Patent Publication Number: US-5629667-A

Title: Direction indicator circuit

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to alarm and sensor systems. More particularly, the present invention relates to a electrical circuit for use with doorways and gates which provides direction information to an alarm or announcer. 
     2. Description of the Prior Art 
     A variety of security devices have been employed at doorways and other ports which sound an alarm when activated by presence of an individual. An example of such an alarm is a sensor pad disposed under a door mat, the sensor in electrical communication with an announcer. The announcer is often in the form of a bell, horn, light, or other indicating signal. Another example of an alarm are infrared emitters and receivers spaced on either side of the port. When the IR signal is interrupted by an individual located between the emitter and the receiver, a signal is generated which activates an announcer. Although these and other prior art alarm measures are effective in sensing movement of an individual through a port, they do not indicate whether the individual is coming or going. 
     Oftentimes, the store owner, security guard, or other &#34;employee&#34; is alone at the workplace. In a situation where the employee enters a backroom for example, the activation of an announcer does not inform the employee whether a customer had just left, or a new customer(s) has just arrived. Unable to ascertain the presence of individuals from the announcer alone, the employee is subject to deception by a criminal. It would be highly desirable, therefore, to have an alarm system incorporating circuitry which can detect and announce the direction in which an individual is moving about the port or doorway. 
     Numerous innovations for alarm systems and circuitry have been provided in the prior an that are adapted to be used. Even though these innovations may be suitable for the specific individual purposes to which they address, they would not be suitable for the purposes of the present invention as heretofore described. 
     SUMMARY OF THE INVENTION 
     The present invention relates to an electrical circuit for use in an alarm system. The circuit and alarm system being in electrical communication with an electrical power source. The alarm system has a detector configured to generate a first signal in response to triggering by an individual or other body. The alarm system further has an announcer adapted to produce an IN announcement in response to an IN signal and an OUT announcement in response to an OUT signal. The circuit comprises a first circuit portion which is responsive to the first signal for generating the IN signal to activate the announcer; and a second circuit portion that is responsive to the second signal for generating the OUT signal to activate the announcer. 
     Accordingly, it is an object of the present invention to provide a circuit for use in an alarm system that can provide directional information to an announcer. 
     The novel features which are considered characteristic for the invention are set forth in the appended claims. The invention itself, however, both as to its construction and its method of operation, together with additional objects and advantages thereof, will be best understood from the following description of the specific embodiments when read and understood in connection with the accompanying drawings. 
     BRIEF LIST OF REFERENCE NUMERALS UTILIZED IN THE DRAWING 
     10--circuit 
     VDC--electrical power source 
     SIG A--first signal 
     SIG B--second signal 
     CR 1--first protection diode 
     CR 2--second protection diode 
     R1--first relay 
     R2--second relay 
     R3--third relay 
     R4--fourth relay 
     R1a--contact 
     R1b--contact 
     R2a--contact 
     R2b--contact 
     SW1a--first manual reset switch 
     SW2a--second manual reset switch 
    
    
     BRIEF DESCRIPTION OF THE PREFERRED EMBODIMENT 
     FIG. 1 is a plan view of a circuit constructed in accordance with the present invention; 
     FIG. 2 is a schematic diagram of the circuit of FIG. 1 incorporated into an alarm system; and 
     FIG. 3 is a schematic diagram of the circuit of FIG. 1 incorporated into an alarm system having infrared photo detectors. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     Firstly, referring to FIG. 1 in conjunction with FIG. 2, circuit 10 is illustrated. Circuit 10 receives electrical power from electrical power source VDC and is adapted to respond to inputs from remote signal sources, the inputs being in the form of a first signal SIG A and a second signal SIG B. The first and second signals, SIG A and SIG B, are dc voltages that are on for a period of time sufficient to energize relays R1, R2, R3 and R4. For simplicity of circuitry, the relays may all be of the same voltage and current carrying capacity on relay contacts R1a, R1b, R2a and R2b. 
     Referring to FIG. 1, the operation and sequence of the circuit 10 will now be described. When the first signal SIG A is received first by the circuit 10, the first relay R1 is turned on closing contact R1a and opening contact R1b. A·B&#39;, hereinafter called IN, turns on the third relay R3 latching or holding the first relay R1 on. The opening of contact R1b prevents second signal SIG B from energizing the second relay R2 and further prevents the signal A&#39;·B, hereinafter OUT, from occurring. The signal IN can now be used to activate an announcer, for example as seen in FIG. 2, to light up a lamp or sound a buzzer. 
     When the second signal SIG B is received first by the circuit 10, the second relay R2 is turned on, contact R2a is closed and contact R2b is opened. The OUT signal turns on the fourth relay R4 latching or holding the second relay R2 on. The opening of contact R2b prevents the first signal SIG A from energizing the first relay R1 and further prevents the signal IN from occurring. The OUT signal can now be used to announce, or again as shown in FIG. 2, light up a suitable on/off device such as a lamp or buzzer. 
     SW1a and SW2a are manual reset switches for the IN and OUT signals, respectively, which can be local at the alarm device or remote. It is contemplated that the reset switches be in the form of timed switches which automatically reset the circuit to a default or start up setting after a selected period of no manual attention to the alarm. 
     CR1 and CR2 are protection diodes which prevent the electrical power supply VDC from feeding back to the first and second signal sources after the third and fourth relays R3 and R4 close. 
     Referring to FIG. 3, a schematic view of an exemplary alarm system is shown which incorporates circuit 10. In this alarm system the detector assembly includes infrared photorelays and an infrared beam deflector. A break in one infrared beam may generate a first signal while a break in the other infrared beam may generate a second signal. The first and second signals to be received by the circuit 10 which in turn produces an IN or an OUT signal to the announcer for appropriate announcement. 
     It will be understood that the circuit described above, or two or more together, may also find useful application in other types of alarm or sensor systems differing from the examples described above. 
     While the invention has been illustrated and described as embodied in a circuit for an alarm system, it is not intended to be limited to the details shown, since it will be understood that various omissions, modifications, substitutions and changes in the forms and details of the device illustrated and in its operation can be made by those skilled in the art without departing in any way from the spirit of the present invention. 
     Without further analysis, the foregoing will so fully reveal the gist of the present invention that others can, by applying current knowledge, readily adapt it for various applications without omitting features that, from the standpoint of prior art, fairly constitute essential characteristics of the generic or specific aspects of this invention. 
     What is claimed as new and desired to be protected by Letters Patent is set forth in the appended claims.