Hand gesture based wheel chair movement control

for the disable with MEMS using PWM technique

Presented by:

B. vedavathi(10091A1093) K. rahimunnisa(10091A1064) S.praveen(10091A1059) B.sindhura(10091A1081) S.Vijay kumar(10091A1097)

INTRODUCTION: This project is to develop a wheel chair control

which is useful to the physically disabled person with his hand movement or his hand gesture recognition using MEMS technology.

In MEMS we have Tilt register. When we change the direction, the tilt registers values are changed and that values are given to microcontroller.

Depending on the direction of the MEMS, microcontroller controls the wheel chair directions like LEFT, RIGHT, FRONT, and BACK.

BLOCK DIAGRAM:

BATTERY:

For power supply a lead acid battery is used.

Lead acid

battery

Bridge rectifier

Filter circuit

regulator

Power supply to all sections

3-AXIS ACCELERATION SENSOR:Mems -small and highly sensitive

accelerometer can detect acceleration, inclination and vibration by measuring the motion in the x-,y- and z-axis simultaneously.

Principle of detection: Magnitude of stress along x and y direction

along z-direction

The MEMS 3-axis accelerometer consists of a mass at the center of the sensors chip, which is suspended by 4 beams doped with piezo resistive material.

When the sensor is subjected to acceleration in any direction, the movement of the mass causes the 4 beams to deform and so changes the resistance of in the piezo material . This enables the sensor to detect the acceleration motion.

DC GEARED MOTORS:

The wheelchair can be moved forward and reverse direction using geared motors of 60RPM.

This dc geared motor is driven by h-bridge .

H-bridge:

An H bridge is an electronic circuit  that enables a voltage to be applied across a load in either direction. These circuits are often used in robotics and other applications to allow DC motors to run forwards and backwards.

An H bridge is built with four switches (solid-state or mechanical).

When the switches S1 and S4 (according to the first figure) are closed (and S2 and S3 are open) a positive voltage will be applied across the motor. By opening S1 and S4 switches and closing S2 and S3 switches, this voltage is reversed, allowing reverse operation of the motor.

S1 S2 S3 S4 RESULT 1 0 0 1 MOTOR MOVES RIGHT

0 1 1 0 MOTOR MOVES LEFT

0 0 0 0 MOTOR FREE RUNS

0 1 0 1 MOTOR IN BRAKE CONDITION

1 0 1 0 MOTOR IN BRAKE CONDITION

1 1 0 0 SHOOT-THROUGH

AITS 11 Thank you……

RGM 12

Any

queries….