eog controlled wheelchair
DESCRIPTION
The wheel chair is controlled by movement of iris for disabled personsTRANSCRIPT
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