A PROJECT REPORT
ON
Handicap Assistance Device for Appliance Control Using User
Defined Gestures
Submitted In Partial Fulfillment of the Requirement for the Award of the Degree Of
BACHELOR OF TECHNOLOGY
IN
ELECTRONICS AND COMMUNICATION ENGINEERING
Jawaharlal Nehru Technological University, Hyderabad
BY
Naresh Mailarapu (07J81A0425)
Narayana reddy k (07J81A0423
Under the Guidance of
Miss T K Padmalatha
Asst Prof
Department of Electronics & Communication Engineering
P.INDRA REDDY MEMORIAL ENGINEERING COLLEGE
(Affiliated to Jawaharlal Nehru Technology University, Hyderabad, A.P)
Chevella, Ranga Reddy Dist-501503.
1
CERTIFICATE
This is to certify that this project work entitled “Handicap Assistance Device
for Appliance Control Using User Defined Gestures” is being submitted by
Naresh Mailarapu (07J81A0425)
Narayana reddy k (07J81A0423)
To the Jawaharlal Nehru Technological University, Hyderabad for the award of the
degree of Bachelor of Technology in Electronics and Communication Engineering is a
record of bonafide work carried out by them under our supervision and guidance
The results embodied in this project have not been submitted to any other university
or institute for the award of any degree or diploma
INTERNAL GUIDE
PRINCIPAL
HEAD OF THE DEPARTMENT
EXTERNAL EXAMINER
2
ACKNOWLEDGEMENT
We would like to express a deep sense of gratitude and thanks profusely to our guide
without the wise counsel and able guidance, it would have been impossible to complete the
project in this manner.
We express our deep sense of gratitude to Head of the Department, for his technical
support and guidance. His critical evaluation of work and suggestions has been of great help
to us.
We also express our gratitude to Principal of our college, for his guidance and cooperation during our course of study.
We are highly thankful to Prayog Labs Pvt Ltd., Hyderabad where every facility
for the project was provided. Their round the clock service and R&D laboratory facilities
helped us to complete the project in time.
Great acknowledgement is expressed to Coordinator, teaching and Non-teaching
staff members whose guidance cannot be ignored in completing this project.
3
INDEX
CONTENTS
Page No.
CHAPTER 1
INTRODUCTION
CHAPTER 2
EMBEDDED SYSTEMS
2.1 History
2.2 Tools
2.3 Resources
2.4 Real Time Issues
2.5Need For Embedded Systems
CHAPTER 3
HARDWARE DESCRIPTION
3.1 Introduction
3.2 Block diagram
3.3Main blocks of project
CHAPTER 4
MICROCONTROLLER
4.1 Introduction to Microcontrollers
4.2 Features
4.3 Pin diagram:
4.4 Pin Descriptions
4
CHAPTER 5
HARD WARE COMPONENTS
5.1 REGULATED POWER SUPPLY
5.1.1Introduction:
5.1.2Block Diagram:
5.1.3
Rectifiers
5.1.4 Filters:
5.1.5 Voltage Regulator:
5.1.6LED
5.2 ACCELEROMETER MMA 1260D
5.2.1 Features
5.2.2 Principle of operation
5.2.3 Pin diagram
5.2.4 Pin Description
5.3 ACCELEROMETER MMA2260D
5.3.1 Features
5.3.2 Principle of operation
5.3.3 Pin diagram
5.3.4 Pin Description
5.4 BUZZERS
5
5.5 CONTACT BUTTONS
5.6 5 DOF SENSOR
5.6.1 3-Axis ±3g MEMS Accelerometer (ADXL330)
5.6.1.1 Features
5.6.1.2 Principle of operation
5.6.1.3 Pin diagram
5.6.1.4 Pin Description
5.6.2 Integrated Dual-Axis Gyro IDG-300
5.6.2.1 Features
5.6.2.2 Principle of operation
5.6.2.3Pin diagram
5.6.2.4Pin Description:
5.7 WI.232FHSS-250-R
5.7.1 Features
5.7.2 Principle of operation
5.7.3 Pin diagram
5.7.4 Pin Description
6
CHAPTER 6
SCHAMATIC
6.1 Left hand controller
6.2 Right hand controller
6.3 Receiver
CHAPTER 7
SOFTWARE IMPLEMENTATION
7.1 Software Tools
7.2 Screen Shots
7.3 coding
CHAPTER 8
APPLICATIONS
CHAPTER 9
RESULTS
CHAPTER 10
CONCLUSION
CHAPTER11
BIBLIOGRAPHY
7
List of figures
Figure name
Page no
Fig :1 A modern example of embedded system
12
Fig:2 block diagram
Fig:3 Micro controller
15
Fig;4 Pin diagram of AT 644 PA
18
Fig 5: Regulated Power Supply
20
Fig 6: Circuit diagram of Regulated Power Supply with Led
21
Fig 7: Step-Down Transformer
22
Fig 8: Hi-Watt 9V Battery
24
Fig 9: Pencil Battery of 1.5V
25
8
Fig 10: Bridge rectifier: a full-wave rectifier using 4 diodes
26
Fig 11: DB107
27
Fig 12: Voltage Regulator
28
Fig 13: Inside a LED
29
Fig 14: Parts of a LED
29
Fig 15: Electrical Symbol & Polarities of LED
30
Fig 16:Transducer physical model
33
Fig 17: Pin diagram of mma1260d
33
Fig 19:Pin diagram of MMA2260d
Figure 20: Buzzer
Fig 21:pin diagram of ADXL330
Fig 22: pin diagram of IDG 300
9
Fig 23 pin diagram of WI.232FHSS-250-R
Abstract
Prayog Gloves is a wireless USB gesture input system that enables a person to use a
computer by performing intuitive hand and finger motions in the air. While wearing a glove
controller on the right hand, the user can move the cursor by forming a pointing gesture and
click by curling the index finger or thumb. Other right hand gestures enable scrolling and
provide access to various keyboard shortcuts. Wearing a glove device on the left hand allows
the user to type different keys through a combination of tilting the hand and touching
different portions of the palm and fingers with the thumb. The left and right controllers are
attached to each other but communicate to the computer wirelessly through a base station.
