Abstract: An electronic sensor system for monitoring activity of objects according to the invention is of the type includes a central electronic unit exchanging encoded information through radio frequencies with at least one transponder, associated with an object to be monitored, in order to check for activity, such as its presence in a defined volume, and emitting an alarm when said encoded information received from the transponder directs the central electronic unit to start the alarm. The central electronic unit selectively corresponds with each transponder in the system and controls whether the transponder operates in stand-by mode or an active phase mode.

Abstract: An electronic sensor system for monitoring activity of objects according to the invention is of the type includes a central electronic unit exchanging encoded information through radio frequencies with at least one transponder, associated with an object to be monitored, in order to check for activity, such as its presence in a defined volume, and emitting an alarm when said encoded information received from the transponder directs the central electronic unit to start the alarm. The central electronic unit selectively corresponds with each transponder in the system and controls whether the transponder operates in stand-by mode or an active phase mode.