Self-powered wireless tranducer

摘要

A self-powered wireless transducer (10) is disclosed for monitoring external physical conditions, such as excessive vibrations in a bearing. The transducer includes an energy conversion source (16), such as a piezoelectric sensor to sense the external physical condition and create a power and characteristic signal that is used to power an RF transmitting circuit (28). A transmitter (30) is provided to transmit signals indicative of the external physical condition, or changes in that physical condition, such as increased vibrations in a bearing to detect bearing faults before a breakdown. In this manner, the monitored machinery can be shutdown in an orderly manner and preventative maintenance can be completed. The self-powered wireless transducer (10) includes an voltage storage device (24) to receive electrical voltage from the piezoelectric sensor (16) and a voltage detector (26) to detect the level of voltage on the voltage storage device (24). Once the voltage detector (26) detects a level of voltage at a predetermined level, an oscillating transmitting circuit (28) is activated for a brief hysteresis period of the voltage detector (26). The information transmitted not only includes any fault detection, it also includes an address of the origin of the transmission.