GB2420051A

GB2420051A - Radio Proximity Sensor

Info

Publication number: GB2420051A
Application number: GB0424358A
Authority: GB
Inventors: Richard Hoptroff
Original assignee: Individual
Current assignee: Individual
Priority date: 2004-11-04
Filing date: 2004-11-04
Publication date: 2006-05-10
Also published as: GB0424358D0

Abstract

This invention relates to devices for proximity detection and tracking of people (and other objects) as they move around. It is a detector which reads the unique ID codes of radio communication devices such as Bluetooth, WiFi and cellphone radios within range and conveys these codes, or some other codes derived from them, to a computing device.

Description

Radio Proximity Sensor This invention relates to devices for proximity

detection and tracking of people (and other objects) as they move around. In applications such as access control and employee clocking in/out, a common solution is for the person to carry a key' such as a radiofrequency transmitter or magnetic swipe designed to identify them. The key is identified when its identification code is read by a detector. The detector then typically transmits the key's identification code to a central computer. The computer would then complete the required task, such as providing access or logging an employee's presence on a timesheet.

Such proximity detection and tracking systems have the disadvantage that they require a custom-made key to be carried by the person. Additionally, some action is usually required to effect the proximity detection, e.g. bringing the key within a few centimeters of the detector, or swiping the magnetic strip through a card reader. Also, the key might be lost or one might forget to carry it.

An object of this invention is to provide a system which allows an existing radio communications device to provide proximity detection and tracking in addition to its intended use for radio communications. The invention requires that the radio is relatively short range and that it contains a unique identification code intended for the purposes of establishing and maintaining a communications link. The vast majority of such devices in common use operate in the FCC unlicensed 5GHz National Information Infrastructure (U- NIl) frequency band or in the FCC unlicensed 2.4GHz Industrial, Scientific, Medical (ISM) band and so it is to such devices that the present invention is directed. Examples include Bluetooth, ZigBee and WiFi radios.

A detector could imitate a corresponding communications device attempting to establish a communications link and, in so doing, enquire the unique ID code of the proximate radio; this unique ID code could then be used for the purposes of proximity detection and tracking rather than the intended purpose of establishing a communications link; the detector could terminate communication once the ID code was obtained and would not need to further establish the communications link. Such a device would have two main advantages. First, it uses an existing device that the person carries (e.g. a mobile phone) rather than burdening them with an additional device. Second, it requires no action on behalf of the user to activate it; the presence of the radio alone is sufficient to provide proximity detection and tracking.

According to a first aspect of the invention, a device cothpriscs a microprocessor and radio that detects the presence of wireless network communications devices operating in the FCC 5GHz (U-NIl) band or FCC Radio Proximity Sensor Page 2 2.4GHz (ISM) frequency bands by imitating a corresponding communications device searching for a communications partner so that the proximate communication devices offer their unique ID codes and where these unique ID codes are then used as the basis of a proximity detection mechanism.

According to a second aspect of the invention, a method of proximity detection of wireless network communications devices operating in the FCC 5GHz (U-NIl) band or FCC 2.4GHz (ISM) frequency bands the steps of: imitating a corresponding communications device searching for a communications partner so that the proximate communications devices offer their unique ID codes and using these unique ID codes as the basis of a proximity detection.

When the unique ID code of a proximate device has been detected, the conversation is terminated; no attempt is made to establish a communications link. The detected unique ID may be conveyed, either directly or after re- coding in a different format, to a computing device which takes the appropriate action such as providing access or logging the presence of the wireless communication device.

The codes transmitted to the computing device may not be identical to the original ID codes which were detected, but derived from it. For example: * For brevity, the ID code may be compressed or hash-coded.

* For security, the ID code may be encrypted.

* For inter-operability, the ID code may be used to derive a unique or nearly unique ID code in another data format, for example the Wiegand data format used by proximity detecting card readers, thus providing immediate compatibility with these devices.

The whole process would be repeated frequently to provide a continuous proximity sensing and tracking service. If required and if the radio was capable, the process may imitate the search calls of several different communications protocols (e.g. Bluetooth and WiFi) in order to detect a variety of types of device.

A preferred embodiment of the invention will now be described with reference to the accompanying figures in which: FIGURE 1 shows a block diagram of the main components of the proximity detector / tracking device.

Radio Proximity Sensor Page 3 FIGURE 2 shows a flow chart of the functioning of the device.

As shown in figure 1, the proximity detector 1 comprises a microprocessor 2, and communications radio 3 which may communicate with one or more other communications radios 5 whose presence is being detected. Serial data output 4 sends the ID codes of all detected devices 5 in range of detector 1.

Figure 2 shows a flow chart of the functions of the microprocessor 2 relevant to the present invention. The microprocessor loops through a sequence of four functions: - It instructs communications radio 3 to imitate a search call to identify other communications devices 5 within range.

- As other communications devices 5 in range respond with their ID codes, these are conveyed to computer via serial link 4.

- When no further communications devices 5 respond, the search call is terminated.

- The microprocessor may pause for a while to avoid excessive radio frequency channel usage.

Claims

Radio Proximity Sensor Page 4 CLAIMS

1. A device comprising a microprocessor and radio that detects the presence of wireless network communication devices operating in the FCC 5GHz (U-NIl) or FCC 2.4GHz (ISM) frequency bands by imitating a corresponding communications device searching for a communications partner so that the proximate communication devices offer their unique ID codes and where these unique ID codes are then used as the basis of a proximity detection mechanism.

2. A method of proximity detection of wireless network communications devices operating in the FCC 5GHz (U-NIl) or FCC 2.4GHz (ISM) frequency bands the steps of: imitating a corresponding communications device searching for a communications partner so that the proximate communication devices offer their unique ID codes and using these unique ID codes are then used as the basis of a proximity detection.

3. A device or method as claimed in any preceding claim where no attempt is made to establish a practical communications link once the unique ID is obtained.

4. A device or method as claimed in any preceding claim where the process of imitating a corresponding communications device searching for a communications partner is performed repeatedly.

5. A device or method as claimed in any preceding claim where the ID code is used to derive a unique or nearly unique ID code in another data format.

6. A device or method as claimed in any preceding claim where the ID code is compressed once obtained.

7. A device or method as claimed in any preceding claim where the ID code is hash-coded once obtained.

8. A device or method as claimed in any preceding claim where the ID code is encrypted once obtained.

9. A device or method as claimed in any preceding claim where the ID code is used to derive a unique or nearly unique ID code in the Weigand data format.

Radio Proximity Sensor Page 5

10. A device or method as claimed in any preceding claim where the detected unique ID code, in its original or derived form, is conveyed to a computer.

11. A device or method as claimed in any preceding claim where the proximate wireless network communication devices use the Bluetooth communications protocol.

12. A device or method as claimed in any preceding claim where the proximate wireless network communication devices use the IEEE 802.11 communications standard.