1. Advanced Wheel chair with voice
recognition and transmission
c pujitha,m sukanya
Electronics & Communication Dept.
PADMAVATI UNIVERSITY
tirupati, India
chinthalapujitha@gmail.com
Abstract— The paper describes a automatically controlled wheel chair for disabled
people. The chair enables the user to move his chair using his finger & hand. The flex
sensors and accelerometer on the glove generate ASL coded signals which are decoded &
control the chair. It also display the information intended by the user. Additionally
theinformation is also converts to speech. The wireless link between the glove & wheel
chair enables any person to operate. This advanced wheelchair system is used for
physically disabled and deaf/dumb people move around easily and to communicate with
normal people.
Index Terms—Accelerometer and Flex sensor controlled wheel
chair, Speech Synthesizer, American Sign Language, XBee.
I. INTRODUCTION
American Sign Language Detection and Voice Conversion is implementation for
designing a system in which sensor glove is used to detect the signs of ASL performed by
a user. It is considered as the standard for communication among deaf/dumb people. Over
100 million people worldwide, with physical disabilities require the assistance of a
wheelchair. Two different hardware boards are available. One is placed in the wheelchair
(receiver side/robot side) and second one is placed at the user side (transmitter side).
Once the voltage is received by the microcontroller, it needs to be transmitted over to the
other side of the system, which is the wheelchair. This is done by the transmitting circuit
present on the hand-glove, hence realizing wireless communication between the chair
andthe glove. The glove comprises flex sensors, accelerometer on the back of the palm to
measure dynamic and static gestures which detect the position of each finger by
monitoring the bending of the flex sensors mounted on them. The sensor circuit output is
then sent to Microcontroller through ADC. The pre-stored activated and displayed on the
LCD and voice using speaker. These data will provide a medium for normal as well as
deaf/dumb people to communicate more easily in the society.
The different directions of motions possible are:
1) Forward: Both the motors in the forward direction.
2) Backward: Both the motors in the reverse direction.
3) Left: Left motor backward direction, Right motor in the

2. forward direction.
4) Right: Right motor backward direction, Left motor in the
forward direction.
In this project we have used two microcontrollers, a speech IC, speaker to produce the
output, LCD display (16x2), ZigBee, Flex sensors.
BLOCK DIAGRAM
The block diagram of a Wireless American Sign Language Detection and Voice
Conversion Flex Sensor Controlled wheelchair for Physically Disable and Deaf/Dumb
People. Flex sensors which are variable resistance sensor which are placed on each of the
fingers. This sensor is used to determine the position/angle of the fingers. Accelerometer
is directly interfaced to the digital ports. Microcontroller processes the data for each
particular gesture made. Microcontroller is used to read data from different sensors and
then transmit these data to the receiver side. If compared data get the matched then
matched gesture sent with text to LCD screen and speaker

3. SYSTEM DESCRIPTION
A. Flex Sensor
The Flex sensors are sensors that changes in resistance depending on the amount of bend
on the sensor. They convert the change in bend to electrical resistance; the more the bend,
the more the resistance value increase. They are usually in the form of a thin strip from
1’’ to 5” long that vary in resistance; they could be made in a unidirectional or
bidirectional form. As Flex sensors are analog resistors, they work as variable analog
voltage dividers: when the substrate is bent, the sensor produces a resistance output
relative to the bend radius The impedance buffer in the Basic Flex Sensor Circuit is a
single sided Operational Amplifier, used with these sensors because the low bias current
of the Op-Amp reduces error due to source impedance of the flex sensor as voltage
divider . Suggested Op-Amps are the LM358 or LM324.

4. CHARACTERISTICS OF FLEX SENSOR

5. fig:flex sensor glove
B. Accelerometer Sensor
To detect the letters 'J' and 'Z', which require movement in addition to hand position, we
add an accelerometer to detect the movement of the glove/hand. The accelerometer
ADXL335 is a small, thin, low power, complete 3-axis accelerometer with signal

