Motion sensing alarm switch

An anti-theft alarm device for household items is disclosed. The device employs a motion sensor unit subject to magnetic control such that the alarm may be disabled, set to go off or reset after being sounded. The magnetic control is applied by a magnetic probe to a conductive ball sensor normally maintained on a nonconductive area between conducting surfaces of opposite polarity. When magnetic attraction is removed the ball is free to respond to motion and complete an alarm circuit. A mounting casing is provided, which may be used to mount the motion sensing unit and alarm circuit in a compact apparatus. Additional mounting hardware is provided to enable mounting the motion sensing unit on angulated or curved surfaces. The magnetic control functions may be set by radio control.

BACKGROUND OF THE INVENTION 
The subject invention relates to alarms and more particularly to an alarm 
system which senses the motion of an article to which it is attached. 
Particularly, the alarm is adaptable to remote control and is designed to 
be useful with household items such as televisions, stereos, and so forth. 
With the ever increasing frequency of burglaries and housebreakings, the 
need has become apparent to protect the objects of such crimes, typically 
easily transportable and readily marketable household items such as 
television sets and sound system equipment. Up to this point, a simple and 
effectively controllable warning switch for indicating the displacement of 
a number of such household items from their normal position in the event 
of a theft has not been available. Ideally, such warning devices should 
embody a disabling control since the homeowner may desire to move 
household items for cleaning or other purposes without triggering an 
alarm. To be convenient, the capability to set a number of such devices at 
once throughout a home is desirable. Moreover, the devices need to be 
easily mountable in a variety of locations to adapt to various household 
devices. 
To date, motion sensing devices have been provided which detect abnormal 
motion changes or accelerations above a certain level. U.S. Pat. No. 
3,927,286 is an example. Such devices are typically overcomplex for the 
application here envisioned and do not provide the mounting flexibility 
and controlled resetting and arming features necessary in a practical home 
device. Neither have such devices been adapted to remote control so as to 
enable multiple devices to be easily reset by automatic means. 
SUMMARY OF THE INVENTION 
It is therefore an object of the invention to provide an improved alarm 
device. 
It is another object of the invention to provide an inexpensive alarm 
device which may be used in multiple numbers to protect household items 
from theft. 
It is a further object of the invention to provide an alarm which will 
detect the slightest motion but which is yet positively settable and 
resettable by an inexpensive means. 
It is a further object to provide such an alarm device adapted for remote 
control purposes. 
It is yet another object of the invention to provide an alarm device which 
is mountable in the variety of orientations necessary in order to protect 
a variety of household items. 
These and other objects of the invention are achieved by a motion sensor 
unit including a compartment having conductive areas and a nonconductive 
resting area located at one portion of the compartment. A motion sensor 
element attractable by magnetic force and having a conductive surface is 
held normally in a nonconductive position by an adjacent magnetic field 
source. The magnetic field source may be controlled such that magnetic 
force may be selectively applied to the sensor element. When the alarm is 
armed by removing the magnetic field control from the sensor element, any 
movement of the device will result in the sensor element leaving its 
insulated position and contacting conductive areas of the compartment, 
thereby completing an alarm circuit. The alarm circuit then activates an 
appropriate warning device. 
According to another aspect of the invention, a case for the motion sensing 
unit is provided with a complementary compartment for removably mounting 
the motion sensor unit in various orientations. According to yet another 
aspect of the invention the motion sensor unit is provided with mounting 
means designed to allow the motion sensing unit to successfully operate on 
curved and angulated surfaces.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
FIGS. 1 and 2 illustrate the motion sensing unit used in the preferred 
embodiment of the alarm device of the subject invention. This unit 
includes upper and lower conductive plates 11, 13, a conductive ring 15, 
and a conductive ball 17, all of which are mounted within a cubical 
housing 21. While a cubical shape is preferred for the sensing unit, other 
shapes could be used according to the invention. 
