Brain computer interface

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

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
POTENTI
OMETER
PRE-
AMPLIFIE
R
COMPARA
TOR
BUFFER
DRIVER
RELAY
TRANSMI
TTER

RECEIVER
RF
RECEIVER
BUFFER
DRIVER
RELAY
MICROCON
TROLLER
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

Brain computer interface

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