Development Of Electroencephalograph Signals Acquisition System Based On Universal Serial Bus Interface

Electroencephalograph (EEG) is record which reflects regular electric action of brain cells groups, of which transverse axis represents time, and vertical y-axis represents value of potential generated by brain cells. Electroencephalograph is significant for research of brain function, also is useful for clinic diagnosis for brain disease. It is used for medicine in order to check brain function or diagnose brain trauma, brain thrombus, heteroplasia, metabolic disease and endocrine disease, especially efficient epileptic disease. Recently, brain mechanic interface (BMI) is spotlight among scientific research, and its application in movement rehabilitation engineering extremely interested researchers. The special signals is extracted from electroencephalograph signals which control the movement mechanic hand or wheelchair device etc. Traditional electroencephalograph recorder finished record wave by a tracer. Nowadays it is common to use a personal computer and a printer to record electroencephalograph, and data acquisition card adopted PCI bus instead of ISA bus in earlier products. Universal serial bus (USB) is outstanding in convenient connection and plug & play which has widely won application. Here we develop a device realizing electroencephalograph signals acquisition based on USB interface. This paper introduced development of electroencephalograph signals acquisition system based on USB interface. Its hardware mainly consist of amplifier, filter, photoelectric isolation, analog to digital conversion, data acquisition by single chip processor and USB communication module. The primary components and chips being used include high precision INA114 produced by TI company for the first input, high precision feedback photo coupler HCNR201 produced by HP corporation for photoelectric isolation, ADS8364 produced by TI company for A/D conversion, AN2132Q (including CPU & USB SIE) produced by Cypress company for control and USB communication. The software of the system contains data acquisition program for single chip processor, USB interface communication program, device driver program and windows applicant program. The main programming tool includes Keil C for single chip processor, EZ-USB Control Panel debugging USB interface communication program, Driver Studio for device driver development and Visual C++ 6.0 for windows applicant program.