Abstract: Intrusion into an automotive vehicle interior is detected by passing an airborne acoustic signal through a portion of the vehicle interior when the vehicle security system is active, and by measuring any change in phase in the signal as it passes through the vehicle. The phase of a first frequency component in the signal is sensitive to intrusion into the vehicle, and the phase of a second frequency component is sensitive to false alarm conditions, but is not sensitive to intrusion.

Abstract: This invention is directed to a position detection system for a rotary motor element where color is used to determine the position of the rotary motor element. Different color light pulses are emitted in the direction of a color-coded disk which rotates in accordance with the rotary motor element. The light pulses are reflected back from the disk in distinct combinations which define the position of the rotary motor element. By determining which colors of light are reflected back, the position of the motor element may be determined. The apparatus may be located remote from the position detector to extend the life and the reliability of its electronic components. The angular resolution of a range of rotary positions is dependent upon the number of color regions on the color-coded disk and the number of different colors of light pulses that are emitted.