Abstract: A current limiting resistor capable of dissipating power greater than about ¼ Watt is incorporated between the output circuitry of an aftermarket electrical system and an output terminal, so that the output circuitry is protected from excessive currents flowing through the output terminal as a consequence of incorrect connections being made to the output terminal. The resistor has a value of approximately forty Ohms, and a power dissipation rating of three Watts. When correct connections are made, the resistor will permit a current flow from the output terminal of approximately ninety milliAmps through a relay winding, which is sufficient to activate the relay. However, in the case of a miswiring, the resistor will limit the current flow through the output circuitry to no more than about 300 milliAmps.

Abstract: A remote control system which determines which of at least two different vehicle functions to activate based at least in part on the strength of the received signal. In a first alternative embodiment, a strong received signal unlocks the door, whereas a weak received signal causes the engine to start. Thus, using the same signal the driver can start the engine of the vehicle while a distance from the vehicle, and subsequently unlock the door when the driver has walked near to the vehicle. In a second alternative embodiment, the signal to unlock the door is relatively weak when transmitted, whereas the signal to start the engine is relatively strong when transmitted, so that the engine can be started from a distance, but the doors can only be unlocked when the transmitter is near to the vehicle. The security of the vehicle is thereby enhanced, and the ease of use of the remote control system is increased.

Abstract: An alarm system having a signal evaluator is disclosed. The system includes an alarm controller and at least one sensor that generates a signal that corresponds to the magnitude of a detected event. The signal evaluator is part of the controller and receives the magnitude signal from the sensor. The signal evaluator compares the magnitude signal to an alarm threshold and generates an alarm signal if the magnitude signal exceeds the alarm threshold. If not, the signal evaluator compares the magnitude signal to a warning threshold and generates a warning signal if the magnitude signal exceeds the warning threshold and is less than the alarm threshold. The signal generated by the signal evaluator is coupled to an alarm annunciator which generates an alarm in response to the alarm signal and a warning in response to the warning signal. The warning and alarm may be vocal, a siren, or a chirp.

Abstract: A passive arming vehicle alarm system has a valet mode which is activated or deactivated by wireless remote control, thus avoiding the need for hiding a valet switch in the vehicle and subjecting the vehicle to attack at the valet switch. The wireless remote control is also used deactivate the alarm when the alarm is sounding, by depressing any of the buttons on the wireless remote control, regardless of the primary function of the button. As a result, the alarm may be quickly deactivated. The alarm also features progressive passive arming; the alarm emits a brief signal such as a siren chirp as a warning, prior to passively self-arming. As a result, the owner/operator will be warned that the vehicle is about to passively arm and may prevent passive arming (e.g., by opening a door) if it is undesired.

Abstract: An aftermarket mechanical shock detector for mounting to protected property containing an existing alarm system. The shock detector incorporates a piezoelectric transducer detecting mechanical vibration and generating an electrical vibration signal, and circuitry for comparing the vibration signal to thresholds. The shock detector includes two separately adjustable thresholds. If the vibration signal exceeds either threshold, the shock detector creates an electrical connection between two terminals, thereby triggering a previously-installed alarm circuit to create an alarm.