The invention is a radio frequency identity detector (RFID)-based system that assists a user in location of an item, in response to an electronic query for the status of the item. The item(s) being sought may be a book on a library shelf, an item from a store inventory, a legal or financial document, a medical record, a weapon system or weapon component (presumably) located in an armory, or similar item.

Each item is tagged by an RFID, which does not require a battery, but is preferably powered using an electromagnetic coil that is embedded in, or associated with, the item. The shelving, or other container, provides an alternating electromagnetic field to power the embedded coils, and can identify the item location if the item is on, or adjacent to, the shelving/container, even if the item is not in its assigned location. Each coil includes a low-power, programmable chip containing relevant information on the item (ID number, class to which the item belongs, present status of the item, relevant item characteristics, recent activity affecting the item, etc.). Removal of the item from the shelf/container may first require entry of specified information, including but not limited to user name, user contact information, user priority level (if applicable), date the item was removed, and user authentication information. An associated light emitting diode (LED) array containing different colored LED light sources is optionally included for visual indication of location(s) of the item.

A desired item is specified and/or categorized using a database system with a computer interface. The interface may be a portable interrogator wireless electronic unit that communicates with the database, and with the item(s) sought. When the portable interrogator unit queries an RFID tag, the computer interface downloads information on the item from the database, and/or from the shelving/container (e.g. availability and/or recent location and/or present status of the item). Optionally, based upon a color code scheme assigned to the particular handheld unit, the shelving/container LED array displays the corresponding distinguishable color scheme wherever the item(s) is/are located.

This system can also provide security for an inventory of weapon systems, weapon components, and biological/ mechanical warfare substances or other sensitive items that require extreme protection. In this instance, the inventory receptacle is powered continuously, and each protected item emits a unique, encrypted code associated with the item, when the item is on, in, or adjacent to the receptacle at its assigned location. When the protected item is not on or adjacent to the receptacle at its assigned location, or is located elsewhere on or adjacent to the receptacle, an alarm or notification signal is issued by the system, indicating when the item was last sensed at its assigned location. Use of an encrypted code of appropriate complexity can minimize or eliminate the possibility of “spoofing” to cover absence of the protected item.

Entry of an encrypted password allowing access to the protected item could be used to avoid prompt issuance of an alarm signal.

This work was done by Stevan M. Spremo and Usen E. Udoh of Ames Research Center. Inquiries concerning rights for the commercial use of this invention should be addressed to

the Ames Technology Partnerships Division at 1-855-NASA-BIZ (1-855-6272-249) or This email address is being protected from spambots. You need JavaScript enabled to view it..

Refer to ARC-15684-1.

NASA Tech Briefs Magazine

This article first appeared in the February, 2014 issue of NASA Tech Briefs Magazine.

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