A multifunctional multichip system can operate in a passive mode by using at least one antenna to receive electromagnetic energy and using that energy to perform system functions. The processing significantly improves selectivity and specificity of detection objects and events in a series of motions that may precede a patient who is at elevated risk of falling. The nozzle includes an air inlet, an air outlet, and an annular casing which defines a bore through which air from outside the fan is drawn by air emitted from the air outlet.