The ball 17 is prefarably copper plated steel. The copper ring 15 
surrounding the ball 17 is cylindrical in shape and not entirely closed, 
leaving a gap at one side of the ring 15. That gap is filled by an 
insulating pad 23. 
The thin copper plates 11 and 13 mounted above and below the ring are 
preferably substantially circular and in conformance with the diameter of 
the ring. They are spaced from the ring by the square dimension of the 
housing 21 such that the ball 17 may rest on either surface 11 or 13 
without touching the other surface 13, 11 but such that the ball 17 cannot 
pass through the openings between the plates 11, 13 and the ring 15. The 
ball then is effectively contained within the plates 11, 13 which are 
separated by an insulating air spaced from the ring 15. The plates 11, 13 
and ring 15 effectively encase the ball 17. The second pad 25 is made 
concave to obtain a desired degree of insensitivity to motion when the 
alarm is armed. 
The housing 21 has a hollow neck 27 which provides an opening into the 
housing 21 adjacent the gap in the copper ring occupied by the insulating 
pad 23. The neck may initially be square in cross section forming a nut 
29. The nut 29 may then form integrally into a threaded shaft 31. The nut 
29 and threaded shaft 31 facilitate locking the sensing unit into mounting 
apparatus as hereafter described. The interior of the neck 21 is 
dimensioned to receive a magnetic probe 19, which is preferably square in 
cross section. 
The magnetic probe 19 is designed to control the ball 17 in the sensing 
unit. It includes a nonconductive, nonmagnetic handle 20, and a permanent 
magnet 22 affixed to the handle. As discussed above, the probe 19 is 
dimensioned to slide into and out of the interior of the housing neck 27. 
When the probe 19 is in place in the neck 27, the permanent magnet 22 
rests adjacent the insulator pad 23. 
With the probe 19 in place in the neck 27, the sensing unit is in a 
disarmed state. The permanent magnet 22 attracts the conductive ball 17 
against the insulating pad 23 and maintains the ball 17 in position on the 
concave resting pad 25. In this state, motion will not be detected by the 
sensing unit. 
To arm the alarm, the slideably mounted magnetic probe 19 is removed from 
the device. The ball 17 is then subject to no restraining force and the 
slightest perturbation of the housing 21 by a would-be thief will cause 
the ball to roll freely within the confines of the plates 11, 13 and the 
ring 15 and to thereby come under the influence of a small magnetic 
element 18. When the ball contacts one of the plates 11 or 13 and the ring 
15, it closes a circuit path taken off leads shown schematically as 27, 
29, 31. This circuit closing is then utilized to activate an alarm device. 
When it is desired to deactivate the alarm, the magnet probe 19 is moved 
back into the receptacle, attracting the ball 17 back to the nonconductive 
pads 23, 25 and opening the circuit. It may be noted, that, if desired, 
the ball itself could be connected to a lead and the plates 11, 13 
eliminated. However, this structure is not preferred. 
To insure a positive circuit closing when the ball 17 leaves the resting 
pad 25, the small magnet 18 is provided adjacent the conductive ring 15. 
This magnet 18 is insulated from the positive and negative electrode and 
is selected to have a force field which will not interfere with that 
applied by the control probe 19 when the control probe is in the disarming 
position. 
The particular advantage provided by the cubical sensor element of FIGS. 1 
and 2 is illustrated in FIG. 3 where the sensor element is incorporated in 
an alarm device according to the preferred embodiment of the invention. 
The alarm device of FIG. 3 includes a mounting compartment for the sensor 
unit and an alarm circuit. In the preferred embodiment, the mounting 
compartment 26 is cubical and open at one face to permit insertion of the 
motion sensor cube detailed above. 
