Patent ID: 8390274

Claim:
A method for determining a person's activity in surroundings equipped with electrical appliances that are switchable, in response to a command from the person, between an ‘on’ mode, in which the electrical appliance radiates an electromagnetic field corresponding to a characteristic magnetic signature, and an ‘off’ mode, in which the electrical appliance does not radiate any electromagnetic field or radiates an electromagnetic field corresponding to a magnetic signature different from the magnetic signature characterizing the same appliance in ‘on’ mode, wherein the method comprises: measuring a magnetic field produced by one of the electrical appliances by means of a magnetometer carried by the person, identifying an electrical appliance in ‘on’ mode in proximity to the magnetometer by comparing the measured magnetic field with the pre-recorded magnetic signatures of electrical appliances in ‘on’ mode, and determining the activity the person engages in on the basis of a pre-recorded activity identifier associated with the electrical appliance identified as being in ‘on’ mode on the basis of its magnetic signature.