Aacellerometer

Hand Gesture Recognition For Robot Control
1
ABSTRACT
Today human-machine interaction is moving away from mouse and pen and is becoming
pervasive and much more compatible with the physical world. With each passing day the gap
between machines and humans is being reduced with the introduction of new technologies to ease
the standard of living. Gestures have played a vital role in diminishing this abyss. In this project, a
rigorous analysis of “Human-Machine Interaction” using gestures has been presented. Gestures
can be captured with the help of an accelerometer.
The project describes a Accelerometer based Gesture Controlled Robot is a kind of robot that can
be by our hand gestures rather than an ordinary old switches or keypad. In Future there is a chance
of making robots that can interact with humans in an natural manner. Hence our target interest is
with hand motion based gesture interfaces. An innovative Formula for gesture recognition is
developed for identifying the distinct
action signs made through hand movement. In order to full-fill our requirement a program has
been written and executed using a microcontroller system. Upon noticing the results of
experimentation proves that our gesture formula is very competent and it‟s also enhance the
natural way of intelligence and also assembled in a simple hardware circuit.
The goal of this project is development of a sensor capable of measuring human hand acceleration.
One of the important tests of this project is demonstrating the sensor is capable of measuring
involuntary hand acceleration and would be useful in applications measuring involuntary hand
acceleration.
The involuntary hand motion test was made by mounting the sensor on the fingertip of a normal
subject. The test subject held their hand as still as possible with the hand kept horizontal, and data
was acquired at different axis for different movement of hand. The standard deviations of the
accelerations of two axes were measured relative to a control test with the sensor stationary on a
tabletop.

2
INTRODUCTION
Technology, is today, imbibed for accomplishment of several tasks of varied complexity,
in almost all walks of life. The society as a whole is exquisitely dependent on science and
technology. Technology has played a very significant role in improving the quality of life. One
way through which this is done is by automating several tasks using complex logic to simplify the
work.Gesture recognition has been a research area which received much attention from many
research communities such as human computer interaction and image processing
The keyboard and mouse are currently the main interfaces between man and computer. In other
areas where 3D information is required, such as computer games, robotics and design, other
mechanical devices such as roller-balls, joysticks and data-gloves are used. The main motto of this
project is to make robot realize the human gesture, thereby it bridge the gap between robot and
human. Human gesture enhances human-robot interaction by making it independent from input
devices. Robotic system can be controlled manually, or it may be autonomous. Robotic hand can
be controlled remotely by hand gesture. Research in this field has taken place, sensing hand
movements and controlling robotic arm has been developed.
The increase in human machine interactions in our daily lives has made user interface technology
progressively more important. Physical gestures as intuitive expressions will greatly ease the
interaction process and enable humans to more naturally command computers or machines.
A gesture recognition system could be used in any of the following areas:
 Man-machine interface: using hand gestures to control the computer mouse and/or
keyboard functions. An example of this, which has been implemented in this
project,controls various keyboard and mouse functions using gestures alone.
 3D animation: Rapid and simple conversion of hand movements into 3D computer space
for the purposes of computer animation.
 Visualisation: Just as objects can be visually examined by rotating them with the hand, so
it would be advantageous if virtual 3D objects (displayed on the computer screen) could be
manipulated by rotating the hand in space .
 Computer games: Using the hand to interact with computer games would be more natural
for many applications. Control of mechanical systems (such as robotics): Using the hand to
remotely control a manipulator.

3
LITERATURE REVIEW
There are various ways in which a robot may be controlled. In the past there have been
many researchers working to control robot through computer terminals, Joysticks, even interfacing
them with the internet so they can be controlled from anywhere in the world.
In our project robot controlled by a central controller which makes uses of Hand gesture,
Movement Sensors(Accelerometers ADXL 335), Atmega16 Microcontroller,L293d,dc motor etc
values taken in from the terminal that are entered by the user at the terminal to move the arm to a
particular coordinates in space. This Project represents a simple accelerometer controlled by hand
gesture using Atmega16 powered embedded system as the core of this robot .In this project robot
controlled is done by hand movement such as accelerometer ADXL 335 sensor is kept on the top
of the hand. For particular direction of hand the robot move in different direction such as forward,
backward left and right direction. The accelerometer ADXL 335 sensor can measure the
magnitude and direction of gravity in addition to movement induced acceleration. In order to
calibrate the accelerometer we rotate the devices sensitive axis with respect to gravity and use the
resultant signal as an absolute measurement. In this project we have proposed automatic gesture
detection using accelerometer once a gesture is recognized a command signal is generated and
sent to microcontroller. Already a program for signal detection is burned on microcontroller. Once
the command signal is received by robot it works accordingly to the pre-defined function unless
any new signal is received again. The robot does not require training because the robotic arm is
fully controlled by the user. This interfacing is done using wired communication but it can easily
be switched to wireless with ease.

4
METHODOLOGY
Our proposed hardware system involves following steps-
Step 1: After detecting gesture command analog signal of accelerometer ADXL 335 sensor is
send to the Atmega16 microcontroller.
Step 2: As soon as the Analog signal is obtained by the microcontroller it is converted into the
Digital signal.
.Step 3: L293D motor driver circuit takes digital signal as an input from the microcontroller and
gives digital output to the DC motors of the robot.
Step 5: LCD display different coordinate of X-Y axis on the basis of different gesture of the hand
.
In our hardware Accelerometer is kept on the top of the hand so when hand is moved on the
particular direction our robot move in that direction.
For right hand movement robot move in right direction

5
HARDWARE REQUIRED
 Microcontroller Atmega 16(AVR)
 Motor Driver (L293D)
 DC Motors of Robot
 Accelerometer ADXL 335 sensor
SOFTWARE REQUIRED
 Embedded.C

6
Block diagram
ACCELERO
METER
AVR
16

7
SYSTEM COMPONENTS
The different System Components are Camera Unit, Gesture Recognition Unit, Wired
Communication Unit, and Robot Car Unit.
We will take look at each unit sequentially
Robot car unit: Once a hand gesture is recognized, an appropriate command is sent to a robot.
After the robot receives a command, it performs a pre-defined work and keeps doing until a new
command arrives. Movement commands are written as a function in robot specific language.We
define total five gestures to direct the operation of the robot. The operations include the following
motions “Straight”, “Reverse”, “Left”, “Right”, and “Stop”.
Block diagram of robot control
Command
captured by
accelerometer
AVR
microcontrolle
r

8
COMPONENTS USED IN HARDWARE
ATmega 16: The AT refers to Atmel the manufacturer, while Mega represents the
microcontroller belong to MegaAVR category, 16 signifies the memory of the controller.
Atmega16 is equipped with an internal oscillator for driving its clock and by default it is set to
operate at internal calibrated oscillator of 1MHz with maximum frequency of 8Mhz. ATmega16
can be operated using an external crystal oscillator with a maximum frequency of 16MHz (for this
we need to modify the fuse bits). Atmega16 is equipped with an 8 channel ADC (Analog to
Digital Converter) with a resolution of 10-bits. It consists of two 8-bit and one 16-bit
timer/counter.
Features
• High-performance, Low-power
• Advanced RISC Architecture
– 131 Powerful Instructions – Most Single-clock Cycle Execution
– 32 × 8 General Purpose Working Registers
– Fully Static Operation
– Up to 16 MIPS Throughput at 16 MHz
– On-chip 2-cycle Multiplier
• High Endurance Non-volatile Memory segments
– 16 Kbytes of In-System Self-programmable Flash program memory
– 512 Bytes EEPROM
– 1 Kbyte Internal SRAM
– Write/Erase Cycles: 10,000 Flash/100,000 EEPROM
– Data retention: 20 years at 85°C/100 years at 25°C(1)
– Optional Boot Code Section with Independent Lock Bits
In-System Programming by On-chip Boot Program
True Read-While-Write Operation
– Programming Lock for Software Security
• JTAG (IEEE std. 1149.1 Compliant) Interface

