Computer anti-theft system

A computer anti-theft system that includes a remote transmitter unit carried by the user, a dongle that physically attaches and selectively locks onto the parallel port on an existing computer, and a software program that is loaded into the computer's memory. When the system is activated, the remote transmitter unit transmits a pulse code signal which is received by a receiver component located inside the dongle. When the pulse code signal is received, the dongle is elevated to an active state. The dongle then transmits a return pulse code signal to the remote transmitter unit and the loop continues. If no pulse code signal is received, the dongle, is elevated to an alarm state. An alarm pulse code signal is then broadcast to the remote transmitter unit and elevating it to an alarm state. In one embodiment, the software program is used to control a solenoid inside the dongle which prevents removal of the dongle from the parallel port. The dongle and remote transmitter are electrically self contained thereby enabling the computer to be turned-off.

BACKGROUND OF THE INVENTION 
1. Field of the Invention 
This invention relates to anti-theft systems for portable objects, and, 
more particularly, to such systems adapted specifically for personal 
computers. 
2. Description of the Related Art 
It is widely known that theft of laptop and desktop personal computers is a 
serious problem and is increasing annually. 
Security devices for computers, such as cables and locks which physically 
attach a computer to a work station are common. So are computer software 
programs which require the user to enter a pre-programmed password into 
the computer before it may be used. It is also common to attach a device 
to a component, such as a floppy disk drive, which renders the computer 
inoperable until removed with the correct key or code (see U.S. Pat. Nos. 
5,400,622 and 5,660,065). 
Motion detecting security systems or devices for small personal items, such 
as suitcases, attache cases, and skis are also widely known (see U.S. Pat. 
Nos. 4,155,079, 4,272,763, and 5,660,065). 
Recently, an integrated alarm system for portable computers has been 
developed which, when armed, sounds an alarm or disables the computer upon 
unauthorized movement of the computer from a stationary position. The 
alarm system includes one or more motion sensors and/or micro switches 
that provide a signal indicating that the portable computer has been moved 
from a stationary position or that the computer is being opened from its 
closed position (see U.S. Pat. No. 5,760,690). 
Also, a security system specifically designed for laptop computers has been 
recently developed which includes a security device internally connected 
to the computer. The security system also includes a remote unit which, 
together with the security device, acts as a vicinity switch which signals 
an alarm when the security device and remote unit are no longer within a 
specific range. In one embodiment, the system includes a motion detecting 
alarm internally connected to the computer,(see U.S. Pat. No. 5,757,271). 
A major drawback with motion detecting alarm systems is that they can only 
be used when the computer is stationary. When the computer is being 
transported, which is the most common situation when theft occurs, the 
motion detecting alarm must be inactive. Another drawback with motion 
detecting alarm systems is that depending upon the sensitivity of the 
motion detecting switches, the computer may be gently moved by a thief 
without activating the motion detecting alarm system. 
A major drawback with internally connected vicinity switch systems is that 
they require one of the bays or slots inside the laptop computer. Further, 
they require the computer's system be turned on when armed, which makes 
them dependent on the laptop's battery. 
Ideally, a security system for a laptop computer should prevent theft while 
the computer is both stationary and while being transported. Further, it 
should be selectively affixed externally to the computer and not require 
the use of a bay or slot inside the computer. Still further, it should not 
be dependent on the computer's system being activated or the computer's 
battery. 
SUMMARY OF THE INVENTION 
It is an object of the invention to provide an anti-theft system for a 
laptop computer to protect it while stationary or when transported. 
It is another object of the invention to provide an anti-theft system that 
is selectively affixed externally to the computer and can only be removed 
and activated or deactivated by the user. 
It is further object of the invention to provide such an anti-theft system 
which is not dependent on the computer's system or battery. 
It is still further object of the invention to provide such an anti-theft 
system that provides an alarm signal to the user away from the computer. 
