Abstract: A batting aid that may easily be installed upon fixed or temporary structures, made up of a main frame that slidably supports a tube which in turn supports a ball for a batter to hit. The ball is fixed to the tube by a wire cable that extends through the ball, and is in turn mounted to the tube. The tube is height adjustable so that batters of differing stature and ages can easily practice upon balls at varied heights. The assembly is strong in construction so that a practicing batter is able to hit the ball hard and not cause damage or require another player to throw balls over the plate or return balls to the batter.

Abstract: A batting aid that may easily be installed upon fixed or temporary structures, made up of a main frame that slidably supports a tube which in turn supports a ball for a batter to hit. The ball is fixed to the tube by a wire cable that extends through the ball, and is in turn mounted to the tube. The tube is height-adjustable so that batters of differing stature and ages can easily practice upon balls at varied heights. The assembly is strong in construction so that a practicing batter is able to hit the ball hard and not cause damage or require another player to throw balls over the plate or return balls to the batter.

Abstract: A self-compensating fluid level sensor is described, including a dual array of capacitive sensors on a dielectric substrate, the dual array of sensors forming multiple sensor pairs. Multiple signal detection circuits including comparators are configured to compare the capacitance of a first sensor pair with a second sensor pair. The internal capacitance comparisons allow the fluid level sensor to compensate for variations in the dielectric of the fluid being measured, as well as for manufacturing and materials variations that affect capacitive sensing. The passive level sensor also provides a platform for providing additional circuitry for providing additional information regarding the liquid, such as liquid composition.

Abstract: A capacitive liquid level indicator having a capacitive sensor array superposed on each side of a dielectric substrate, wherein the sensor signal detection electronics are located immediately adjacent each capacitive sensor. These provisions result in high sensitivity of detection of submergence in the liquid, as well as essentially eliminating parasitic electric fields. The preferred capacitive sensors are interdigitated capacitors, and the preferred sensor signal detection circuit is an RC bridge and a comparator, wherein the comparator senses a voltage difference in the RC bridge between a sensor resistor and sensor capacitor of a first leg thereof and a reference resistor and reference capacitor of a second leg thereof. It is preferred for the capacitive liquid level indicator to be coated with a low dielectric conformal coating to thereby insulate the electronic components (inclusive of the capacitive sensors) thereof with respect to the liquid into which it is submerged.