The mounting compartment further includes a number of slots 33 and openings 
35, which are wide enough to receive the neck 27 of the probe receptacle 
of the sensor cube. By use of such openings 35 and the slots 33, the alarm 
device case 37 may be attached in horizontal or vertical positions with 
access to various of its sides cut off. By appropriately inserting the 
sensing unit cube and associated probe into the mounting compartment, the 
concave resting pad 25 of the sensing unit is properly oriented in a plane 
substantially perpendicular to the force of gravity. Without such 
positional flexibility, the alarm would be limited to one mounting 
position; otherwise, gravity would cause the ball 17 to fall off the 
concave pad 25. 
To complete the alarm device of FIG. 3, an alarm circuit is provided 
including a warning device 34 connected for activation by a pair of 
batteries 36. The batteries 36 and the warning device 34 are connected in 
a circuit such that when the ball 17 closes a circuit between one of the 
pads 11, 13 and the conducitve ring 15 an energizing signal is applied to 
the warning device 34. The warning device 33 may be a speaker which emits 
a squawking sound, a bell, buzzer, horn, or other device. In a more 
sophisiticated version the warning device 34 could be a radio transmitter 
activated by the circuit closing. 
Several advantages of the just described alarm device structure may be 
noted. First, the device may be mounted in various planes. Second, a 
special tool, the magnetic probe 19, is required to deactivate the device, 
adding to its fool proof nature. Third, the device may be mounted within a 
cabinet and an aperture provided for inserting and removing the magnetic 
control probe. Finally, the alarm device can be mounted remotely from the 
probe-controlled sensing unit. 
As alluded to earlier, the limited space available in many models of 
television sets, stereos, radios, CB radios etc. may necessitate 
separation of the motion sensing unit from the alarm device. In many 
instances, the back panels of such appliances exhibit various angles and 
curved surfaces. To employ the magnetic probe 19 together with a sensing 
unit such as just described in connection with FIG. 1 and FIG. 2, it is 
necessary to mount the cube sensor on such curved and angulated surfaces 
such that the ball resting pad 25 is perpendicular to the gravitational 
force on the ball. The structure illustrated in FIGS. 4 through 7 
accomplishes this task. This structure is designed to provide easy 
installation and adjustment as well as maximum adaptability to various 
surfaces. 
FIG. 4 illustrates a sensing unit frame 41 preferably made of plastic and 
molded in halves to facilitate easy manufacture. The signal unit frame is 
concave in shape and bears first and second shelves 43, 45 which form a 
mounting receptacle 46 for the cubical sensing unit. An aperture 47 is 
provided to permit the threaded neck 31 of the sensor unit to protrude 
through the center of the concave mating surface 51 of the sensing unit 
frame 41. This aperture 47 may be made square to lock with the square 
portion 29 of the sensor unit neck 27. The signal unit frame 41 may be 
made of plastic halves which are cemented together to secure the cubical 
sensor unit within the mounting receptacle 46 of the sensing unit frame 
41. 
The sensing unit frame 41 cooperates with a second piece of mounting 
hardware, a panel mounting bracket 49 illustrated in FIG. 5. This bracket 
49 includes a concave surface 50 complimentary to that of the rear surface 
51 of the sensing unit frame 41. This concave surface 50 bears a long slot 
52 through which the neck 27 of the motion sensing unit may pass. Attached 
to the back of the concave surface 50 of the panel mounting bracket 49 is 
a circular mounting flange 55 having radial indentations 57 therein. 
The last element of the mounting hardware is a lock nut 59 illustrated in 
FIG. 6. This nut 59 has a rounded cap 61 forming integrally into a square 
nut. The nut 59 is designed to thread onto the shaft 31 of the sensing 
unit. 
All mating surfaces of the components FIGS. 4, 5 and 6 are preferably rough 
or serrated to facilitate positive positioning. These surfaces include the 
signal unit frame mating surface 51, the panel mounting bracket mating 
surface 50, and the cap 61 of the lock nut 59. 
