The Research Of Wireless Strain Monitoring System Based On Radio-Frequency Technology

Strain measuring technology has be used to test the structural strain in machinery manufacture, shipbuilding, aerospace and civil engineering, etc. But the former mode has the wire connection to test, which routing is complex, test is low efficiency. So the topic will use the wireless communication technology into Strain measuring, which could solve the difficult routing, and improve the adaptation of the test system.The paper studies the wireless strain monitoring system, which includes two parts: the one is strain acquisition node which contains strain collection and data transmit module. The strain collection module is composed of strain bridge, signal processing and analog-digital conversion circuits, and the data transmit module is composed of ADuC812 and rf module nRF905; The other one is monitoring center which is composed of host computer, STC89C52 and RF receiving module nRF905.In the system, the strain slices are pasted on the measuring points of specimen, connects to bridge circuit. when specimen suffered external force produces deformation, the resistance variation of strain slice turns into voltage change. After passed signal amplifier and low-pass filter, the voltage analog signals are converted into digital signals by ADuC812 micro -converter. Then the RF module nRF905 transmits the digital signals; In the monitoring center, the signals are received by the wireless receive module nRF905, and analysed, processed, displayed and saved after uploaded to the host computer through serial port.Experimental examination of the system is done, the test results show that the system mainly achieves stress and strain signal's real-time collection, wireless transmission is reliable and stable, then the achieving design meets the qualification of the subject.