An object proximity alert system using motion detection having a smart alarm component for receiving a proximity signal from an associated object monitor component. The object monitor includes within its housing a motion detector that monitors the state of motion of the object monitor, and at least one operating instruction that adjusts a property of the transmitted proximity signal in response to a change in the object monitor's motion state. The smart alarm sets off a perceptible alarm through one or more sensory alert mechanisms when the separation distance between the smart charm and object monitor is determined to exceed a threshold alert criterion.