9
– Boundary-scan Capabilities According to the JTAG Standard
– Extensive On-chip Debug Support
– Programming of Flash, EEPROM, Fuses, and Lock Bits through the JTAG Interface
• Peripheral Features
– Two 8-bit Timer/Counters with Separate Prescalers and Compare Modes
– One 16-bit Timer/Counter with Separate Prescaler, Compare Mode, and Capture
Mode
– Real Time Counter with Separate Oscillator
– Four PWM Channels
– 8-channel, 10-bit ADC
8 Single-ended Channels
7 Differential Channels in TQFP Package Only
2 Differential Channels with Programmable Gain at 1x, 10x, or 200x
– Byte-oriented Two-wire Serial Interface
– Programmable Serial USART
– Master/Slave SPI Serial Interface
– Programmable Watchdog Timer with Separate On-chip Oscillator
– On-chip Analog Comparator
• Special Microcontroller Features
– Power-on Reset and Programmable Brown-out Detection
– Internal Calibrated RC Oscillator
– External and Internal Interrupt Sources
– Six Sleep Modes: Idle, ADC Noise Reduction, Power-save, Power-down, Standby
and Extended Standby
• I/O and Packages
– 32 Programmable I/O Lines
– 40-pin PDIP, 44-lead TQFP, and 44-pad QFN/MLF
• Operating Voltages
– 2.7V - 5.5V for ATmega16L
– 4.5V - 5.5V for ATmega16

10
• Speed Grades
– 0 - 8 MHz for ATmega16L
– 0 - 16 MHz for ATmega16
• Power Consumption @ 1 MHz, 3V, and 25°C for ATmega16L
– Active: 1.1 mA
– Idle Mode: 0.35 mA
– Power-down Mode: < 1 μA
The AVR core combines a rich instruction set with 32 general purpose working registers. All the
32 registers are directly connected to the Arithmetic Logic Unit (ALU), allowing two independent
registers to be accessed in one single instruction executed in one clock cycle. The resulting
architecture is more code efficient while achieving throughputs up to ten times faster than
conventional CISC microcontrollers.
The ATmega16 provides the following features: 16 Kbytes of In-System Programmable Flash
Program memory with Read-While-Write capabilities, 512 bytes EEPROM, 1 Kbyte SRAM, 32

11
general purpose I/O lines, 32 general purpose working registers, a JTAG interface for
Boundaryscan,
On-chip Debugging support and programming, three flexible Timer/Counters with compare
modes, Internal and External Interrupts, a serial programmable USART, a byte oriente
Two-wire Serial Interface, an 8-channel, 10-bit ADC with optional differential input stage with
programmable gain (TQFP package only), a programmable Watchdog Timer with Internal
Oscillator,
an SPI serial port, and six software selectable power saving modes. The Idle mode stops the CPU
while allowing the USART, Two-wire interface, A/D Converter, SRAM, Timer/Counters, SPI
port, and interrupt system to continue functioning. The Power-down mode saves the register
contents but freezes the Oscillator, disabling all other chip functions until the next External
Interrupt or Hardware Reset. In Power-save mode, the Asynchronous Timer continues to run,
allowing the user to maintain a timer base while the rest of the device is sleeping. The ADC Noise
Reduction mode stops the CPU and all I/O modules except Asynchronous Timer and ADC, to
minimize switching noise during ADC conversions. In Standby mode, the crystal/resonator
Oscillator is running while the rest of the device is sleeping. This allows very fast start-up
combined with low-power consumption. In Extended Standby mode, both the main Oscillator and
the Asynchronous Timer continue to run. The device is manufactured using Atmel‟s high density
nonvolatile memory technology. The Onchip ISP Flash allows the program memory to be
reprogrammed in-system through an SPI serial interface, by a conventional nonvolatile memory
programmer, or by an On-chip Boot program running on the AVR core. The boot program can use
any interface to download the applicationprogram in the Application Flash memory. Software in
the Boot Flash section will continue to run while the Application Flash section is updated,
providing true Read-While-Write operation. By combining an 8-bit RISC CPU with In-System
Self-Programmable Flash on a monolithic chip, the Atmel ATmega16 is a powerful
microcontroller that provides a highly-flexible and cost-effective solution to many embedded
control applications. The ATmega16 AVR is supported with a full suite of program and system
development tools including: C compilers, macro assemblers, program debugger/simulators, in-
circuit emulators, and evaluation kits.
Pin Descriptions
 VCC Digital supply voltage.
 GND Ground.
 Port A (PA7..PA0) Port A serves as the analog inputs to the A/D Converter.
Port A also serves as an 8-bit bi-directional I/O port, if the A/D Converter is not used.
Port pins

12
can provide internal pull-up resistors (selected for each bit). The Port A output buffers
have symmetrical drive characteristics with both high sink and source capability. When
pins PA0 to PA7
are used as inputs and are externally pulled low, they will source current if the internal
pull-up
resistors are activated. The Port A pins are tri-stated when a reset condition becomes
active,
even if the clock is not running.
 Port B (PB7..PB0) Port B is an 8-bit bi-directional I/O port with internal pull-up resistors
(selected for each bit). The Port B output buffers have symmetrical drive characteristics
with both high sink and source
capability. As inputs, Port B pins that are externally pulled low will source current if the
pull-up
resistors are activated. The Port B pins are tri-stated when a reset condition becomes
active,
even if the clock is not running.
 Port C (PC7..PC0) Port C is an 8-bit bi-directional I/O port with internal pull-up resistors
(selected for each bit). The Port C output buffers have symmetrical drive characteristics
capability. As inputs, Port C pins that are externally pulled low will source current if the
pull-up
resistors are activated. The Port C pins are tri-stated when a reset condition becomes
active,
even if the clock is not running. If the JTAG interface is enabled, the pull-up resistors on
pins
PC5(TDI), PC3(TMS) and PC2(TCK) will be activated even if a reset occurs.
 Port D (PD7..PD0) Port D is an 8-bit bi-directional I/O port with internal pull-up resistors
(selected for each bit). ThePort D output buffers have symmetrical drive characteristics
capability. As inputs, Port D pins that are externally pulled low will source current if the
pull-up
resistors are activated. The Port D pins are tri-stated when a reset condition becomes
active,
even if the clock is not running. Port D also serves the functions

13
 RESET Reset Input. A low level on this pin for longer than the minimum pulse length will
generate a
reset, even if the clock is not running.
 XTAL1 Input to the inverting Oscillator amplifier and input to the internal clock operating
circuit.
 XTAL2 Output from the inverting Oscillator amplifier.
 AVCC AVCC is the supply voltage pin for Port A and the A/D Converter. It should be
externally connected
to VCC, even if the ADC is not used. If the ADC is used, it should be connected to VCC
through a low-pass filter.
 AREF AREF is the analog reference pin for the A/D Converter
Dual H-Bridge Motor Driver L293D IC: The L293 and L293D are quadruple high-
current half-H drivers. The L293 is designed to provide bidirectional drive currents of up to 1 A at
voltages from 4.5 V to 36 V. The L293D is designed to provide bidirectional drive currents of up
to 600-mA at voltages from 4.5 V to 36 V. Both devices are designed to drive inductive loads such
as relays, solenoids, dc and bipolar stepping motors, as well as other high-current/high-voltage
loads in positive-supply applications. All inputs are TTL compatible. Each output is a complete
totem-pole drive circuit, with a Darlington transistor sink and a pseudo-Darlington source. Drivers
are enabled in pairs, with drivers 1 and 2 enabled by 1,2EN and drivers 3 and 4 enabled by 3,4EN.
When an enable input is high, the associated drivers are enabled, and their outputs are active and
in phase with their inputs. When the enable input is low, those drivers are disabled, and their
outputs are off and in the high-impedance state. With the proper data inputs, each pair of drivers
forms a full-H (or bridge) reversible drive suitable for solenoid or motor applications.
Motor driver is basically a current amplifier which receives a low-current signal from the
microcontroller and gives out higher current signal which can control and drive a motor. To turn
ON and off a motor and to run it in single direction one switch is enough, but if we want to change
the direction than we need to change the polarity. This can be done by using H-bridge circuit.
Turning the switches A,B,C and D we can run the motor in any direction. L293d IC is a 16 pin
DIP. This driver IC can simultaneously control two small motors in either direction, forward and
reverse with just 4 microcontroller pins.

