EOG CONTROLLED WHEELCHAIR

PRESENTED BY; AROMAL.S.S

ATHIRA DAS.A.JJERSON ALEX

SUJU SURENDRAN

INTRODUCTION

o EOG (Electro Oculo Graphy) o Each movement of eye

gives different EOG signals.o This EOG signals are

processed by using several amplifiers and filters.

o By using a microcontroller, drives the motor.

EOG

It is a technique for measuring the resting potential of the eye.

The electrooculogram (EOG) signal is derived from the polarization potential, also known as the Corneal-Retinal Potential (CRP),

The EOG value varies from 50 to 3500 µV with a frequency range of about dc-100 Hz.

•AgCl electrodes are used •it converts bio-potential signals into electrical signals•AgCl quickly saturates and comes to equilibrium.•Ag is goodmetal for metallicskin surface electrodes.•Contact impedance is less than 10 kΩ over the frequency range of 30–200 Hz .

• a reference/ground electrode is placed on the forehead;•electrodes are placed on the right and left temples for horizontal (lateral) eye movement•electrodes are placed on the above and below temples for vertical eye movement.

Noise and disturbances in EOG signals External noise due to radiations.DC drift due to electrode contact50Hz power line interference

Instrumentation amplifier

•provides initial amplification•Rejects common noise signals,

DC drift remover

•Eliminates DC drift due to electrode contact.•A LPF in the feedback path and subtractor

Non inverting amplifier

EOG signal will not loss because of the attenuation in high order filterGain approximately 100

5th order Bessel Low Pass Filter

Cutoff frequency is 31HzIt pass 0.15-31Hz band

50 Hz Notch filter

Used to remove 50Hz power interferenceIt is used for rejecting unwanted signals that are on a particular frequency

Rectifier & Clipping Circuits

analog voltage for the microcontroller must be between 0 and 5 VRectifier is used for differentiate Left , Right & Blink signals

Digitisation and Controller

•To provide digitization to the analog EOG signals obtained and transferred to a µC (ATmega32L).•16 MHz clock frequency•10 bit digital resolution

Motor driving circuit

L 2 9 3 D

12345678

1 61 51 41 31 21 11 0

9

1 E 2 . 2 W

1 2 V B A TT

R 0

R 1

L 0

L 1

M

M

EN 1,2

EN 3,4

VCC1

VCC2

I/P 1

I/P 2

O/P1

O/P2

GNDGND

GNDGND

I/P3

I/P4

O/P3

O/P4

FROM ARDUINO

MOTOR DRIVING CIRCUIT

65RPM DC MOTOR

65RPM DC MOTOR

•L293D IC

VIDEO PRESENTATION

APPLICATIONSWHEELCHAIRCOMPUTER CONTROLHOUSE HOLD

EQUIPMENTCONTOLMOBILE PHONE CONTROLFOR HANDICAPED PEOPLEAUTOMOBILE DRIVING CONTROLENTERTAINMENT

CONCLUSION This EOG based HMI allows the patients to

generate decisions by means of simple eye movements , without the need of sophisticated equipments.

The EOG-based system seems more efficient than EEG based systems. It must be noted that the solution for the EOG system is extremely cheap when compared to the EEG solution.

Patients could be able to move around with the help of wheelchair any where, according to their eye movements.

THANK YOU