Studies On The Measurement Of Electromyograhy Based On Wireless Sensor Network

When people do any kind of sports, we can use the surface electrode to acquisite thesignal from the surface of the muscle which participated in the sport, we can call the signalSurface Electromyography signal. Surface Electromyography is a kind of biologicalelectricity which transfers under the surface skin when muscle activities. So in recentyears, there are more and more researchers began to study it. And the measurement andanalysis of SEMG has an important meaning for the Clinical diagnosis, rehabilitationmedicine and sports medicine. Wireless Sensor Network is composed of multiple nodes, itintegrates sensors, computers, network communications, wireless transmission andembedded technology, it can also collect real-time information in the network and monitorthe state of nodes. The scheme will solve the disadvantages of traditional SEMGmeasurement system, such as mobility is poor, vulnerable to the limitation of the data line,maintenance and use is inconvenience, etc. So miniaturization, portable of medicalequipment is a trend. SEMG measurement system based on wireless network in flexibility,real-time, remote operation on performance greatly improved.This thesis designed a SEMG signal acquisition system based on wireless network.Itmainly includes the signal pretreatment system, wireless transmission system andcomputer, etc. Thereinto, the signal pretreatment system includes the preamplifier circuit,the high-pass filter, the low pass filter, the power frequency notch filter, the Secondaryamplifier circuit, the level uplift circuit. After the original SEMG signal is processed bythe signal pretreatment system, the Signal-to-noise is greatly improved. That could getready for the following sampling, transmission and display. In addition, the low frequencynoise has been filtered out in preamplifier circuit, the baseline migration can be effectivelyrestrained, and can avoid the instrument amplifier from the risk of burning out. MSP430MCU is the core processing chip of the wireless transmission system. And nRF905is usedtransmissing and receiving SEMG signal, and then communicated with the serial port ofthe computer. The digital signal is displayed on the host computer. It is easy to analysisand research. In this thesis, we use the system to acquisite the SEMG signal from the flexor carpiulnaris, flexor carpi radialis and so on. Then denoise the signal using the wavelettransform, and select soft thresholding method which is suitable for the SEMG signaldenoising. Then we extract features from the time domain and frequency domain.