30), once inserted into the soil, forms a capacitor with the soil as the dielectric. A change in soil moisture causes the capacitance of the sensor to change.

Abstract: This invention is an apparatus and method for determining the velocity of a projectile. A light curtain unit (20) creates two light curtains (46)(48) and two sensing planes (50)(52). The projectile causes light from the light curtain (46)(48) to be reflected into the detectors (22a) and (24a) of the sensing planes (50)(52). The time for a projectile to pass through one sensing plane to the other is measured and calculated for display by the Display Unit (10).

Abstract: This invention is a system for locating an object. A tag unit (100) that is attached or embedded into the object to be located generates radio frequency signals when excited by an ultrasonic wave (108). The locator unit (100) generates the ultrasonic wave (108) and receives radio frequency signals from the tag unit (110). The locator unit (100) determines the signal strength of the received radio frequency signal and provides a representation of the strength. By monitoring the signal strength indication, the user will be directed to the object.

Abstract: This invention is a system for locating an object. A tag unit (100) that is attached or embedded into the object to be located generates radio frequency signals when excited by an ultrasonic wave (108). The locator unit (100) generates the ultrasonic wave (108) and receives radio frequency signals from the tag unit (110). The locator unit (100) determines the signal strength of the received radio frequency signal and provides a representation of the signal strength. By monitoring the signal strength indication, the user will be directed to the object.