Development of BCI DAQ Hardware and Software

Abstract

Brain-Computer Interface (BCI) is a technology in which researchers have the intention to achieve direct communication between the human brain and the computer. A brain that contains millions of neurons and each has related to the different activity of human body like moving hand, walking, thinking, sleeping, etc. So, the brain is a very important part of the human body and if there is any dysfunction happening to it our whole body gets affected. That is called seizures or epilepsy which occurs one in every 100 people. Thus, BCI technology helps in detecting seizures and to find what type of seizure it is. The BCI DAQ (Data Acquisition) hardware system has dedicated sensors for measurements of electrical activity in which signal range is from microvolt to order of millivolts as human brain signals are in millivolts or so. So, the main idea is to get data from sensors/electrodes that are being attached to human brain scalp and displaying or analyzing it on PC(personal computer) which is called EEG(Electroencephalography) technology. EEG is a method of the monitoring/analyzing the electrical pattern of neurons in the brain. Through this process researchers or doctors can find out if a person is having epilepsy or not and operate patient accordingly. EEG Technology helps to diagnose conditions like dizziness, brain tumor, injuries related to head, epilepsy-brain disorder, sleeping problems, seizures, headaches, it can also help to confirm brain death. Sensors being used in this project are EEG AE (Active Electrode). DAQ(Data Acquisition) hardware being used is analog circuit EEG-SMT, which is nothing but interface hardware that strengthens brain signals and makes it visible/understand- able, which includes an operational amplifier for enhancement and fillter for convert- ing the signal from analog to digital. EEG-SMT includes ADCs up to 32 channels, DAC up to 2 channels and 32 digital I/O, ICSP (In Circuit Serial Programming). SPI (Serial Peripheral Interface) protocol is being used for short distance communi- cation between ADC channels and microcontroller STM32. It also includes USB and RS232 connectivity to PC for data transfer using open standard protocol. In this project, the conceptual design for BCI hardware is made and its circuit diagram is developed.PCB artwork is designed and developed. The testing of hard- ware that is EEG Sensor has been done. Finally, processing of BCI related basic minimum data processing in microcontroller STM32 and displayed on PC through RS232 connectivity. Software electric guru and the open vibe are used to analyze signals. Furthermore, in this thesis software part of EEG classification is done in MAT- LAB 2016a software. In this, signal processing is being done on already available EEG data, .mat file that is loaded in MATLAB and through the appropriate algo- rithm, EEG classification is done.