Patent ID: 7786887

Claim:
An autonomous-power radio device, which is physically coupled to an electromagnetic energy converter to provide electric current to an autonomous-power radio switch or autonomous-power radio sensor, wherein the electromagnetic energy converter comprises: a permanent magnet, a moving element, a soft-magnetic element, and an electric coil that surrounds at least a part of the soft-magnetic element, wherein said moving element is adapted so that any movement of the moving element from a first rest position or from a second rest position leads to opening or to closing of a magnetic circuit which is formed by the permanent magnet and the soft-magnetic element, wherein the autonomous-power radio switch or autonomous-power radio sensor is combined physically with the energy converter to form a compact unit configured to produce a radio signal, and wherein said moving element comprises a spring element that makes the second rest position unstable, so that the moving element returns to the first rest position after a movement to the second rest position.