Research Of Portable EEG Detection System Based On The OMAPL138

The electroencephalogram (EEG) contains a lot of ideological activities information. Thro-ugh testing and research of EEG signal, people can fully understand the activity of brain and thedifferent brain waves which come from different thought, so as to build a good foundation forthe research of Brain-machine interface(BCI). The BCI technology is the experiment that turnsthe virtual EEG into the actual control command.The main purpose is to realize thebrain manipulation of external mechanical device. Brain-computer interface technologyapplication field is very wide. In medical, aerospace and military fields are involved inbrain-computer interface technology.The key difficulties of BCI technology are the detectionand feature extraction of EEG signal. The research of EEG signals have been paid more andmore attention, which in many fields is involved. For example, in medical research area, bydetecting the patient of EEG to diagnose the illness, using the medical equipment which isdesigned by BCI to help patients recovering, in the field of aerospace and military have beenused brain-computer interface technology.After research the development trend of the EEG and the current situation, summarizing theresearch results of EEG detection at home and abroad, this paper builds a set of research ofportable EEG detection system based on the OMAPL138. The algorithm is transplanted to theOMAPL138processor, preprocessing, storage and dynamic display of data. Compared withthe traditional EEG detection system. It increases the flexibility and portable of EEG acquisitionsystem. Compared to the existing portable EEG processing system, from thePC, without life power, the whole system is more portable and miniaturization, easy to carry.Real-time and dynamic waveform display, which is convenient for researchers to observe. TheOMAPL138processor is provided with a backup communications, the data is wirelesstransmission, through the serial port or USB data is transmission. It has a very broad applicationprospects.The EEG signal is very weak, the amplitude is only microvolt level, which in the rangeof10uV-100uV. It is very easy to be interference by all kinds of noise and clutter.Effective EEG signal is hidden in these noise signals. Therefore, the system design of filtercircuit effectively, the detected EEG by filtering pretreatment. First of all, the EEGsignals through the pre-amplification circuit enter the high pass filter, and then through thetwo stage amplifier circuit into a low pass filter.At last, passing the50Hz power frequency notchfilter. At the same time, the system use C language to design FIR digital filter and FFT transformalgorithm.The digital EEG make further filtering and feature extraction. The whole structure isdivided into two parts: transmitting and receiving, the signal that is amplifying and is send out bythe wireless transmission module, the OMAPL138core board control receiving module receives data, and then, do pre-processing, feature extraction, display and storage.