an iron comprises a heating element , heating - control for the heating element , and a motion detector . the motion detector can be an electrostatic detector which determines an amount of electrostatic charges present at the fabric . the motion detector can be a humidity detector which detects a resistivity of the fabric between two electrodes which are in contact with the fabric . a counting circuit calculates a number of halfwaves of an electric signal supplied by one of the detectors and determines whether the iron is in use or is not in use . moreover , the degree of humidity of the fabric can be determined by a measurement circuit .