Patent ID: 6882275

Claim:
A device for triggering an alert or a pre-alert when a normally immobile object is detected to move, the device comprising: measurement means for generating measured values; transmission means receiving the values measured by the measurement means and for transmitting the values to processing means for processing the values, and for transmitting the measured values; message transmission means controlled by the processing means; and monitoring means comprising, means for receiving the message sent by the message transmission means, and means for triggering the alert, wherein the measurement means comprises at least one magnetometer with at least one axis fixed to the object and for measuring a magnetic field along the at least one axis, wherein the processing means accomplishes at least one of (a) calculating a vector magnitude representative of a movement and (b) generating a movement detection signal by comparing the calculated vector magnitude with a threshold vector magnitude, based on a series of measurements from the measurement means, and wherein the means for triggering the alert is coupled to the processing means and sends an alert message on reception of the detection signal from the processing means.