6. conditioned voltage outputs. The output signals are analog voltages that are proportional
to acceleration. The accelerometer can measure the static acceleration of gravity in tilt-
sensing applications as well as dynamic acceleration resulting from motion, shock, or
vibration. Deflection of the structure is measured using a differential capacitor that
consists of independent fixed plates and plates attached to the moving mass. The fixed
plates are driven by 180° out-of-phase square waves. Acceleration deflects the moving
mass and unbalances the differential capacitor resulting in a sensor output whose
amplitude is proportional to acceleration.
C. Microcontroller and wifi module
The AT89S51 is a low-power, high-performance 8-bit microcontroller with 4K bytes of
in System Programmable Flash memory. It is compatible with the industry-standard
80C51 instruction set and pin out. The on-chip Flash allows the program memory to be
reprogrammed in-system. AT89S51 is a powerful microcontroller which provides a
highly-flexible and cost-effective solution to many embedded control applications. The
AT89S51 provides the following standard features: 4K bytes of Flash, 128 bytes of
RAM, 32 I/O lines, two data pointers, two 16-bit timer/counters, a five-vector two level
interrupt architecture, a full duplex serial port, on-chip oscillator, and clock circuitry. The
Idle Mode stops the CPU while allowing the RAM, timer/counters, serial port, and
interrupt system to continue functioning. The Power-down mode saves the RAM con-
tents but freeze the oscillator, disabling all other chip functions until the next external
interrupt or hardware reset. WiFi Modules connects to your host CPU over
SPI/SDIO/UART interface and helps you to save one extra CPU cost by directly
integrating the low footprint SDK and network stack on your CPU. These low-power,
low-cost modules are sized to fit within your products. Multiple antenna options and
reference starter kits are available to minimize costs and accelerate time-to-mark.The rf
Modules was engineered to meet IEEE 802.15.4 standards and support the unique needs
of low-cost, low-power wireless sensor networks. The modules require minimal power
and provide reliable delivery of data between devices. The modules operate within the
ISM 2.4 GHz frequency band and are pin-for-pin compatible with each other and these
modules are embedded solutions providing wireless end-point connectivity to devices.
They are designed for specifically to replace the proliferation of individual remote
controls
D. Display Unit
A 16 × 2 line LCD is used to display the status of two inputs (flex sensors, speech
synthesis). LCD requires less power, provides backlight during lowlight vision. LCD is
interfaced with a microcontroller in byte mode (8-bits of command/data are transmitted at
a time).
E. Speech Synthesizer
This module of the system is consisted of a microcontroller (AT89C51), a SP0256
(speech synthesizer) IC, amplifier circuitry and a speaker. The function of this module is
to produce voice against the respective gesture. The microcontroller receives the eight bit
data from the “bend detection” module. It compares the eight bit data with the predefined
values. On the basis of this comparison the microcontroller comes to know that which
gesture does the hand make. Now the microcontroller knows that which data is send by

7. the bend detection module, and what the meaning ofthis data is. Meaning means that the
microcontroller knows if the hand is making some defined gesture and what should the
system speak. The output of the amplifier is given to the speaker.
RESULT AND DISCUSSION
Advanced wheel chair is the prototype for establishing easy communication between
deaf/dumb people and normal people. This will surely help them to be independent and
confidently express them. When a person wears a band fixed with accelerometer and
bends is finger the wheelchair moves in corresponding direction based on the bend of the
finger. For different sign detection and conversion better and sophisticated
implementation, a matrix technique has been implemented. Here, each sensor bend is
divided in three distinct parts, viz. Range of values, associated with each bend of the
respective sensor is calculated and its digital equivalent is f o un d out. Table 1 below,
depicts the Bend characteristics corresponding to each of the five fingers, viz. thumb,
index, middle, ring and little. Though the corresponding concept behind the idea of the
matrix technique.The accelerometer sensor is calibrated such that it produces particular
analog voltage for a corresponding tilt. At the end of the research it is expected that we
get higher accuracy (upto 90-95%) of hand gesture recognition by using sensory data
gloves. So we have combined flex sensor and accelerometer sensors data together and
then fading to the microcontroller. These both sensor increases accuracy, reliability as
well as comfort to the user .
CONCLUSION AND FUTURE WORK
This automatically controlled chair is a useful for speech impaired and partially paralysed

8. patients which fill the communication gap between patients, doctors and relatives. They
can move around easily and any person can operate this chair by his finger movements. It
will give dumb a voice to speak for their needs and to express their gesture. System
efficiency is improved with wireless transmission is help in long distance
communication. In future work of the system supporting more no of sign, different
language mode. The various operations like taking turns, starting or stopping vehicles can
be implemented efficiently. This system is going to develop as hardware and software.
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