Systems and methods for security sensing in a power cable for an article of merchandise
Embodiments of the present invention are directed to merchandise security systems and methods for displaying and protecting an article of merchandise from theft. In one example, the system includes a sensor configured to be secured to the article of merchandise, wherein the sensor includes alarming circuitry. The system also includes a tether comprising a pair of conductors electrically connected to the alarming circuitry, wherein the pair of conductors is configured to transfer power to the sensor and/or to the article of merchandise. In response to power ceasing to be transferred, the alarming circuitry is configured to monitor an electrical signal transmitted through the pair of conductors in order to determine whether the tether has been cut or removed from the sensor.
1. A merchandise security system for displaying and protecting an article of merchandise comprising:
a sensor configured to attach to the article of merchandise, the sensor comprising alarming circuitry and a power source; and
a tether comprising a pair of conductors electrically connected to the alarming circuitry,
wherein at least one of the pair of conductors is configured to transfer power from an input power source to the sensor and/or to the article of merchandise, and
wherein, in response to power transfer from the input power source ceasing, the alarming circuitry is configured to initiate a security scan using the power source of the sensor that comprises monitoring an electrical signal on the pair of conductors in order to determine whether the tether has been cut or removed from the sensor.
2. The merchandise display system of claim 1 , wherein the pair of conductors comprises a positive power conductor and a ground conductor.
3. The merchandise display system of claim 1 , wherein the tether is coupled to a recoiler such that the tether is extendable and retractable relative to the recoiler.
4. The merchandise display security device of claim 3 , wherein each of the sensor and the recoiler comprises at least one resistor electrically connected to the pair of conductors in a sense loop circuit, and wherein the alarming circuitry is configured to determine a change in resistance in the sense loop circuit.
5. The merchandise display system of claim 4 , wherein the alarming circuitry and the pair of conductors define the sense loop circuit, and wherein the resistor in the recoiler is disposed across the pair of conductors.
6. The merchandise display system of claim 3 , wherein an end of the tether comprises a connector configured to releasably engage the sensor.
7. The merchandise display system of claim 1 , wherein the alarming circuitry is configured to generate a visual and/or an audible alarm signal in response to the sensor being removed from the article of merchandise, the tether being removed from the sensor and/or the tether being cut.
8. The merchandise display system of claim 1 , wherein the sensor comprises a transfer port configured to facilitate wireless communication with a key for arming and/or disarming the alarming circuitry.
9. The merchandise display system of claim 1 , further comprising a base for removably supporting the sensor thereon.
10. The merchandise display system of claim 1 , wherein the tether consists of only the pair of conductors.
11. A method for displaying and protecting an article of merchandise comprising:
transferring power from an input power source through a tether to the article of merchandise or to a sensor attached to the article of merchandise, the tether comprising a pair of conductors electrically connected to the sensor; and
initiating a security scan with alarming circuitry powered by a separate power source, in response to power ceasing to be transferred by the input power source, wherein the security scan comprises:
generating an electrical signal on the pair of conductors; and
monitoring the electrical signal to determine whether the tether has been cut or removed from the sensor.
12. The method of claim 11 , wherein monitoring comprises repeatedly determining a voltage level in predetermined increments of time.
13. The method of claim 12 , wherein the determining comprises determining whether the voltage level is greater than a predetermined voltage level.
14. The method of claim 13 , further comprising generating a visual and/or an audible alarm signal when the voltage level is greater than the predetermined voltage level.
15. The method of claim 13 , further comprising repeating the step of determining the voltage level if the voltage level is greater than the predetermined voltage level.
16. The method of claim 12 , wherein the generating comprises generating the electrical signal on the pair of conductors prior to determining the voltage level.
17. The method of claim 11 , wherein monitoring comprises determining a change in total resistance in a sense loop circuit defined at least by the sensor, the pair of conductors, and a plurality of resistors.
18. The method of claim 17 , further comprising determining whether the pair of conductors has been shorted.
19. The method of claim 11 , further comprising determining a voltage level in a sense loop circuit defined at least by the sensor and the pair of conductors.
20. The method of claim 11 , further comprising ceasing power transfer through the tether prior to the step of initiating the security scan.