FIG. 7 illustrates the use of the mounting hardware to mount a motion 
sensing unit on an angulated panel 63. A hole is drilled in the panel 63 
to accomodate the neck 27 of the sensing unit. A panel mounting bracket 49 
is located on the inner surface 62 of the panel 63, leveled and attached 
by cementing or by double sided adhesive tape. Another panel mounting 
bracket 49 is located on the outside 64 of the panel 63 and similarly 
attached. The two panel mounting brackets 49 are oriented respectively 
such that their slots 52 line up, permitting the threaded shaft 31 of the 
motion sensing unit to pass through both panel mounting brackets 49 and 
the hole drilled in the panel 63. 
The sensing unit frame 41 is then installed through the hole in the panel 
and respective slots 52 of the panel mounting brackets 49. The mating 
surface 51 of the signal unit frame 41 mates with the concave surface 50 
of the panel mounting bracket 49 permitting the surfaces 43, 45 of the 
mounting receptacle 46 to be maintained in a position perpendicular to the 
gravitational force vector. On the outside of the panel 63, the lock nut 
59 is screwed on to the threaded shaft 31. The magnetic probe 19 is 
inserted into the neck 27 to retain the sensing unit in an "off" condition 
while these operations are taking place. The handle 20 of the magnetic 
probe 19 is then positioned to a horizontal level and secured at that 
level by the lock nut 59. 
When it is desired to apply the panel mounting brackets 49 to curved 
surfaces, the circular flange 55 is cut along the indentations 57. This 
cutting provides the flexibility necessary for maximum surface contact 
when the mounting brackets 49 are attached. 
FIGS. 8 and 9 illustrate an alternative motion sensing unit and associated 
control switch. This embodiment provides a slidable control probe mounted 
in a housing integrally formed with that containing a motion sensing unit, 
which may be constructed identically to that just described above. This 
sensing unit 111 is generally illustrated in FIG. 8 and will not be 
further detailed, other than to note the addition of an optional threaded 
adjustment plunger 113 to vary the amount of force necessary to jar the 
conductive ball from its resting platform. 
To provide control of the ball 17 in the embodiment of FIG. 8, a slideable 
switch 119 is provided. This switch includes a nonconductive, nonmagnetic 
portion 120 and a permanent magnet element 122, which may be an Alnico 
magnet. 
To arm the alarm, the slideably mounted magnetic switch 119 is moved to the 
"on" position. When it is desired to deactivate the alarm, the magnet 
switch 119 is moved back to the "off" position, attracting the ball 17 
back to the nonconductive pads 23, 25. This sensor unit of FIGS. 8 and 9 
may be used in connection with an alarm device as illustrated in FIG. 3. 
Since, in practice, it may prove most effective to use multiple alarm 
devices configured according to the preferred embodiment in a single home, 
an embodiment particularly suited to such application is illustrated in 
FIG. 10. Since the alarm can be armed or reset by the simple sliding of 
the magnetic probe 19 or the magnetic actuating element 119, it is 
possible to accomplish arming and disarming with an actuator 77, which may 
be a well-known actuator such as a solenoid. The actuator 77 is then is 
turn activated by an output signal from a simple radio receiver 79 upon 
receiving a signal from a transmitter 71. Such transmitters and receivers 
are well-known elements of such systems as garage door closers. Thus, a 
homeowner merely has to press the "on" button on his transmitter to arm 
multiple warning devices throughout his home before leaving or retiring 
for the evening. Since the device of the preferred embodiment of the 
invention may be constructed of a dimension on the order of a cigarette 
package, it could be easily mounted in the interior of various household 
items, out of sight of a would-be thief and conveniently armed from 
without by means of the transmitter 71. 
As may be apparent, many modifications may be made in the just disclosed 
preferred embodiment of the invention without departing from the spirit 
and scope thereof. Therefore, it is to be understood that, within the 
scope of the appended claims, the invention may be practiced other than as 
specifically described above.