Abstract: A low power transmitter useful for vehicle remote keyless entry systems, for example, includes a transmitter circuit portion and a gain control circuit portion. The gain control circuit portion preferably includes an inductive load that introduces a resonant frequency that provides radio frequency gain control. The transmitter circuit portion preferably includes a transistor having a collector node and an emitter node. The gain controller circuit preferably includes a capacitive load coupled between the emitter node and the collector node of the transistor. The inductive load preferably is coupled between the emitter node of the transistor and ground.

Abstract: A system for automatically charging a battery of a remote keyless entry transmitter includes a voltage monitoring circuit having a first microprocessor which monitors battery voltage and which causes the transmitter to send an RF signal to a receiver in the form of a base station on a motor vehicle. The signal causes a charging circuit of the base station to activate an inductive field to cause the battery to be fully charged. In one embodiment, the first microprocessor also causes the transmitter to send a second signal to the base station to shut down the charging field when the battery voltage reaches a predetermined upper limit. In another embodiment, a second microprocessor of the base station tracks the charging time and shuts down the charging field when the charging time reaches a predetermined amount. Alternatively, charging can be done by direct contact or other means.

Abstract: A multifunction remote keyless entry system is provided that increases functionality of the transmitter without increasing the size of the transmitter unit by having certain buttons on the transmitter perform multiple functions based on the distance from the vehicle. More specifically, actuation of a button on the portable transmitter unit triggers operation of a first designated function if the transmitter is outside a predetermined range from the vehicle. Actuation of the same button within the predetermined range will trigger operation of a second designated function. Thus, one button performs at least two functions depending on the distance the user is from the vehicle. In a further embodiment, the same button could trigger operation of a set of different functions as a function of multiple, concentric zones around the vehicle.

Abstract: A system for automatically charging a battery of a remote keyless entry transmitter includes a voltage monitoring circuit having a first microprocessor which monitors battery voltage and which causes the transmitter to send an RF signal to a receiver in the form of a base station on a motor vehicle. The signal causes a charging circuit of the base station to activate an inductive field to cause the battery to be fully charged. In one embodiment, the first microprocessor also causes the transmitter to send a second signal to the base station to shut down the charging field when the battery voltage reaches a predetermined upper limit. In another embodiment, a second microprocessor of the base station tracks the charging time and shuts down the charging field when the charging time reaches a predetermined amount. Alternatively, charging can be done by direct contact or other means.

Abstract: An optical anti-theft system incorporates a member having a plurality of reflective surfaces. The plurality forms a pattern corresponding with the security code. The system additionally incorporates a base for receiving the member. The base incorporates a light source for generating a light beam to illuminate the plurality of reflective surfaces, and a light detector for sensing the illuminated plurality of reflective surfaces and for initiating a security function in response to the sensed illuminated plurality of reflective surfaces having the pattern.

Abstract: A moveable body, cladding medium, and fiber are arranged to form a sensor suitable for use in monitoring changes in liquid, fluid, and material level and changes in pressure. The moveable body moves in response to changes in pressure or force. Movement of the body causes a change in the length of cladding medium surrounding an optical fiber. As the extent of cladded fiber length changes, the intensity of light transmitted through the fiber also changes.