A smart cage for behavioral experiments on small freely behaving animal subjects

The EnerCage system is designed to enable electrophysiology experiments of any duration in experimental arenas of any size. Optimized overlapping planar spiral coils (PSCs) provide closed-loop wireless power and data to a mobile unit on a small, freely behaving animal subject. The system tracks the location of the mobile unit with an array of 3-axis magnetic sensors and only activates the closest PSC, thereby reducing power dissipation and heat within the cage. A control algorithm collects data from all the sensors, organizes it by physical location, and systematically compares the magnitudes of each to two thresholds to determine the location of a small magnetic tracer embedded in the mobile unit. An in vivo experiment was conducted for one hour using a 1.03 × 0.9 m² EnerCage prototype in a physiology lab, where the system was able to continuously deliver 20 mW to a dummy load and maintain a steady 4V supply on the rat headstage (mobile unit).