14
_ Featuring Unitrode L293 and L293D
Products Now From Texas Instruments
_ Wide Supply-Voltage Range: 4.5 V to 36 V
_ Separate Input-Logic Supply
_ Internal ESD Protection
_ Thermal Shutdown
_ High-Noise-Immunity Inputs
_ Functionally Similar to SGS L293 and SGS L293D
_ Output Current 1 A Per Channel (600 mA for L293D)
_ Peak Output Current 2 A Per Channel (1.2 A for L293D)
_ Output Clamp Diodes for Inductive Transient Suppression (L293D)
Pin diagram of L293D

15
Pin 1 Pin 2 Pin 7 Function
High High Low Anti clockwise
High Low High Clockwise
High High High Stop
High Low Low Stop
Low X X Stop

16
Voltage Regulator
For most electronic equipment a DC power supply is generally preferred since, except for a start-
up transient, the supply ideally does not introduce any fiduciary timing dependence. However by
and large electrical power is generated and distributed with a sinusoidal waveform. Thus a power
supply typically begins with a rectifier to convert a sinusoidal input, e.g. 60 Hz for most U.S.
consumer electronics, to a rectified waveform. The supply is almost always a voltage supply as a
practical matter; it is generally easier and less lossy to maintain a voltage supply rather than a
current supply in a standby condition, and to operate it under varying load. The unidirectional but
varying rectified waveform is filtered in various ways to reduce the variation (the ripple' voltage)
to an acceptable level. Nevertheless for many purposes even the filtered supply voltage ripple
variation often is unacceptably large, particularly within practical filtering limitations. Power line
variations, for example, are passed on to the rectified output. Moreover the Thevenin equivalent
circuit for the rectified and filtered power supply often involves a substantial 'internal' resistance,
so that the terminal voltage of the supply varies with the amount of current drawn because of the
voltage drop across this internal resistance. A 'voltage regulator' inserts additional electronics
between the rectifier terminals and the load primarily to reduce this terminal voltage variation, but
also to provide other associated benefits.
There are broadly two types of electronic voltage regulator circuits
 linear voltage regulators
 switching

17
Capacitors
Capacitors are one of the most useful components in electronics, and after resistors are the most
numerous components in circuits. Capacitors (and inductors) have the ability to store electrical
energy, inductors store energy as a magnetic field around the component, but the capacitor stores
electrical energy directly, as an ELECTROSTATIC FIELD created between two metal "plates
Basic Circuit Symbols for Capacitors Fig shows the UK and US circuit symbols for a variety of
capacitor types. A basic fixed value type of capacitor consists of two plates made from metallic
foil, separated by an insulator. This may be made from a choice of different insulating materials,
having good DIELECTRIC properties.

18
Capacitor types
• High Voltage Electrolytic used in power supplies.
• Axial Electrolytic; lower voltage smaller size for general purpose where large capacitance
values are needed.
• High Voltage disk ceramic; small size and capacitance value, excellent tolerance
characteristics.
• Metalised Polypropylene; small size for values up to around 2μF good reliability.
• Sub miniature Multi layer ceramic chip (surface mount) capacitor. Relatively high
capacitance for size achieved by multiple layers, effectively several capacitors in parallel.
Electrolytic Capacitors
The construction of electrolytic capacitors is similar in some ways to a rolled foil capacitor.
Except that the layers between the foil are now two very thin layers of paper, one that forms an
insulator separating the rolled pairs of layers and the other, a layer of tissue between the foil
plates, soaked in an electrolyte that makes the tissue conductive!
It would seem from the previous paragraph that the soaked tissue places a short circuit between
the plates. But the real dielectric layer is created after construction is complete, in a process called
"Forming". A current is passed through the capacitor, and the action of the electrolyte causes a
very thin layer of aluminium oxide to build up on the positive plate. It is this layer that is used as
the insulating dielectric. The capacitor therefore has a very thin and efficient dielectric, giving

19
capacitance values many hundreds times greater than is possible with a conventional plastic film
capacitor of a similar physical size.
The down side with this process is that the capacitor is polarised and must not have reversed
polarity voltages applied. If this occurs the insulating oxide layer is stripped away again and the
capacitor may pass a large current. As this occurs in a sealed container, the "liquid" electrolyte
quickly boils and expands rapidly. This can lead to an explosion within seconds! NEVER connect
an electrolytic capacitor the wrong way round!
Analog to Digital Converter (ADC)
Analog-to-digital converters (ADCs) translate analog quantities, which are characteristic of most
phenomena in the "real world," to digital language, used in information processing, computing,
data transmission, and control systems. Digital-toanalog converters (DACs) are used in
transforming transmitted or stored data, or the results of digital processing, back to "real-world"
variables for control, information
display, or further analog processing.
Analog input variables, whatever their origin, are most frequently converted by transducers into
voltages or currents. These electrical quantities may appear as fast or slow "dc" continuous direct
measurements of a phenomenon in the time domain, as modulated ac waveforms (using a wide
variety of modulation techniques), or in some combination, with a spatial configuration of related
variables to represent shaft angles.
Most of the physical quantities around us are continuous. By continuous we mean that the quantity
can take any value between two extreme. If an electrical quantity is made to vary directly in
proportion to the physical quantity (that needs to be measured) then what we have is an analog
signal. Now we have we have brought a physical quantity into electrical domain. The electrical
quantity in most case is voltage. To bring this quantity into digital domain we have to convert this
into digital form.
For this an ADC or analog to digital converter is used. ATmega16 has an ADC on chip. An ADC
converts an input voltage into a number. An ADC has a resolution of 10bits. A 10 Bit ADC has a
range of 0-1023. (2^10=1024) The ADC also has a Reference voltage (ARef). When input voltage
is GND the output is 0 and when input voltage is equal to ARef the output is 1023. So the input
range is 0-ARef and digital output is 0-1023.
We are using ADC in our project to acquire data from the 2 -axis accelerometer which provides us
with an analog voltage signal to convert this signal into digital domain for further processing. This
needs to be done because the ATmega16 microcontroller can only work in digital domain.

20
LCD
LCDs use voltage-sensitive organic molecules with a helical structure that either block or permit
the passage of polarized light. Areas filled with molecules that form parts of the display are called
segments or pixels. For proper function, alternating current (AC) has to be applied to the
segments.
LCDs with only a few segments can be operated in static mode, i.e. each segment has its own wire
or pin that is connected to an AC voltage source (driver). In order to keep the number of
connections low, LCDs with medium or large density are usually operated in multiplexed mode,
i.e. individual segments share pins with others, and the display is driven by selecting one group of
segments for a brief period of time and then moving on to the next group. The inertia of the
organic molecules in a segment keeps the segment “ON” while the driver is accessing another
group of segments.
Depending on their operation mode, LCDs are usually categorized as:
• Static Drive: LCD Glass or LCD Modules with a simple segment displays are the only parts that
have an option of Static Drive. The Static Drive configuration means that there is an individual
control line to select each LCD segment and there is only a single common line that connects to
them all. This configuration produces the best display with the widest temperature range, but it
requires more interconnections that a multiplexed display would require.

21
• Multiplexed Drive: The Multiplexed Drive configuration means that each control line selects
several LCD segments and that the final selection is made by selecting the correct common signal
that also connects to several LCD segments. This configuration uses fewer interconnections which
is cost effective for smaller displays. This configuration degrades the temperature and image
performance slightly.
In 1968, RCA Laboratories developed the first liquid crystal display (LCD). Since then, LCD‟s
have been implemented on almost all types of digital devices, from watches to computer to
projection TVs .LCD‟s operate as a light “valve”, blocking light or allowing it to pass through. An
image in an LCD is formed by applying an electric field to alter the chemical properties of each
LCC (Liquid Crystal Cell) in the display in order to change a pixel‟s light absorption properties.
These LCC‟s modify the image produced by the backlight into the screen output requested by the
controller. Through the end output may be in color, the LCC‟s are monochrome, and the color is
added later through a filtering process. Modern laptop computer displays can produce 65,536
simultaneous colors at resolution of 800 X 600.
LCD Modules can present textual information to user. They come in various types. The most
popular one that we use here can display 2 lines of 16 characters.
LCD on ATmega16 Development is being used to display the value of the ADC output which
takes the accelerometer as the input .
An array of Liquid Crystal segments
 When not in an electrical field, crystals are organized in a random pattern
 When an electric field is applied, the crystals align to the field
 The crystals themselves do not emit light, but „gate‟ the amount of light that can pass
through them
Crystals aligned perpendicular to a light source will prevent light from passing through them
Each LCD segment is aligned with an electric field A light source (backlight) is needed to drive
light through the aligned crystal field.
Passive LCD panels
 Consists of a grid of row and columns electrical signals
 Columns and rows connect perpendicularly to every segment in the LCD
 Columns and rows are multiplexed to many different segments
 An IC controls which column and row are selected to enable or disable the segment at the
row/column intersection
 A small bias is applied to the row and column to generate a field at the intersection
 No charge is stored at the segment
 It may take multiple passes to correctly align the field to the desired val

