An apparatus or a method for detecting activity quantity of an object includes a sense unit, a count unit, a trigger unit, and a radio circuit. The sense unit senses movements of the object, and generates a sensing signal based on the sensed movements. The count unit receives the sensing signal from the sense unit, counts a number of the movements from the sensing signal, and generates a movement number signal including the number of the movements. The trigger unit generates a trigger signal based on whether one or more trigger conditions are satisfied. The radio circuit is triggered in response to the trigger signal, to generate an activity quantity signal based on the movement number signal and ID information corresponding to the object.