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BySandeep KSreesh SJaleela CKrishnasree G K

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ABSTRACT

SIMPLE SYSTEM TO CONTROL WHEEL CHAIR FORPARALYSED PATIENTS USING MOTION SENSOR

USES TRIPLE AXIS ACCELEROMETER MMA7660FC [I2C

O/P] FROM FREESCALE SEMICONDUCTORS TO SENSEMOTION

CONTROL EQUIPMENT FITTED ON PATIENTS HEADOR PALM IS USED TO CONTROL WHEEL CHAIR

BUILT AROUND RISC CONTROLLER PIC16F877A FROMMICROCHIP FAMILY

TWO GEARED DC MOTORS ARE USED FOR MOTIONOF PROTOTYPE MODEL

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BLOCK DIAGRAM

MICROCONT

RLOLLER

MOTIONSENSOR

DRIVER

DCMOTOR1

DCMOTOR

2Serial

Interface

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MOTION SENSOR Triple axis Accelerometer MMA7660FC is used to sense motion

Uses MEMS sensing g-cell technology

It gives I2C output for X, Y& Z axis orientation

It acts as I2C slave while microcontroller works as master Slave address for this sensor is 0x4c

I2C write built in address is 0x98

I2C read built in address is 0x99

6 bit output for each axis

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I2C operation

Two wire communication bus developed by PHILIPS

SDA [serial data out], SCL[Serial clk] used lines

Single Master [here pic mc] initiates it. Series of Clk pulses from master

On Start Master sends address of slave to recognise it.

Here sensor acts as slave and its address is 0x4c

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I2C START/STOP

I2C BIT TRANSFER

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CIRCUIT DIAGRAM

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PROGRAM FLOW CHARTSTART

INITIALISESENSOR

READ X,YORIENTATION

IFORIENTAIONLEFT?

TURNMOTOR

LEFT

A

B

DISPLAY VALUES

ON

HYPERTERMINAL

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A

IfORIENTAT

IONRIGHT?

TURNMOTORRIGHT

IF UP?

IF DOWN

TURN BOTHFORWARD

TURN BOTHBACKWARD

YES

YES

YES

NO

NO

B

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ADVANTAGES

Easy to operate

Suitable for handicapped people

Superior level of sensitivity Better shock resistivity

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IMPROVEMENTS

Sensor can be interfaced wireless using RF or zigbee orsimilar communication modules

Sensor can read tilt and shake detection and havegreater scope of applications

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CONCLUSION