22
Active LCD panels
 Consists of a grid of row and columns electrical signals
 Columns and rows connect perpendicularly to a active device (transistor) for every
segment in the LCD
 Columns and rows are multiplexed to many different segments
 An IC controls which column and row are selected to enable or disable the segment at the
row/column intersection
 The selected row and column enable the transistor
 Charge is stored at the transistor
 One pass will set the aligned state of the transistor (although it may still take a little time
for all the crystals to align)
 A stronger backlight is needed than a passive display
RESISTORS
To oppose the flow of electrons ( current). The symbols are shown below.Resistance is measured
in units called “Ohm”. 1000 ohms is shownas 1k ohm (103ohm) and 1000 k ohm is shown as
M.ohms (106ohm).
Resistors can be broadly of two types.
•Fixed Resistors and Variable Resistors
Carbon Film (5%, 10% tolerance) and Metal Film Resistors (1%,2% tolerances) and wire wound
resistors. A fixed resistor is one for which the value of its resistance is specified and cannot be
varied in general.
Resistance Value: The resistance value is displayed using the color code ( the colored bars/the
colored stripes ), because the average resistor is too small to have the value printed on it with
numbers. The resistance value is a discrete value.
RESISTORS
Example 2:(Yellow=4),(Violet=7),(Black=0),(Red=2) 470 x 102= 47k ohm ;Tolerance(Brown) =
±1% Tolerance of the resistor is also an important property to consider. A 100 Ωresistor with 10%
tolerance, means that its value can be any fixed value between 90 to 110 ohms. A 120 Ωresistor
with 10% tolerance, means that its value can be any fixed value between 108 to 132 ohms. Thus
the upper tolerance limit (110) of the lower value (100) and the lower tolerance limit (108) of the
upper value (120) overlap.Hence a resistor with value between 100 to 120 ohms can be obtained
from either of the two sets of 100 or 120 ohms. Similarly a resistor with value between 120 to 150

23
ohms can be obtained from either of the two sets of 120 or 150 ohms. Resistor values for
manufacturing under 10% tolerance are chosen such that the upper limit of the lower value and the
lower limit of the upper value overlap.
Carbon film resistors: This is the most general purpose, cheap resistor. Usually the tolerance of
the resistance value is ±5%. Power ratings of 1/8W, 1/4W and 1/2W are frequently used. The
disadvantage of using carbon film resistors is that they tend to be electrically noisy.
Metal film resistors: Metal film resistors are used when a higher tolerance (more accurate value)
is needed. Nichrome(Ni-Cr) is generally used for the material of resistor. They are much more
accurate in value than carbon film resistors. They have about ±0.05% tolerance.

24
OTHER RESISTORS: There is another type of resistor called the wire wound resistor. A wire
wound resistor is made of metal resistance wire, and because of this, they can be manufactured to
precise values. Also, high-wattage resistors can be made by using a thick wire material. Wire
wound resistors cannot be used for high-frequency circuits.
Ceramic Resistor: Another type of resistor is the Ceramic resistor. These are wire wound
resistors in a ceramic case, strengthened with a special cement. They have very high power
ratings, from 1 or 2 watts to dozens of watts. These resistors can become extremely hot when used
for high power applications, and this must be taken into account when designing the circuit.
Single in line network resistor: It is made with many resistors of the same value, all inone
package. One side of each resistor is connected with one side of all the other resistors inside. One
example of its use would be to control the current in a circuit powering many light emitting diodes
(LEDs). The face value of the resistance is printed. In the photograph below, 8 resistors are housed
in the package. Each of the leads on the package is one resistor. The ninth lead on the left side is
the common lead.
4S resistor network: The 4S indicates that the package contains 4 independentresistors that are
not wired together inside. The housing has eight leads instead of nine.
Variable resistors: There are two general ways in which variable resistors are used.One is the
variable resistor whose value is easily changed, like the volume adjustment of Radio. The other is
semi-fixed resistor that is not meant to be adjusted by anyone but a technician. It is used to adjust
the operating condition of the circuit by the technician.Semi-fixed resistors are used to compensate
for the inaccuracies of the resistors, and to fine-tune a circuit. The rotation angle of the variable
resistor is usually about 300 degrees. Some variable resistors must be turned many times( multi-
turn Pot) to use the whole range of resistance they offer. This allows for very precise adjustments
of their value.These are called "Potentiometers" or "Trimmer Potentiometers” or “presets”. The
four resistors at the center are the semi-fixed type. The two resistors on the left are the trimmer
potentiometers

25
Accelerometer sensor: ADXL 335
GENERAL DESCRIPTION
The ADXL335 is a small, thin, low power, complete 3-axis accel-erometer with signal
conditioned voltage outputs. The product measures acceleration with a minimum full-scale range
of ±3 g. It can measure the static acceleration of gravity in tilt-sensing applications, as well as
dynamic acceleration resulting from motion, shock, or vibration.
The user selects the bandwidth of the accelerometer using the CX, CY, and CZ capacitors at the
XOUT, YOUT, and ZOUT pins. Bandwidths can be selected to suit the application, with a range
of 0.5 Hz to 1600 Hz for the X and Y axes, and a range of 0.5 Hz to 550 Hz for the Z axis.
The ADXL335 is available in a small, low profile, 4 mm × 4 mm × 1.45 mm,
Functional block diagram

26
FEATURES
 3-axis sensing
 Small, low profile package
 4 mm × 4 mm × 1.45 mm LFCSP
 Low power : 350 μA (typical)
 Single-supply operation: 1.8 V to 3.6 V
 10,000 g shock survival
 Excellent temperature stability
 BW adjustment with a single capacitor per axis
 RoHS/WEEE lead-free compliant
APPLICATIONS
 Cost sensitive, low power, motion- and tilt-sensing applications
 Mobile devices
 Gaming systems
 Disk drive protection
 Image stabilization
 Sports and health devices

27
Pin configuration

28
ACCELEROMETER
An accelerometer is a sensing element that measures acceleration; acceleration is the rate of
change of velocity with respect to time. It is a vector that has magnitude and
direction.Accelerometers measure in units of g – a g is the acceleration measurement for gravity
which is equal to 9.81m/s². Accelerometers have developed from a simple water tube with an air
bubble that showed the direction of the acceleration to an integrated circuit that can be placed on a
circuit board. Accelerometers can measure: vibrations, shocks, tilt, impacts and motion of an
object.
Types of Accelerometers
There are a number of types of accelerometers
 Capacitive: accelerometers sense a change in electrical capacitance, with respect to
acceleration. The accelerometer senses the capacitance change between a static condition
and the dynamic state.
 Piezoelectric: accelerometers use materials such as crystals, which generate electric
potential from an applied stress. This is known as the piezoelectric effect. As stress is
applied, such as acceleration, an electrical charge is created.
 Piezoresistive: accelerometers (strain gauge accelerometers) work by measuring the
electricalresistance of a material when mechanical stress is applied .
 Hall Effect: accelerometers measure voltage variations stemming from a change in the
magnetic
field around the accelerometer.
 Magnetoresistive: accelerometers work by measuring changes in resistance due to a
magnetic field. The structure and function is similar to a Hall Effect accelerometer except
that instead ofmeasuring voltage, the magnetoresistive accelerometer measures resistance.
 Heat transfer: accelerometers measure internal changes in heat transfer due to
acceleration. A single heat source is centered in a substrate and suspended across a cavity.
Thermoresistors are spaced equally on all four sides of the suspended heat source. Under
zero acceleration the heat gradient will be symmetrical. Acceleration in any direction
causes the heat gradient to becomeasymmetrical due to convection heat transfer.
 MEMS-Based Accelerometers : MEMS (Micro-Electro Mechanical System) technology
is based on a number of tools and methodologies, which are used to form small structures
with dimensions in the micrometer scale
 (one millionth of a meter). This technology is now being utilized to manufacture state of
the art MEMS-Based Accelerometers.