These and other objects are met by a computer anti-theft system, including 
a remote transmitter unit carried by the user, a fixed receiver unit that 
connects to an external port on a computer, and a software program loaded 
into the computer's memory. The fixed receiver unit is coupled with a 
switching means which, upon activation, automatically activates a first 
alarm means also coupled to the fixed receiver unit. In one embodiment, 
the switching means is a vicinity switch comprised of components located 
in the remote transmitter unit and the fixed receiver unit. During 
operation, both the remote transmitter unit and the fixed receiver unit 
are initially in a low power, hibernating state. When the main button on 
the remote transmitter unit is pressed, a programmed pulse code signal is 
broadcast to the fixed receiver unit. When the pulse code signal is 
received by the fixed receiver unit, the fixed receiver unit is elevated 
to an active state. When the fixed receiver unit is in the active state, a 
pulsed code signal is broadcast to the remote transmitter unit. When the 
pulse code signal is received by the remote transmitter unit, the remote 
transmitter unit is then elevated to an active state. If a pulse code 
signal is not received by the fixed receiver unit while in an active 
state, it automatically elevates to an alarm state. An alarm pulse code 
signal is then broadcast from the fixed receiver unit elevating the remote 
transmitter unit to an alarm state. A second alarm means coupled to the 
remote transmitter unit is then activated to inform the user that the 
fixed receiver unit is fully activated and that a theft may be occurring. 
In other embodiments, the switching means may be a motion detecting switch 
located inside the fixed receiver unit which informs the user that the 
computer has been moved. 
The fixed receiver unit, hereinafter known as a dongle, is designed to 
physically connect and lock onto one of the external ports on the 
computer. Unlike internal bays and slots in which various hardware 
components may be attached but not locked in place, hardware devices are 
not normally attached to external ports when the computer is being 
transported or setup in a temporary location. In the embodiment shown 
herein, the dongle is attached to a parallel port on the computer. 
The software program loaded into the computer's memory is used to program 
the pulse code signal in the remote transmitter unit and the fixed 
receiver unit. It is also used to activate a locking means located inside 
the dongle, thus preventing the dongle's physical removal from the 
parallel port and, to deactivate the fixed receiver unit. 
Both the dongle and remote transmitter unit are independently energized and 
not dependent on the software program or computer power system during use.

DESCRIPTION OF THE PREFERRED EMBODIMENT(S) 
Referring to the accompanying FIGS. 1-5, there is depicted a computer 
anti-theft system, generally referred to as 20, used as a security device 
for a laptop computer 10. The computer 10 includes a main body 12 with a 
rear panel 14 that holds a power plug 16 and a plurality of external 
peripheral device port connectors 17-19. 
The system 20 includes a software program 22, a remote transmitter unit 25, 
and a fixed receiver unit known as a dongle 40. During use, the software 
program 22 is loaded into the computer's memory, the remote transmitter 
unit 25 is carried by the user, and the dongle 40 is selectively locked 
onto the computer's parallel port 19 as discussed further below. 
In the preferred embodiment, a vicinity switch 24 is disposed between the 
remote transmitter unit 25 and the dongle 40 which is automatically 
activated when the remote transmitter 25 and dongle 40 are beyond a 
specific distance from each other. 
As shown in FIG. 2, the remote transmitter unit 25 includes a circuit card 
26 with a transmitter component 27, an LED 29, a speaker 31, a battery 32, 
an optional on/off switch 33, and a main push button switch 35 all 
electrically connected together. During use, the transmitter component 27 
broadcasts a continuous pulse code signal 37 capable of being received by 
a receiver component 66 located inside the dongle 40 as shown in FIG. 3. 
When the pulse code signal 37 is received by the receiver component 66, a 
circuit board 65 located inside the dongle 40 is elevated to an active 
state. When the pulse code signal 37 is not received by the receiver 
component 66, the control card 65 becomes elevated to an alarm state, 
which in turn, activates the audio and/or visual alarms 85, 88, 
respectively, electrically connected thereto. An alarm pulse code signal 
38 is then transmitted to the transmitter component 27 which elevates it 
into an alarm state. A speaker 31 and LED 29 coupled to the circuit card 
26 are then activated to inform the user that a theft may be occurring. 
Also as shown in FIG. 3, the dongle 40 is designed to attach to the 
parallel port 19 on the rear panel 14 of the computer 10 via a D-25 pin 
connector 44. A locking means is included in the dongle 40 which 
physically locks the dongle 40 to the parallel port 19. The dongle 40 
includes an outer housing 42 with an internal cavity 46 formed therein. 
