Low power credential detection device for access control system

Patent metadata

Field	Value
Publication number	US-9978194-B2
Application number	US-201615275941-A
Country	US
Kind code	B2
Filing date	Sep 26, 2016
Priority date	Dec 22, 2015
Publication date	May 22, 2018
Grant date	May 22, 2018

Abstract

An access control device including a credential reader circuit configured to enter a standby mode, awaken from a standby mode, and receive data from a nearby credential. The access control device further includes a credential detection circuit having a memory configured to store program instructions, an antenna, and a processor electrically coupled to the antenna and to the credential reader circuit, wherein the processor is configured to execute the stored program instructions to: transmit an interrogation signal, receive a reflected interrogation signal with the antenna, transmit an activation signal to the credential reader circuit in response to the received reflected interrogation signal wherein the reflected interrogation signal includes I and Q values, receive a false detection signal from the credential reader circuit, and adjust at least one of the I and Q threshold values of the reflected interrogation signal.

First claim

What is claimed is:

1. An access control device, comprising:
a credential reader circuit structured to enter a standby mode, awaken from a standby mode, and receive data from a nearby credential; and
a credential detection circuit, including:
a memory configured to store program instructions;
an antenna; and
a processor electrically coupled to the antenna and to the credential reader circuit, the processor configured to execute the stored program instructions to:
transmit an interrogation signal;
receive a reflected interrogation signal with the antenna; and
transmit an activation signal to the credential reader circuit in response to the received reflected interrogation signal;

wherein the reflected interrogation signal has I and Q values, and the processor is further configured to execute stored program instructions to:
receive a false detection signal from the credential reader circuit; and
adjust at least one of the I and Q values of the reflected interrogation signal; and

wherein the I and Q values of the interrogation signal include initial values of in phase and quadrature phase measurements determined as a function of an expected measurement value and an acceptable range of signal noise.

2. The device of claim 1 , wherein the processor is further configured to execute stored program instructions to reduce the value of at least one of the I and Q values in response to transmitting the activation signal without receiving the false detection signal.

3. The device of claim 1 , wherein the processor is further configured to execute stored program instructions to increase the exceeded values of at least one of the I and Q values in response to receiving a plurality of false detection signals.

4. The device of claim 1 , wherein the I and Q values of the reflected interrogation signal are one of voltage amplitude, current amplitude, and an impedance.

5. The device of claim 1 , wherein fluctuations in environmental conditions generate the signal noise.

6. The device of claim 1 , wherein the antenna is printed on a circuit board.

7. The device of claim 1 , wherein to adjust at least one of the I and Q values of the reflected interrogation signal comprises to adjust the I value independently of the Q value.

8. An access control device, comprising:
a credential reader circuit structured to enter a standby mode, awaken from a standby mode, and receive data from a nearby credential; and
a credential detection circuit, including:
a memory configured to store program instructions;
an antenna; and
a processor electrically coupled to the antenna and to the credential reader circuit, the processor configured to execute the stored program instructions to:
transmit an interrogation signal;
receive a reflected interrogation signal with the antenna; and
transmit an activation signal to the credential reader circuit in response to the received reflected interrogation signal;

wherein the reflected interrogation signal has I and Q values, and the processor is further configured to execute stored program instructions to:
receive a false detection signal from the credential reader circuit; and
adjust at least one of the I and Q values of the reflected interrogation signal;

wherein the credential comprises a passive tag, and
wherein the credential is one of a low frequency proximity credential and a contactless smart credential.

9. The device of claim 8 , wherein the processor is further configured to execute stored program instructions to reduce the value of at least one of the I and Q values in response to transmitting the activation signal without receiving the false detection signal.

10. The device of claim 8 , wherein the processor is further configured to execute stored program instructions to increase the exceeded values of at least one of the I and Q values in response to receiving a plurality of false detection signals.

11. A method of calibrating a wakeup device, comprising:
setting an I threshold value and a Q threshold value;
energizing an antenna to transmit an interrogation signal;
receiving a reflected interrogation signal;
transmitting an activation signal to a credential reader circuit in response to the reflected interrogation signal, wherein the reflected interrogation signal includes I and Q signal values;
receiving, from the credential reader circuit, a false detection signal indicative of a failure of the credential reader circuit to detect a credential; and
adjusting only one of the I threshold value and the Q threshold values as a function of at least one of the I signal value and the Q signal value.

12. A method of calibrating a wakeup device, comprising:
setting an I threshold value and a Q threshold value;
energizing an antenna to transmit an interrogation signal;
receiving a reflected interrogation signal;
transmitting an activation signal to a credential reader circuit in response to the reflected interrogation signal, wherein the reflected interrogation signal includes I and Q signal values;
receiving a false detection signal;
adjusting at least one of the I threshold value and the Q threshold values as a function of the I signal value and the Q signal value; and
deriving a digital value of an observed antenna in phase measurement and a digital value of an observed antenna quadrature phase measurement from an analog value using an analog to digital converter.

13. The method of claim 12 , wherein the step of setting includes setting the I threshold value and the Q threshold value at the point of installation of the wakeup device.

14. The method of claim 12 , further comprising decreasing the range of at least one of the in phase measurement and the quadrature phase measurement in response to transmitting an activation signal without receiving a false detection signal.

15. The method of claim 12 , further comprising repeating the steps of the method for calibrating the wakeup device at regular intervals.

16. The method of claim 12 , wherein the step of adjusting includes adjusting the I threshold value independently of the Q threshold value.

17. The method of claim 16 , wherein the step of adjusting includes adjusting at least one of the I threshold value and the Q threshold values as a function of the I signal value and the Q signal value after a predetermined number of false detection signals has been received.

18. A method of calibrating a wakeup device, comprising:
setting an I threshold value and a Q threshold value;
energizing an antenna to transmit an interrogation signal;
receiving a reflected interrogation signal;
transmitting an activation signal to a credential reader circuit in response to the reflected interrogation signal, wherein the reflected interrogation signal includes I and Q signal values;
receiving a false detection signal;
adjusting at least one of the I threshold value and the Q threshold values as a function of the I signal value and the Q signal value; and
wherein the step of receiving a false detection signal includes receiving a false detection signal as a result of one of the I value being different than the I threshold value and the Q value being different than Q threshold value.

19. The method of claim 18 , further comprising:
determining which one of the I signal value and Q signal value causes the false detection signal; and
wherein the step of adjusting includes adjusting one of the I threshold and the Q threshold which corresponds to the one of the I signal value and the Q signal value that causes the false detection signal.

Assignees

• Schlage Lock Co Llc

Inventors

• Newby David I
• Nardelli Frank A
• Ainley William B
• Reuter Michael
• Smith David
• Kunnoth Jineesh

Classifications

• G07C9/00309 Primary

  operated with bidirectional data transmission between data carrier and locks · CPC title

• G07C9/28 Primary

  the pass enabling tracking or indicating presence · CPC title

• G06K19/0723

  the record carrier comprising an arrangement for non-contact communication, e.g. wireless communication circuits on transponder cards, non-contact smart cards or RFIDs · CPC title

• G06K7/00

  Methods or arrangements for sensing record carriers, {e.g. for reading patterns} (methods or arrangements for marking the record carrier in digital fashion G06K1/00; pattern recognition G06F18/00; arrangements for image or video recognition or understanding G06V10/00; character recognition, recognising digital ink or document-oriented image-based pattern recognition G06V30/00) · CPC title

• G07C9/00111 Primary

  Physics · mapped topic