29
 Future Accelerometer Advancements
In the next decade, NANO technology will create new applications and dramatically
reshape this area of technology.
Applications for Accelerometer
From industry to education, accelerometers have numerous applications. These applications range
from triggering airbag deployments to the monitoring of nuclear reactors. There are a number of
practical applications for accelerometers; accelerometers are used to measure static acceleration
(gravity), tilt of an object, dynamic acceleration, shock to an object, velocity, orientation and the
vibration of an object. Accelerometers are becoming more and more ubiquitous: cell phones,
computers and washing machines now contain accelerometers.
Other practical applications include:
• Measuring the performance of an automobile
• Measuring the vibration of a machine
• Measuring the motions of a bridge
• Measuring how a package has been handled
Selecting an Accelerometer
When selecting an accelerometer for an application the first factors to consider are:
1. Dynamic Range: Dynamic range is the +/- maximum amplitude that the accelerometer can
measure before distorting or clipping the output signal. Dynamic range is typically specified in g's
2. Sensitivity: Sensitivity is the scale factor of a sensor or system, measured in terms of change in
output signal per change in input measured. Sensitivity references the accelerometer‟s ability to
detect motion. Accelerometer sensitivity is typically specified in millivolt per (mV/g).
3. Frequency response: Frequency response is the frequency range for which the sensor will
detect motion and report a true output. Frequency response is typically specified as a range
measured in Hertz (Hz).
4. Sensitive axis: Accelerometers are designed to detect inputs in reference to an axis; single-axis
accelerometers can only detect inputs along one plane. Tri-axis accelerometers can detect inputs in
any plane and are required for most applications.

30
5. Size and Mass: Size and mass of an accelerometer can change the characteristics of the object
being tested. The mass of the accelerometers should be significantly smaller than the mass of the
system to be monitored.
Acceleration Recorders
An accelerometer by itself is only a sensing element, in order for it to be useful the sensor needs to
be combined with other elements such as, power, logic, memory and a means to translate the
output. An acceleration recorder incorporates all of these elements into one package. One example
of an acceleration recorder is the GP series designed by Sensr. They are rugged, compact
instruments for recording motion, shock, impact, orientation and temperature. The instruments
have been specifically designed to be user-friendly. The GP series data loggers feature: real-time
data streaming, a USB interface, easy-to-use software, LED alert indicators, event flagging and a
tri-axial MEMS-based accelerometers.
Accelerometer sensors measure the acceleration experienced by the sensor and anything to which
the sensor is directly attached. Accelerometer sensors have many applications. The most common
commercial application is impact sensors for triggering airbag deployment in automobiles: when
the acceleration exceeds 30 to 50 g‟s,† an accident is assumed and the airbaggd deploy. Such
sensors are designed to be rugged and reliable, and are made in high volume and at low cost by
several chip manufacturers.Airbag sensors don‟t need to be very accurate: with a threshold of 50
g‟s, an accuracy of 1 to 2 g is acceptable. High precision accelerometer sensors have a variety of
applications. They are used with gyroscopes (which can also be microfabricated using MEMS) in
inertial guidance mechanisms.
the displacement is calculated by twice integrating the acceleration signal, and the gyroscopes
indicate the direction of displacement. Such components are used to make small inertial guidance
units10 in rockets and aircraft, which complement direct navigation using satellite global
positioning.
When working with accelerometers in the earth‟s gravitational field, there is always the
acceleration due to gravity. Thus the signal from an accelerometer sensor can be separated into
two signals: the acceleration from gravity, and external acceleration. The acceleration from gravity
allows measurement of the tilt of the sensor by identifying which direction is “down”. By filtering
out the external acceleration, the orientation of a three-axis sensor can be calculated from the
accelerations on the three accelerometer axes. Orientation sensing can be very useful in
navigation.
Ultra-high precision but low bandwidth accelerometer sensors have applications in seismology.
Two important seismology applications are detecting earthquakes and geophysical mapping
(particularly for petroleum exploration). Geophysical accelerations are low frequency (<50 Hz)
but require extremely high sensitivity-- errors less then 1 μg. An accelerometer being developed at

31
NASA‟s Jet Propulsion Laboratory (Pasadena, CA) for applications in seismology has a
sensitivity of 1 ng/Hz1/2 with a bandwidth of 0.05 to 50 Hz, for a total noise level of 7 ng.
Accelerometer sensors can also be used to indirectly infer the status of a machine. The range of
acceleration is a few g‟s, and the precision required is mg‟s, with a bandwidth up to the frequency
of rotation. By fixing a two-axis accelerometer (the axes perpendicular to the axis of rotation), an
out-of-balance load is detected by excessive vibration.
(† One g is the acceleration due to gravity, 9.8 m/s2)
The goal of this project is to measure the two-dimensional acceleration of human hand motion
with adequate accuracy and precision, the necessary bandwidth for normal human motion, and the
amplitude range required for the highest normal accelerations. At the same time, the physical
presence of the sensor should not alter the hand motion. The application of measuring something
sensitive to external mass like the human hand requires the accelerometer sensor to be extremely
small and lightweight
Basic Theory of Operation
Accelerometer sensors convert either linear or angular acceleration to an output signal.
Accelerometer sensors use Newton’s second law of motion,
F= ma by measuring the force from acceleration on an object whose mass is known. There are
many ways to measure the force exerted on the mass, called a proof mass, but the most common
method used in accelerometer sensors is measuring the displacement of the mass when it is
suspended by springs. The massspring system is shown in diagram
Forces acting on the proof mass include the force from external acceleration, the force from
damping (proportional to velocity), and the restorative force of the spring (proportional to
position).

32
In accelerometer sensors operating far from the resonant frequency of the mass-spring system, the
effect of damping can be largely ignored. Some high precision accelerometer sensors operate near
the resonant frequency to mechanically amplify the displacement from acceleration.
For example, the JPL seismic accelerometer is designed to have the resonant frequency at 10 to 25
Hz, and the bandwidth (operating range) of the sensor is 0.05 to 50Hz. Furthermore, in the JPL
sensor the cavity around the proof mass is evacuated to reduce the damping coefficient as much as
possible, increasing the mechanical amplification. However, all sensors discussed hereafter are
operating far from their resonant frequency
For sufficiently small displacements, the spring constant K(x) can be assumed to be constant.
In equilibrium when the mass is not moving, the restorative force exerted by the spring is equal to
the force from acceleration on the proof mass. The displacement of the spring, x, is a parameter
that can be converted to an electrical signal by a variety of methods. The two common methods
are measuring a change in
resistance of a piezoresistive material and measuring a change in capacitance between moving and
fixed electrical elements. An alternative way of directly measuring the acceleration force exerted
on the proof mass is measuring a change in the charge of a piezoelectric material.
MTL Accelerometer Linearity Analysis and Specification Calculations
The electronics that convert the differential capacitance signal in the sensor results in an analog
voltage that is linearly proportional to the proof mass position in the sensor. This is very
convenient because the proof mass position is linearly proportional to external acceleration and
thus the analog voltage will be linear with acceleration. Consequently an important aspect of

33
analyzing the sensor is considering how linear the output is withacceleration. This section
investigates the proportionality between the proof mass position and
external acceleration..
Analyzing linearity of the physical mass-spring system is equivalent to asking how strongly the
spring constant K(x) is a function of the mass displacement x. Accurate estimates of the
restorative force of the spring can be made using numerical techniques such as finite element
analysis or solving analytical equations. One analytical method commonly used is minimization of
energy in the system. The derivation of the force necessary for beam deflection (applicable to the
tethers that hold the mass in place) is described elsewhere, and only the result of the calculation
are presented here.
The restorative force at the end of a long deflecting beam is given in Equation E is
Young‟s modulus for the material (silicon: E = 1.525 x 1011 N/m2), d is the deflection, and D is
the depth, L is the length, and W is the width of the beam (width is in the direction of
displacement). The first term of the summation is linear with displacement; this term represents
the ideal spring constant K, associated with beam bending. The second term is nonlinear with
displacement and is associated with stretching the beam.
At each of the four corners of the mass are tethers, consisting of two beams in series. (The
two beams act as springs in series, which add like capacitors in series.)
Accelerometer ADXL 335 sensor move in right for right direction

34
Accelerometer ADXL 335 move in left for left direction

35
CIRCUIT DIAGRAM
DEVELOPMENT PHASE
Our proposed hardware system involves following steps-
Step 1: After detecting gesture command analog signal of accelerometer is send to the Atmega16
microcontroller.
Step 2: As soon as the Analog signal is obtained by the microcontroller it is converted into the
Digital signal.
.Step 3: L293D motor driver circuit takes digital signal as an input from the microcontroller and
gives digital output to the DC motors of the robot.
Step 4: LCD display different coordinate of X-Y axis on the basis of different gesture of the hand
.

