Patent ID: 7389674

Claim:
An energy-autonomous sensor for detection of physical environmental parameters, comprising: a sensor element for detecting the physical environmental parameters; a control circuit for encoding the detected physical environmental parameters; a radio-frequency transmitter producing one of a radio-frequency signal and a radio message to transmit encoded physical environmental parameters and to transmit an ID-number of the sensor; a timer circuit which activates the control circuit, the sensor element and the radio-frequency transmitter at a predetermined time interval, and deactivates said control circuit and said sensor element and said radio-frequency transmitter after a predetermined period of operation, to define a time duration of operation and a time duration associated with an operational pause; and a photovoltaic element which is connected to a storage element to supply power to the storage element, the storage element being configured to store electrical energy and being connected to the timer circuit to provide electrical energy to at least one of the timer circuit, the control circuit, the sensor element and the radio-frequency transmitter; wherein the photovoltaic element is configured such that it is smaller than required for direct operation of the timer circuit, the control circuit, the sensor element and the radio-frequency transmitter.