Anti-car jacking/theft device

• US 5,574,424 A
• Filed: 05/09/1994
• Issued: 11/12/1996
• Est. Priority Date: 05/09/1994
• Status: Expired due to Fees

• Current Assignee: Duc Nguyen
• Original Assignee: Duc Nguyen
• Inventors: Nguyen, Duc M.
• Primary Examiner(s): Swarthout, Brent A.
• Assistant Examiner(s): TONG, NINA C
• Application Number:
  US08/239,573
• Time in Patent Office: 918 Days
• Field of Search: 340/426, 340/427, 340/428, 340/429, 340/430, 340/568, 340/666, 307/10.1, 307/10.2, 307/10.3, 307/10.4, 180/287, 177/1, 177/45, 177/50, 109/7, 109/23, 235/431
• US Class Current: 340/426.11
• CPC Class Codes: B60R 25/1004 Alarm systems characterised by the type of sensor, e.g. current sensing means using door lock sensors B60R25/1001

Abstract

An anti-car jacking/theft device for detecting an unauthorized person who is attempting to operate a vehicle and activating an alarm including a measurement mechanism adapted to be coupled to a driver'"'"'s seat of a vehicle for transmitting an input weight signal indicating a person'"'"'s weight; a key receiving mechanism adapted for receiving a user-supplied key and transmitting a reset signal when the key is activated, a set signal when the key is de-activated, and a key status ready signal having one mode indicating that the key receiving mechanism is active and another mode indicating that the key means is inactive; control circuitry for receiving the input weight signal from the measurement means and the reset signal, set signal, and key status ready signal from the key receiving means, comparing the input weight signal with a resident reference weight signal and a resident input threshold signal with the control circuitry having one mode for transmitting an alarm command signal indicating that an unauthorized weight is detected at the measurement means and another mode for transmitting an alarm command indicating that the key receiving means is inactive; alarm mechanism for receiving the alarm command signal and activating an alarm; and a power source for energizing and de-energizing the measurement circuitry, key receiving circuitry, and control circuitry.

Claims

1. An anti-car jacking/theft device for detecting an unauthorized person who is attempting to operate a vehicle and activating an alarm comprising, in combination:

measurement circuitry adapted to be coupled to a driver'"'"'s seat of the vehicle for transmitting an input weight signal indicating a person'"'"'s weight when a person sits on the driver'"'"'s seat;

key receiving circuitry adapted for receiving a user-supplied key and transmitting a reset signal when the key is coupled therewith, a set signal when the key is de-coupled therefrom, and a key status ready signal having one mode indicating that the key receiving circuitry is active and another mode indicating that the key receiving circuitry is inactive;

control circuitry for receiving the input weight signal from the measurement circuitry and the reset signal, set signal, and key status ready signal from the key receiving circuitry, comparing the input weight signal with a resident reference weight signal and a resident input threshold signal with the control circuitry having one mode for transmitting an alarm command signal indicating that an unauthorized weight is detected at the measurement circuitry and another mode for transmitting the alarm command signal indicating that the key receiving circuitry is inactive, the control circuitry further comprising;

read-only-memory circuitry for receiving and storing the input threshold signal and the input weight signal as the reference weight signal with the read-only-memory circuitry having one mode for transmitting the reference weight signal based on the receipt of the set signal and another mode for transmitting the reference weight signal based on the receipt of the reset signal;

arithmetic circuitry for receiving the input weight signal and reference weight signal and transmitting a weight difference signal based on the absolute difference between the input weight signal and reference weight signal;

inverter circuitry for receiving the reset signal, the set signal, and the key status ready signal and transmitting an inverted reset signal, an inverted set signal, and an inverted key status signal;

comparator circuitry for receiving the input threshold signal, comparing the level of the input threshold signal to the levels of the input weight signal and the weight difference signal, and transmitting a first indication signal and a second indication signal based on the comparisons;

first conjunctive circuitry for receiving the first indication signal and the second indication signal and transmitting a first conjunctive indication signal based on the levels of the first indication signal and the second indication signal;

second conjunctive circuitry having one mode for receiving the first conjunctive indication signal and the inverted reset signal and transmitting a second conjunctive indication signal based on the levels of the first conjunctive indication signal and the inverted reset signal and another mode for receiving the first conjunctive indication signal and the inverted set signal and transmitting a second conjunctive indication signal based on the levels of the first conjunctive indication signal and the inverted set signal;

counter circuitry for receiving the second conjunctive indication signal and transmitting a detection signal provided the second conjunctive indication signal is received for a given period of time; and

selection circuitry for receiving the detection signal and inverted key status ready signal and having one mode for transmitting the alarm command signal when the detection signal is received, whereby indicating that the unauthorized weight is detected at the measurement circuitry, and another mode for transmitting the alarm command signal when the inverted key status ready signal is received, whereby indicating that the key receiving circuitry is inactive;

alarm means for receiving the alarm command signal and activating the alarm;

power transmission means for energizing the measurement circuitry, key receiving circuitry, and control circuitry; and

switch means coupled between the power transmission means and the measurement circuitry, key receiving circuitry, and control circuitry, the switch means having one orientation for activating the measurement circuitry, key receiving circuitry, and control circuitry and another orientation for deactivating the measurement circuitry, key receiving circuitry, and control circuitry.

2. An anti-car jacking/theft device for detecting an unauthorized person who is attempting to operate a vehicle and activating an alarm comprising, in combination:

measurement means adapted to be coupled to a driver'"'"'s seat of the vehicle for transmitting an input weight signal indicating a person'"'"'s weight;

key receiving means adapted for receiving a user-supplied key and transmitting a reset signal when the key is activated and a set signal when the key is de-activated;

control circuitry for receiving the input weight signal from the measurement means and the reset signal and the set signal from the key receiving means, comparing the input weight signal with a resident reference weight signal and a resident input threshold signal and with the control circuitry having one mode for transmitting an alarm command signal indicating that an unauthorized weight is detected at the measurement means when the set signal is being received to thereby signify that the key receiving means is active and another mode for transmitting the alarm command signal when the reset signal is being received to thereby signify that the key receiving means is inactive; and

with the control circuitry including memory circuitry for receiving and storing the reference weight signal, the input threshold signal, and the input weight signal for subsequent use;

alarm means for receiving the alarm command signal and activating an alarm when an unauthorized weight is detected and the key receiving means is active; and

a power source for energizing and de-energizing the measurement circuitry, key receiving circuitry, and control circuitry.