36
PROGRAMMING USED IN HARDWARE
#define F_CPU 12000000UL
#include <avr/io.h>
#include "lcd.h" //include LCD Library
#include "lcd.c"
#include <util/delay.h>
void InitADC(void)
{
ADMUX|=(1<<REFS0)|(1<<REFS1);
ADCSRA|=(1<<ADEN)|(1<<ADPS0)|(1<<ADPS1)|(1<<ADPS2); //ENABLE ADC, PRESCALER
128
}
uint16_t readadc(uint8_t ch)
{
ch&=0b00000111; //ANDing to limit input to 7
ADMUX = (ADMUX & 0xf8)|ch; //Clear last 3 bits of ADMUX, OR with ch
ADCSRA|=(1<<ADSC); //START CONVERSION
while((ADCSRA)&(1<<ADSC)); //WAIT UNTIL CONVERSION IS COMPLETE
return(ADC); //RETURN ADC VALUE

37
}
int main(void)
{
char a[20], b[20], c[20];
uint16_t x,y,z;
DDRB=0xFF;
DDRA=0x00;
InitADC(); //INITIALIZE ADC
lcd_init(LCD_DISP_ON); //INITIALIZE LCD
lcd_clrscr( );
int range=70
lcd_puts("PROJECT ON ");
_delay_ms(1000);
lcd_command(0x01);
lcd_puts("HAND GESTURE ");
_delay_ms(1000);
lcd_command(0x01);
lcd_puts("CONTROLLED ROBOT ");
_delay_ms(1000);
lcd_command(0x01);

38
lcd_puts("BY------> ");
_delay_ms(1000);
lcd_command(0x01);
lcd_puts("PUSHPA ");
_delay_ms(1000);
lcd_command(0x01);
lcd_puts("ALKA ");
_delay_ms(1000);
lcd_command(0x01);
lcd_puts("SUBMITTED TO->");
_delay_ms(1000);
lcd_command(0x01);
lcd_puts("Mr. VINAY NEGI");
_delay_ms(1000);
lcd_command(0x01);
while(1)
{
lcd_home();
x=readadc(0); //READ ADC VALUE FROM PA.0
y=readadc(1); //READ ADC VALUE FROM PA.1
///// z=readadc(2); //READ ADC VALUE FROM PA.2

39
//////////_delay_ms(300);
itoa(x,a,10);
itoa(y,b,10);
itoa(z,c,10);
lcd_puts("x="); //DISPLAY THE RESULTS ON LCD
lcd_gotoxy(2,0);
lcd_puts(a);
lcd_gotoxy(7,0);
lcd_puts("y=");
lcd_gotoxy(9,0);
lcd_puts(b);
//// lcd_gotoxy(0,1);
/////lcd_puts("z=");
////////lcd_gotoxy(2,1);
///////// lcd_puts(c);
if((x>580-range && x <640+range ) && (y>600-range && y <640+range ))
{
PORTB=0b00000000;
}

40
{
PORTB=0b00001001;
}
{
PORTB=0b00000110;
}
{
PORTB=0b00000001;
}
{
PORTB=0b00001000;
}
}
}

41
Software Design
The software is designed to achieve the required objective. There are different software modules
which make up the project are:
 Hand motion with accelerometer on the top of the hand.
 Conversion of Analog signal of accelerometer into Digital signal in Atmega16 which is
done by Analog to Digital converter in Atmega16.
 Different coordinate of the accelerometer is converted into digital signal as a command for
Atmega16 which in turn drive L293D motor drive in particular direction according to the
hand gesture .
 LCD display different X-Y coordinate on the basis of hand movement.

42
RECEIVER CAPTURING GESTURES USING ACCELEROMETER
An accelerometer is a device that measures proper acceleration. The proper acceleration measured
by an accelerometer is not necessarily the coordinate acceleration (rate of change of velocity).
Instead, the accelerometer sees the acceleration associated with the phenomenonof weight
experienced by any test mass at rest in the frame of reference of the accelerometer device.
For example, an accelerometer at rest on the surface of the earth will measure an acceleration g=
9.81 m/s2 straight upwards, due to its weight. By contrast, accelerometers in free fall or at rest in
outer space will measure zero. Another term for the type of acceleration that accelerometers can
measure is gforce acceleration .
The Accelerometer We used is multi axis And Analog Device. It Gives 3 Dimensional Data in
Analog Form We convert this Analog Data Into Digital Form. The 3-Dimensional Coordinates
values are used to differentiate between different Gestures.The variations in hand movements
results changes in 3 D coordinate system. We can further gather these Changes and process in
Processor to recognize the different Gestures by hand. The Data from accelerometer is ranges
from 46 To 126.This range of values depends on prescalar value used in converting Analog to
Digital Conversion. The Range of values Of X,Y Axis
.
CONVERTING ACCELERATIONS

43
Fig. 5 shows the axis orientation of the MMA7260QT. The positive signs along x-, y-, and z-axis
(with arrows indicated) define the direction that the sensor is accelerated to. The outputs from the
MMA7260QT are analog signals with maximal bandwidth response of 350Hz (x- and y-axis) and
150Hz (z-axis). For any axis with no applied acceleration, its output is equal to half the supply
voltage (VDD). The output voltage increases from the half VDD level when the sensor is
accelerated in the positive direction along its sensitive axis. On the contrary, the signal output is
below the half VDD level when the sensor is accelerated in negative direction (or decelerated)
along its sensitive axis.
For a typical VDD=3.3V application, the zero-acceleration output is 0.5×3.3=1.65V. When the
sensor is accelerated, the outputs of the sensitive axes deviate from 1.65V and the variation is
according to the selected sensitivity S (mV/g, voltage per gravity) as shown in Table I For
example, if 2g sensitivity is selected, its sensitivity is 600mV/g (g is gravity in the amount of
9.81m/s2) and the voltage within the sensitivity range changes linearly with the measured
acceleration (Acc).
Sensitivity can be selected with 2 logic inputs connected to pin g-Select 1 and g-Select 2. The
sensitivity can be changed at anytime during operation. The g-select pins of the
MMA7260QT can be configured with high (1) or low (0) status by microcontroller outputs,
as shown in Table I. The g-select
pins can be left unconnected for applications only requiring 1.5g selectivity.
The Sleep Mode pin can be connected to a logic inputs for mode switch. Set this pin low to enable
MMA7260QT in Sleep Mode that will only consumed trickle current. A high logic input at this
pin will switch the sensor to normal operation mode.

44
TILT SENSING
The MMA7260QT can respond to gravity or constant acceleration due to its capacitive detection
principle and mechanism. When gravity is perpendicular to an axis, its axis output is zero-
acceleration and therefore is half the VDD (i.e., 1.65V for typical 3.3V application). When gravity
is parallel to an axis and the gravity direction is toward the positive direction of that axis, its axis
output is half the VDD plus the selected sensitivity
The gravity response capability of the MMA7260 is useful for accurate tilt sensing with respect to
any orthogonal planes. Assume the φ, ρ and θ are the tilt angles of X-,Y- and Z-axis with respect
to horizon, respectively with known accelerations all the three tilt angles follow sinusoidal
relationship.
φ = arcsin( Accx)
ρ = arcsin( Accy)
θ =arcsin( Accz)
The resolution (acceleration changed per degree, i.e., the slope the sinusoidal curve) for any
axis also varies with tilt angles due to the sinusoidal relationship. Take the x-axis for
example, the maximal resolution can be obtained when its tilt φ increases from 0° or 180°,
and the minimal resolution occurs at φ approaches 90° or 270°. Therefore a modified tilt
calculation is suggested and is valid and applicable because it combines other axis outputs
and therefore a maximal resolution of tilt sensing can be retained across any rotation and
orientation with respect to any axis.

