Vehicle security system

Details Vehicle security system Vehicle security system

2002-01-07

2003-08-19

Wu, Daniel J. (Department: 2632)

Communications: electrical

Land vehicle alarms or indicators

Internal alarm or indicator responsive to a condition of the...

C340S315000, C340S428000, C340S441000, C307S010200

Reexamination Certificate

active

06608555

ABSTRACT:

CROSS-REFERENCE TO RELATED APPLICATION
This application claims priority of Taiwanese application. no. 90219607, filed on Nov. 14, 2001.
BACKGROUND OF THE INVENTION
1. Field of the Invention
The invention relates to a vehicle security system, more particularly to one using alternating current signal transmission through a power supply line.
2. Description of the Related Art
Most vehicles are currently equipped with a vehicle security system in order to guard against vehicle theft.
FIG. 1
illustrates a vehicle
2
equipped with a conventional vehicle security system
1
. The conventional vehicle security system
1
comprises a host device
10
that controls all anti-theft operations, a detector circuit cluster
11
that detects different conditions of vehicle theft, and an alarm circuit cluster
12
.
The detector circuit cluster
11
is connected to the host device
10
and is adapted to detect a current status of different components of the vehicle
2
for detecting signs of vehicle theft. The detector circuit cluster
11
includes an engine hood detector circuit
111
adapted to detect unauthorized opening of an engine hood
21
of the vehicle
2
, a trunk hood detector circuit
112
adapted to detect unauthorized opening of a trunk hood
22
of the vehicle
2
, a hand brake detector circuit
113
adapted to detect unauthorized movement of a hand brake
231
of the vehicle
2
, door detector circuits
114
adapted to detect unauthorized opening of doors
24
of the vehicle
2
, and a lock-pick detector circuit
115
adapted to detect insertion of a lock-pick into an ignition keyhole
25
of the vehicle
2
. The conventional detector circuits
111
-
115
included in the detector circuit cluster
11
are in the form of switches that open and close in accordance with the current status of the respective component of the vehicle
2
. Because each detector circuit
111
-
115
is connected to a voltage source, the host device
10
can determine the presence of unauthorized operation of the vehicle
2
by monitoring the voltage signals from the detector circuits
111
-
115
.
The alarm circuit cluster
12
is connected to and controlled by the host device
10
to generate an alarm output in the event that unauthorized operation of the vehicle
2
was detected in accordance with the voltage signals from the detector circuit cluster
11
. In general, the alarm output may be a visual output or an audible output. Since the vehicle
2
is equipped with a horn
26
, exterior lighting
27
and interior lighting
28
, the alarm circuit cluster
12
includes actuators connected to and enabled by the host device
10
to activate the horn
26
, the exterior lighting
27
and interior lighting
28
. Therefore, when the host device
10
detects unauthorized operation of the vehicle
2
in accordance with the voltage signals from the detector circuits
111
-
115
, it will enable the alarm circuit cluster
12
so as to activate the horn
26
, the exterior lighting
27
and the interior lighting
28
, thereby deterring theft.
However, when mounting the conventional vehicle security system
1
on the vehicle
2
, the detector circuits
111
-
115
and the alarm circuit cluster
12
require dedicated connecting lines for connection to the host device
10
. In other words, a large amount of connecting lines are required to mount the conventional vehicle security system
1
on the vehicle
2
. The mounting process is tedious, and the layout of the dedicated connecting lines is complicated. Furthermore, in the case that the vehicle security system
1
is not an original component of the vehicle
2
, the mounting process will require rewiring of the vehicle circuitry, thereby further increasing the difficulty in mounting the conventional vehicle security system
1
.
It is noted that the difficulty in mounting the conventional vehicle security system
1
will be greatly reduced if the existing vehicle circuitry can be used for signal transmission among the host device
10
, the detector circuit cluster
11
and the alarm circuit cluster
12
. Most components of the vehicle
2
require electric power for operation and are thus connected to the battery
29
via a respective power supply line. However, these power supply lines are used solely for dc power distribution. Even if the existing power supply lines are used to connect the host device
10
to the detector circuit cluster
11
in the conventional vehicle security system
1
, the host device
10
will be unable to distinguish the voltage signals from the detector circuits
111
-
115
such that the host device
10
will be unable to detect unauthorized operation of the vehicle
2
.
SUMMARY OF THE INVENTION
Therefore, the object of the present invention is to provide a vehicle security system that uses alternating current signal transmission through a power supply line to simplify the vehicle circuitry and to facilitate the mounting process.
Accordingly, the vehicle security system of this invention is adapted for use in a vehicle having a power supply and a power supply line connected to the power supply. The vehicle security system comprises a detector circuit cluster, an alarm circuit cluster and a host device.
The detector circuit cluster includes a plurality of detector circuits adapted to detect a current state of a respective component of the vehicle and adapted to be connected to the power supply line. Each of the detector circuits is capable of receiving a status request signal unique thereto via the power supply line, and transmitting a status response signal unique thereto and corresponding to the detected state of the respective component via the power supply line in response to the status request signal.
The alarm circuit cluster is adapted to be connected to the power supply line and is capable of receiving an alarm enable signal distinct from the status request and status response signals via the power supply line. The alarm circuit cluster is enabled so as to generate an alarm output upon receipt of the alarm enable signal.
The host device is adapted to be connected to the power supply line, and is capable of transmitting the status request signals for the detector circuits in sequence via the power supply line, receiving the status response signals from the detector circuits via the power supply line, and selectively transmitting the alarm enable signal to the alarm circuit cluster via the power supply line in accordance with the status response signals from the detector circuits.
Each of the status request signals, the status response signals and the alarm enable signal is in the form of an alternating current signal.
Because the status request signals, the status response signals and the alarm enable signal are alternating current signals that are distinct from the power signal normally distributed through the power supply line, signal transmission among the detector circuit cluster, the alarm circuit cluster and the host device can be carried out via the power supply line to simplify the vehicle circuitry and to facilitate installation of the vehicle security system of this invention.


REFERENCES:
patent: 3925763 (1975-12-01), Wadhwani et al.
patent: 4463341 (1984-07-01), Iwasaki
patent: 5128650 (1992-07-01), Peters et al.
patent: 5307048 (1994-04-01), Sonders
patent: 5644172 (1997-07-01), Hodges
patent: 5745027 (1998-04-01), Malville
patent: 6249216 (2001-06-01), Flick
patent: 6310408 (2001-10-01), Hermann
patent: 6326704 (2001-12-01), Breed et al.

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