Disposed inside the internal cavity 46 is the circuit card 65 with an 
integrally connected receiver component 66. A solenoid 70, a battery 80, a 
speaker 85 and optional LED 88 are electrically connected to the circuit 
card 65. Extending perpendicularly from the opposite sides of the rear 
surface of the outer housing 42, are adjustment screws 50. At least one 
adjustment screw 50 includes a proximal neck 52 and distal shank 56. A 
blade element 58 is formed on the tip of each distal shaft 56. Disposed 
around the upper portion of the distal shaft 56 and inside the outer 
housing 42 is a longitudinally aligned spring 54 designed to hold the 
adjustment screw 50 in an extended position on the outer housing 42. 
Located inside the outer housing 42 and spaced apart and longitudinally 
aligned with each adjustment screw 50 is an extension 60. The extension 60 
includes an upper head 62 with a slot 63 formed therein designed to engage 
the blade element 58 on the distal shaft 56 when the adjustment screw 50 
is pressed inward. External threads 64 are formed on the distal portion of 
the extension 60 which connect to standard threaded bores 15 located on 
the rear panel 14 on opposite sides of the parallel port 19. 
The locking means includes a transversely aligned solenoid 70 with an arm 
72 that extends longitudinally therefrom when activated. The solenoid 70 
is disposed adjacent to the space created between the distal shank 56 on 
the adjustment screw 50 and the upper head 62 on the extension 60. When 
the solenoid 70 is activated, the arm 72 extends outward and prevents the 
blade element 58 from engaging the slot 63 on the extension 60, thus 
preventing engagement of the distal shank 56 to the extension 60. After 
the extension 60 is attached to the bore 15, the arm 72 prevents the 
extension 60 from being disconnected therefrom. It should be understood 
that the locking means described above could be replaced with a physical 
lock and key that attaches the dongle 40 to the parallel port 19. 
The software program 22 is designed to activate and deactivate the system 
20 and to adjust the position of the arm 72 inside the dongle 40. When the 
software program 22 is installed on the computer, it instructs the user on 
how to setup both the remote transmitter unit 25 and the dongle 40. A 
password and code is then selected and entered into the computer, and 
stored in the receiver component 66 and transmitter component 27 via the 
parallel port 19. After the transmitter component 27 and receiver 
component 66 are programmed, the remote transmitter unit 25 and dongle 40 
may communicate with each other. The software program 22 is then used to 
move the arm 72 on the solenoid 70 from the unlocked to the locked 
position. The original password may be also used to prevent operation of 
the software program and to change the pulse code signal or to unlock the 
dongle 40. 
After the remote transmitter unit 25 and dongle 40 are initially 
programmed, they are automatically activated in a hibernated state. 
Optional main switch 33 may be included on remote transmitter unit 25 to 
selectively activate and deactivate the remote transmitter unit 25. As 
shown in FIG. 5, once the system 20 is activated, the transmitter 
component 27 sends the pulse code signal 37 to the receiver component 66 
located in the dongle 40. If the pulse code signal 37 is not received, the 
receiver component 66 is activated in an alarm state and an alarm pulse 
code signal 38 is broadcast to the remote transmitter unit 25. If at any 
time, the receiver component 66 receives pulse signal code 37, the loop 
continues and the circuit cards 26 and 65 remain in an active state. 
In another embodiment shown in FIGS. 3 and 4, the dongle 40 may include a 
motion detecting switch 90 which acts as an additional component to the 
vicinity switch or may replace the vicinity switch. The motion detecting 
switch 90 may comprise a mercury switch attached to the outer housing 42 
which is electrically coupled to the circuit card 65. When the dongle 40 
is moved, the motion detecting switch 90 is activated which elevates the 
circuit card 65 to an alarm state and activates the speaker 85 and LED 88. 
In compliance with the statute, the invention, described herein, has been 
described in language more or less specific as to structural features. It 
should be understood, however, the invention is not limited to the 
specific features shown, since the means and construction shown comprised 
only the preferred embodiments for putting the invention into effect. The 
invention is, therefore, claimed in any of its forms or modifications 
within the legitimate and valid scope of the amended claims, appropriately 
interpreted in accordance with the doctrine of equivalents.