45
THEORY OF OPERATION
The ADXL335 is a complete 3-axis acceleration measurement system. The ADXL335 has a
measurement range of ±3 g mini-mum. It contains a polysilicon surface-micromachined sensor
and signal conditioning circuitry to implement an open-loop acceleration measurement
architecture. 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.
The sensor is a polysilicon surface-micromachined structure built on top of a silicon wafer.
Polysilicon springs suspend the structure over the surface of the wafer and provide a resistance
against acceleration forces. 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. Phase-sensitive demodulation techniques are then used to determine the magnitude
and direction of the acceleration.
The demodulator output is amplified and brought off-chip through a 32 kΩ resistor. The user then
sets the signal bandwidth of the device by adding a capacitor. This filtering improves
measurement resolution and helps prevent aliasing.
MECHANICAL SENSOR
The ADXL335 uses a single structure for sensing the X, Y, and Z axes. As a result, the three axes‟
sense directions are highly orthogonal and have little cross-axis sensitivity. Mechanical
misalignment of the sensor die to the package is the chief source of cross-axis sensitivity.
Mechanical misalignment can, of course, be calibrated out at the system level.

46
PERFORMANCE
Rather than using additional temperature compensation circuitry, innovative design techniques
ensure that high performance is built in to the ADXL335. As a result, there is no quantization
error or nonmonotonic behavior, and temperature hysteresis is very low (typically less than 3 mg
over the −25°C to +70°C temperature range.
X Axis zero biased temperature coefficient Vs=3v

47
Output(v)
APPLICATIONS INFORMATION
POWER SUPPLY DECOUPLING
For most applications, a single 0.1 μF capacitor, CDC, placed close to the ADXL335 supply pins
adequately decouples the accelerometer from noise on the power supply. However, in applications
where noise is present at the 50 kHz internal clock frequency (or any harmonic thereof), additional
care in power supply bypassing is required because this noise can cause errors in acceleration
measurement.
If additional decoupling is needed, a 100 Ω (or smaller) resistor or ferrite bead can be inserted in
the supply line. Additionally, a larger bulk bypass capacitor (1 μF or greater) can be added in
parallel to CDC. Ensure that the connection from the ADXL335 ground to the power supply
ground is low impedance because noise transmitted through ground has a similar effect to noise
transmitted through VS.
SETTING THE BANDWIDTH USING CX, CY, AND CZ
The ADXL335 has provisions for band limiting the XOUT, YOUT, and ZOUT pins. Capacitors
must be added at these pins to imple-ment low-pass filtering for antialiasing and noise reduction.
The equation for the 3 dB bandwidth is

48
F−3 dB = 1/(2π(32 kΩ) × C(X, Y, Z))
or more simply
F–3 dB = 5 μF/C(X, Y, Z)
The tolerance of the internal resistor (RFILT) typically varies as much as ±15% of its nominal
value (32 kΩ), and the bandwidth varies accordingly. A minimum capacitance of 0.0047 μF for
CX, CY, and CZ is recommended in all cases.
SELF-TEST
The ST pin controls the self-test feature. When this pin is set to VS, an electrostatic force is
exerted on the accelerometer beam. The resulting movement of the beam allows the user to test if
the accelerometer is functional. The typical change in output is −1.08 g (corresponding to −325
mV) in the X-axis, +1.08 g (or +325 mV) on the Y-axis, and +1.83 g (or +550 mV) on the Z-axis.
This ST pin can be left open-circuit or connected to common (COM) in normal use.Never expose
the ST pin to voltages greater than VS + 0.3 V. If this cannot be guaranteed due to the system
design (for instance, if there are multiple supply voltages), then a low VF clamping diode between
ST and VS is recommended.
DESIGN TRADE-OFFS FOR SELECTING FILTER CHARACTERISTICS:
THE NOISE/BW TRADE-OFF
The selected accelerometer bandwidth ultimately determines the measurement resolution (smallest
detectable acceleration). Filtering can be used to lower the noise floor to improve the resolution of
the accelerometer. Resolution is dependent on the analog filter bandwidth at XOUT, YOUT, and
ZOUT.
The output of the ADXL335 has a typical bandwidth of greater than 500 Hz. The user must filter
the signal at this point to limit aliasing errors. The analog bandwidth must be no more than half
the analog-to-digital sampling frequency to minimize aliasing. The analog bandwidth can be
further decreased to reduce noise and improve resolution.
The ADXL335 noise has the characteristics of white Gaussian noise, which contributes equally at
all frequencies and is described in terms of μg/√Hz (the noise is proportional to the square root of
the accelerometer bandwidth). The user should limit bandwidth to the lowest frequency needed by
the applica-tion to maximize the resolution and dynamic range of the accelerometer.

49
It is often useful to know the peak value of the noise. Peak-to-peak noise can only be estimated by
statistical methods. Table is useful for estimating the probabilities of exceeding various peak
values, given the rms value.
Output response VS orientation to Gravity
The ADXL335 output is ratiometric, therefore, the output sensitivity (or scale factor) varies
proportionally to the supply voltage. At VS = 3.6 V, the output sensitivity is typically 360 mV/g.
At VS = 2 V, the output sensitivity is typically 195 mV/g. The zero g bias output is also
ratiometric, thus the zero g output is nominally equal to VS/2 at all supply voltages.
The output noise is not ratiometric but is absolute in volts; therefore, the noise density decreases
as the supply voltage increases. This is because the scale factor (mV/g) increases while the noise
voltage remains constant. At VS = 3.6 V, the X-axis and Y-axis noise density is typically 120
μg/√Hz, whereas at VS = 2 V, the X-axis and Y-axis noise density is typically 270 μg/√Hz.

50
Self-test response in g is roughly proportional to the square of the supply voltage. However, when
ratiometricity of sensitivity is factored in with supply voltage, the self-test response in volts is
roughly proportional to the cube of the supply voltage. For example, at VS = 3.6 V, the self-test
response for the ADXL335 is approximately −560 mV for the X-axis, +560 mV for the Y-axis,
and +950 mV for the Z-axis.
At VS = 2 V, the self-test response is approximately −96 mV for the X-axis, +96 mV for the Y-
axis, and −163 mV for the Z-axis.
The supply current decreases as the supply voltage decreases. Typical current consumption at VS
= 3.6 V is 375 μA, and typi-cal current consumption at VS = 2 V is 200 μA.
Typical Current Consumption vs. Supply Voltage

51
OUR WORK AND RESULTS
This project can work on different modes :
Mode 1: In this mode the predefined gestures are used to control only direction of robot. Angular
differential drive is not obtained in this mode. The different gestures for controlling The Robot in
Mode1 is shown in figure.
Mode 2: This mode is for angular differential control of robot. The gestures recognized in this
mode are not only used for directions of robot, we can also control the speed of motors by which
we can obtain angular turns of robot. The data we obtained by accelerometer consists of X and Y
Co-ordinate values. First value indicates the X-Axis value and next value indicates the Y-Axis
Value. Based on these two X-Y –Axes values, we are going to control the direction and speed of
motor in a linear way. For differential speeds and differential motion of robot. For Differential
Controlling we are going with two other extra Parameters angular Velocity and Angular radius
which we get from converting cartesian form to polar form, The parameters are (R,Ø).Based on
these parameters the speed of different motor is controlled through Pulse Width Modulation when
the speed of these two motors are controlled we can get diffential motion of robot. maximum
speed of motor =150 R.P.M speed of motor is directly proportional to angle between X and Y-
Axis duty cycle of Motor is controlled by angle between X And Y Axis. Based on the relationship
between X andY coordinates values we decided the duty cycle.
X1=|86-X|
Y1=|86-Y|

52
Duty Cycle For Motor 1=(X1/4)*10
Duty Cycle For Motor 2=(Y1/4)*10
Mode 3: This mode is for camera movement control. The gestures recognized in this mode are
used to control Camera direction and movement. In this mode also we use pulse width to control
the speed of motor which is connected to camera, So that we can achieve angular motion for
camera position. The switching between modes is done by switches connected at transmitting end.
We use WinAvr compiler for coding.

Hand Gesture Recognition For Robot Control Page 53
COMPARISION WITH EXISTING SYSTEM
The major advantage of our system over other systems is that it provides real time palm gesture
recognition, leading to an effective and natural way for controlling robots.
Additional advantages are:
e than the existing systems. As it does not
involve any hardware requirement or configuration, there is little or no cost for the system's
implementation.
- a normal
accelerometer sensor is used for gesture recognition. This system can be installed on any of these
usable devices for gesture recognition. This provides flexibility to the user and the system is
portable.
-time gesture inputs from the user, processes these gesture
inputs to generate command signals. For both methods of gesture input, processing is done by a
method provided by the system, and it does not involve template matching to identify the finger
count or direction of palm.

