Brain computer interface

DEVELOPMENT OF PORTABLE WIRELESS BRAIN-

COMPUTER INTERFACE WITH EMBEDDED SYSTEM

INTRODUCTION A Brain Computer Interface (BCI) is a computer-based system that

acquires brain signals, analyzes them, and translates them into commands that are transmitted to an output device to carry out a desired action.

The use of wireless transmission and reception helps us to eliminate the wires which can introduce artifacts.

The usage of embedded system helps in more flexibility of the interface and also in use of more peripheral devices. They are used to control the devices.

Real time and embedded systems offer a better platform to build wearable and inexpensive BCI systems

BRAIN-COMPUTER INTERFACE(BCI)

A BCI is a computer-based system that acquires brain signals, analyzes them, and translates them into commands that are relayed to an output device to carry out a desired action.. A brain–computer interface (BCI), often called a mind-machine interface (MMI), or sometimes called a direct neural interface or a brain–machine interface (BMI),

a direct communication pathway

between the brain and an external

device.

ELECTRIC BRAIN

Brain is mostly composed of neurons interconnected

to each other forming an enormous network.

They communicate together through

their axons using small electric impulses.

Neurons generate electric potential

variations of a brain active region during

a particular mental activity.

Electroencephalography (EEG) is the recording of electrical activity along the scalp.

EEG AND ITS CLASSIFICATION

Delta wave

Theta wave

Alpha wave

Beta wave

BCI INPUT-OUTPUT

OBJECTIVE

To wirelessly transmit and receive signal.

To eliminate the wired communication between modules for data

transfer.

To analyze various stages of sleep in human being.

PROBLEM DEFINITION Brain is incredibly complex hence acquisition of these signals is

difficult.

Brain signal is weak and prone to interference.

ASSUMPTION In our project we are assuming that the brain signals acquired are due

to the resistances generated at the scalp and are then mere voltages. Hence we are using the potentiometer to vary the resistances and obtain them in the form of voltage which can be transmitted and received wirelessly.

DESIGN AND PROJECT METHODOLOGY

TRANSMITTER

POTENTIOMETE

R

PRE-AMPLIFIER

COMPARATOR

BUFFER

DRIVER

RELAY

TRANSMITT

ER

RECEIVER

RF RECEIVER

BUFFER DRIVER RELAY

MICROCONTROLLER

BUFFER DRIVER RELAY

BULB

DISPLAY

COMPARATOR The comparator used in our project is LM 3915.

We are varying the resistances to generate the voltages.

These voltages are the input to the transmitter.

It compares the threshold voltage with the incoming input voltages and transmits it to microcontroller.

PRE-AMPLIFIER The pre-amplifier is used to amplify the signals.

Current amplifier application need very low input bias current and CA3140 is one of the suitable pre-amp for this purpose.

The signals taken from the potentiometer are amplified and given to the comparator .

RF MODULE

The transmitter/receiver (Tx/ Rx) pair operates at a frequency of 434 MHz

The project uses an RF transmitter and receiver for fulfilling the wireless transmission and reception objective.

An RF transmitter generates radio frequency waves

High performance with no interference of the same remote with different frequency.

The whole circuit function with the help of transistors and the supply to the transmitter is given by a 9V/12V DC source.

Transmission through RF better than infrared ? ?

Firstly, signals through RF can travel through larger distances making it suitable for long range applications.

Also, while IR mostly operates in line-of-sight mode, RF signals can travel even when there is an obstruction between transmitter & receiver.

RF transmission is more strong and reliable than IR transmission.

RF communication uses a specific frequency unlike IR signals which are affected by other IR emitting sources

MICROCONTROLLER UNIT

The microcontroller used in this is 89C51.

It belongs to Atmel 8051 family.

The ATmel 89C51 is a low-power, high-performance CMOS 8-bit microcomputer with 4 K bytes of Flash programmable and erasable read only memory (PEROM).

In 40-pin AT89C51 there are four ports designated as P1, P2, P3 and P0.

Port P0 and P2 are also used to provide low byte and high byte addresses, respectively.

Features of 89C51

Compatible with MCS-51 Products. 4K Bytes of In-System Reprogrammable Flash Memory. Fully Static Operation: 0 Hz to 24 MHz. Three-level Program Memory Lock. 12 8 x 8 Internal RAM 32. Programmable I/O Lines. Two 16 bit Timer/Counters. Six Interrupt Sources Programmable Serial Channel. Low-power Idle and Power-down Modes 4 0-pin DIP.

DEVICE OUTPUT We are displaying the type of waveform received on the LCD display.

Based on the EEG activity of brain we are varying the intensity of light of bulb.

Drowsiness is indicated by low intensity.

Alertness is indicated by the high intensity.

ADVANTAGES

Enables wireless transmission of the signals

Through our project it is possible to analyze the sleep stages of the brain.

Improves the mobility of the BCI system.

DISADVANTAGES Research is still in beginning stage.

Current technology is crude.

Ethical issues may prevent its development.

APPLICATIONS Provide enhanced control of devices such as wheelchairs, vehicles, or

assistance for people with disabilities.

Provide additional channel of control in computer games.

Paralyzed patients are able to interact with the environment using no muscular contractions.

Handicap person can also access its

devices without using wired

communication.

CONCLUSION Brain-computer interfaces may eventually be used routinely to

replace or restore useful function for people severely disabled by neuromuscular disorders and to augment natural motor outputs for pilots, surgeons and other highly skilled professionals.

As we have shown that data can be transmitted and received wirelessly , hence no need of too many wires to acquire the signals and get respective output.

The BCI system is helpful for paralyzed patients and for studying various disorders.

REFERENCES

Electroencephalography, Wikipedia, the free encyclopedia,http://en.wikipedia.org/wiki/Electroencephalography

Chin-Teng Lin, Fellow, IEEE Department of Electrical and Control Engineering Computer Science, National Chiao-Tung University Hsin-Chu, Taiwan, R.O.C. Development of Portable Wireless Brain Computer Interface with Embedded Systems.

Chin-Teng Lin, Li-Wei Ko, Che-Jui Chang, Yu-Te Wang, Chia-Hsin Chung, Fu-Shu Yang, Jeng-Ren Duann, Tzyy-Ping Jung, and Jin-Chern Chiou; Wearable and Wireless Brain-Computer Interface and Its Application.

 BCI review -a tour of research lab Jacquas. Vidal (1977). 

"Real-Time Detection of Brain Events in EEG". IEEE Proceedings