Abstract: A headset for operably disposing speakers and a visual display on the head of a wearer. The headset includes a beam extending over the vertex of the head for contacting the brow at one end and cooperating with a nape strap on the posterior end for adjusting the fit. Rigid arms extend from the posterior end adjacent the head to terminate in the vicinity of the ears. The arms include compressible compensators to substantially accommodate any size head therein. A visor is pivotally connected to the support beam adjacent the brow piece. The attachment of the visor to the support beam permits the visor to be disposed in a donning position away from the face or an operable position adjacent the face, without requiring a weight bearing surface on the face.

Abstract: An impedance measurement system including a series circuit having a reference impedance leg and a measurement leg, the measurement leg including first and second spaced apart electrodes defining a region for receiving a sample of material to be tested; an oscillator circuit connected in parallel with the series circuit and providing a reference voltage and a signal voltage proportioned to the impedance of the measurement leg; and a detector circuit producing an output voltage proportional to changes between the reference voltage and the signal voltage.

Abstract: A low cost head tracker for a virtual reality head set for determining the orientation of the head set relative to the earth's magnetic field includes a magnetic sensor responsive to the earth's magnetic field, and disposed on the head set and arranged with respect to a vertical axis of rotation of the head set to produce a displacement signal relative to the angular displacement of the head set with respect to a calibration orientation relative to the earth's magnetic field, and a signal processor connected to the magnetic sensor, and responsive to the electrical displacement signal for producing an output signal proportional to the orientation of the head set relative to the calibration orientation.

Abstract: An improved apparatus for the "on-line" measurement of the dielectric constant or percent moisture of a material such as tobacco moving within the walls of a pipe or chute is disclosed. A differential capacitive technique is used for the measurement. The apparatus consists of a four electrode device, with two of the electrodes attached to the outside of the walls of the pipe or chute, and two of the electrodes attached to the inside of the walls of the pipe or chute. The two inner electrodes are connected by switches to the two outer electrodes, respectively, so that first and second capacitances appear at the output terminals of the electrode device depending upon the position of the switches. The output terminals of the electrode device are connected to an oscillator which produces an output signal indicative of the frequency of the oscillator's oscillation which is proportional to the capacitance at the terminals of the electrode device.

Abstract: An improved method and apparatus for determining the dielectric constant of materials which flow using capacitive techniques, having an electrode device with at least two output terminals and three or more electrodes spaced at fixed distances from one another. At least two of the electrodes are connected through a switch so that first and second capacitances appear at the output terminals of the electrode device depending upon the position of the switch. The output terminals of the electrode device being connected to an oscillator which produces an output signal indicative of the frequency of the oscillator's oscillation which is proportional to the capacitance at the terminals of the electrode device. The output signal of the oscillator is connected to a bi-directional counter or microprocessor which is used to calculate a value proportional to the change in capacitance of the electrode device when the switch is closed and to thereby determine the dielectric constant of a material being tested.