APPLICATION AREAS OF HANDGESTURES SYSTEM
Hand gestures recognition system has been applied for different applications on different domains,
including; sign language translation, virtual environments, smart surveillance, robot control,
medical systems etc. overview of some hand gesture application areas are listed below.
Sign Language Recognition: Since the sign language is used for interpreting and explanations of
a certain subject during the conversation, it has received special attention. A lot of systems have
been proposed to recognize gestures using different types of sign languages .For example
recognized American Sign Language ASL using boundary histogram, MLP neural network and
dynamic programming matching recognized ,Japanese sign language JSL using Recurrent Neural
Network, 42 alphabet and 10 words recognized Arabic Sign language ArSL using two different
types of Neural Network, Partially and Fully Recurrent neural Network.
Robot Control: Controlling the robot using gestures considered as one of the interesting
applications in this field proposed a system that uses the numbering to count the five fingers for
controlling a robot using hand pose signs. The orders are given to the robot to perform a particular
task , where each sign has a specific meaning and represents different function for example, “one”
means “move forward”, “five” means “stop”, and so on.
Graphic Editor Control: Graphic editor control system requires the hand gesture to be tracked
and located as a preprocessing operation used 12 dynamic gestures for drawing and editing
graphic system. Shapes for drawing are; triangle, rectangular, circle, arc, horizontal and vertical
line for drawing, and commands for editing graphic system are; copy, delete, move, swap, undo,
and close .
Virtual Environments ( VEs): One of the popular applications in gesture recognition system is
virtual environments VEs, especially for communication media systems provided 3D pointing
gesture recognition for natural human computer Interaction HCI in a real-time from binocular
views. The proposed system is accurate and independent of user characteristics and environmental
changes .
Numbers Recognition: Another recent application of hand gesture is recognizing numbers.
Proposed an automatic system that could isolate and recognize a meaningful gesture from hand
motion of Arabic numbers from 0 to 9 in a real time system using HMM.

Television Control: Hand postures and gestures are used for controlling the Television device .
In [ a set of hand gesture are used to control the TV activities, such as turning the TV on and off,
increasing and decreasing the volume, muting the sound, and changing the channel using open and
close
EXPERIMENT AND DISCUSSIONS
Hardware part include the robotics part which include microcontroller, motor driver
L293D, and Accelerometer ADXL 335 sensor. For microcontroller we are using AVR 16.L293D
motor driver to drive the motor of the robot.Accelerometer ADXL 335sensor is used for the robot
control. Accelerometer can be used effectively translate finger and hand gesture into computer
interpreted signals. The sensitive direction of the accelerometer is in the plane of the hand.
Accelerometer ADXL 335 sensor are free scale enabling technology for acceleration . So in this
project, we propose a model of a robot based on “Human Machine Interfacing Device” utilizing
hand gestures to communicate with embedded systems for robot controlled. The 2-axis
accelerometer is selected to be the input device of this system, capturing the human hand
behaviors. When compared with other common input devices, this approach using, accelerometer
is more intuitive and easy to work, besides offering the possibility to control a robot by wireless
means In this project robot controlled is done by hand movement such as accelerometer sensor is
kept on the top of the hand . For particular direction of hand the robot move in different direction
such as forward, backward left and right direction. The accelerometer can measure the magnitude
and direction of gravity in addition to movement induced acceleration. In order to calibrate the
accelerometer we rotate the devices sensitive axis with respect to gravity and use the resultant
signal as an absolute measurement.
The robot does not require training because the robotic arm is fully controlled by the user. This
interfacing is done using wired communication but it can easily be switched to wireless with ease-
using
RF trans –receiver antenna or any other method. MEMS based sensors are crucial components in
automotive electronics, medical equipment, hand disk drives, computer peripheral wireless
devices and smart portable electronics such as cell phones and PDAS.

CONCLUSION
The main purpose of this project is to identify a particular human gesture and convey information
to the user pertaining to individual gesture. From the corpus of gestures, specific gesture of
interest can be identified, and on the basis of that, specific command for execution of action can be
given to robotic system. Overall aim is to make the computer understand human body language,
thereby bridging the gap between machine and human. Hand gesture recognition can be used to
enhance human–computer interaction without depending on traditional input devices such as
keyboard and mouse.
The objectives of this project has been achieved which was developing the hardware and software
for robot control using accelerometer. So in this project, we propose a model of a robot based on
“Human Machine Interfacing Device” utilizing hand gestures to communicate with embedded
systems for robot controlled. The 2-axis accelerometer is selected to be the input device of this
system, capturing the human hand behaviors. When compared with other common input devices,
this approach using accelerometer is more intuitive and easy to work, besides offering the
possibility to control a robot by wireless means. From observation that has been made, it clearly
shows that its movement is precise, accurate, and is easy to control and user friendly to use. The
robot control using accelerometer has been developed successfully as the movement of the robot
can be controlled precisely. In this project robot controlled is done by hand movement such as
accelerometer sensor is kept on the top of the hand . For particular direction of hand the robot
move in different direction such as forward, backward left and right direction. The accelerometer
ADXL 335 sensor can measure the magnitude and direction of gravity in addition to movement
induced acceleration. In order to calibrate the accelerometer we rotate the devices sensitive axis
with respect to gravity and use the resultant signal as an absolute measurement. Using this system,
a non-expert robot programmer can also control a robot quickly and in a natural way. We tested
our project in different direction we got good results in each direction. The accuracy of gestures
recognition should be improved. This kind of projects are applicable in field of security systems,
boarder security ,surveillance systems where we can send robots to detect the presence of people,
objects present in the environment. . It has the following advantages such as cost efficiency, low
power, miniaturization, high performance and integration.

REFERENCES
 Chao Hy Xiang Wang, Mrinal K. Mandal, Max Meng, and Donglin Li, “Efficient Face and
Gesture Recognition Techniques for Robot Control”, CCECE, 1757-1762, 2003.
 Asanterabi Malima, Erol Ozgur, and Mujdat Cetin, “A Fast Algorithm for Vision-Based
Hand Gesture
 Thomas G. Zimmerman, Jaron Lanier, Chuck Blanchard, Steve Bryson and Young Harvill,
“A Hand Gesture Interface Device”, 189-192, 1987.
 Gesture Controlled Robot using Kinecthttp://www.e-yantra.org/home/projects-
wiki/item/180-gesture-controlled-robot-using-firebirdv-and-kinect
 Pavlovic, V., Sharma, R. & Huang.T.S.: Visual interpretation of hand gestures for human-
computer interaction: A review. IEEE Transaction on Pattern Analysis and Machine
Intelligence, 19(7), pp 677–695,1997.
 Wu, Y. & Huang, T.S.: Vision-based gesture recognition: A review. In Lecture Notes in
Computer Science, GestureWorkshop,1999.
 Konstantinos G. Derpanis. : A Review of Vision-Based Hand Gestures. Internal Report,
Department of Computer Science.York University,2004.
 Watson, Richard.: A Survey of Gesture Recognition Techniques.Technical Report TCD-
CS-93-11, Department of Computer Science, Trinity College Dublin,1993.
 Sushmita Mitra and Tinku Acharya: Gesture Recognition: ASurvey. IEEE Transactions on
Systems, Man and Cybernetics -Part C: Applications and Reviews, Vol. 37, No. 3,2007.
 T.S. Hunang and V.I. Pavloic: Hand Gesture Modeling,Analysis, and Synthesis. Proc. of
International Workshop on Automatic Face-and gesture recognition, Zurich, pp.73-79,
1995
 Md. Hasanuzzaman, V. Ampornaramveth, Tao Zhang, M.A. Bhuiyan ,Y. Shirai and H.
Ueno,: Real-time Vision-based Gesture Recognition for Human Robot Interaction. In the
Proceedings of the IEEE International Conference on Robotics and Biomimetics,
Shenyang China ,2004
 X. Yin and M. Xie,: Finger identification in hand gesture based human–robot interaction.
J. Robot. and Auton. Syst., vol. 34, no. 4, pp. 235– 250,2001 F. S. Chen, C.M. Fu and C.L.
Huang,: H

Aacellerometer

Recommended

Recommended

More Related Content

What's hot

What's hot (20)

Viewers also liked

Viewers also liked (20)

Similar to Aacellerometer

Similar to Aacellerometer (20)

Recently uploaded

Recently uploaded (20)

Aacellerometer