Inventory management system

A system for cataloguing items disposed within a predefined volume;

• each item of said items having associated therewith a tag;
• each tag having a unique identifier;
• each tag including:
• a tag radio transmitter having a predefined tag transmission range;
• a tag radio receiver having a predefined tag reception range;
• a response logic device;
• said system further including a tag interrogator;
• said tag interrogator including:
• a database;
• an interrogation logic device;
• a tag interrogator transmitter having a predefined tag interrogator transmission range;
• a tag interrogator radio receiver having a predefined tag interrogator reception range;
• each said tag incorporating a low power state from which the tag can be awoken when a signal is sent to the tag;
• the tag radio receiver of a first tag receiving communication from the tag radio transmitter of a second tag when the tag radio receiver of the first tag is within the predefined tag transmission range of the second tag and when the second tag is within the predefined tag reception range of the first tag;
• wherein communication from the tag interrogator is passed from the second tag to the first tag thereby to increase the range of the communication of the tag interrogator.