Mister Gloves uses a low-speed USB 1.1 interface and does not require the installation of
additional drivers.
Our gesture input system can be conveniently used by anyone who wishes not to be
tied down to a desk when using a computer, making it perfect for giving presentations or web
surfing from the couch. The intuitive hand motion controls also allow it to serve as an
alternative video game controller. Additionally, since our input system does not exert pressure
on the median nerve at the wrist while in use, it may prevent the development of carpal tunnel
syndrome and other repetitive stress injuries.
The motivation for our project was to create an intuitive input system that would be
easy and fun to use for computer applications that are not particularly keystroke-intensive,
such as surfing the web and playing (certain) video games.
Glove and Peregrine are both glove controllers that rely on various finger, thumb, and
palm touch actions. We decided to improve upon this concept by incorporating
accelerometers to detect the tilt of the hand as well, thus permitting wrist movements to
control the keystroke input in combination with the touch actions. This also allows for a
comparable assortment of possible keystrokes with a reduced number of touch or contact
sensors, which in turn enables us to define larger contact zones to allow easier activation.
10
EMBEDDED SYSTEMS
Embedded Systems:
An embedded system is a computer system designed to perform one or a few
dedicated functions often with real-time computing constraints. It is embedded as part of a
complete device often including hardware and mechanical parts. By contrast, a generalpurpose computer, such as a personal computer (PC), is designed to be flexible and to meet a
wide range of end-user needs. Embedded systems control many devices in common use
today.
Embedded systems are controlled by one or more main processing cores that
are typically either microcontrollers or digital signal processors (DSP). The key
characteristic, however, is being dedicated to handle a particular task, which may require very
powerful processors. For example, air traffic control systems may usefully be viewed as
embedded, even though they involve mainframe computers and dedicated regional and
national networks between airports and radar sites. (Each radar probably includes one or
more embedded systems of its own.)
Since the embedded system is dedicated to specific tasks, design engineers can
optimize it to reduce the size and cost of the product and increase the reliability and
performance. Some embedded systems are mass-produced, benefiting from economies of
scale.
Physically embedded systems range from portable devices such as digital
watches and MP3 players, to large stationary installations like traffic lights, factory
controllers, or the systems controlling nuclear power plants. Complexity varies from low,
with a single microcontroller chip, to very high with multiple units, peripherals and networks
mounted inside a large chassis or enclosure.
11
In general, "embedded system" is not a strictly definable term, as most
systems have some element of extensibility or programmability. For example, handheld
computers share some elements with embedded systems such as the operating systems and
microprocessors which power them, but they allow different applications to be loaded and
peripherals to be connected. Moreover, even systems which don't expose programmability as
a primary feature generally need to support software updates. On a continuum from "general
purpose" to "embedded", large application systems will have subcomponents at most points
even if the system as a whole is "designed to perform one or a few dedicated functions", and
is thus appropriate to call "embedded". A modern example of embedded system is shown in
fig: 2.1.
Fig :1 A modern example of embedded system
Labeled parts include microprocessor (4), RAM (6), flash memory
(7).Embedded systems programming is not like normal PC programming. In many ways,
programming for an embedded system is like programming PC 15 years ago. The hardware
for the system is usually chosen to make the device as cheap as possible. Spending an extra
dollar a unit in order to make things easier to program can cost millions. Hiring a
programmer for an extra month is cheap in comparison. This means the programmer must
make do with slow processors and low memory, while at the same time battling a need for
12
efficiency not seen in most PC applications. Below is a list of issues specific to the embedded
field.
History:
In the earliest years of computers in the 1930–40s, computers were sometimes
dedicated to a single task, but were far too large and expensive for most kinds of tasks
performed by embedded computers of today. Over time however, the concept
of programmable controllers evolved from traditional electromechanical sequencers, via solid
state devices, to the use of computer technology.
One of the first recognizably modern embedded systems was the Apollo
Guidance Computer, developed by Charles Stark Draper at the MIT Instrumentation
Laboratory. At the project's inception, the Apollo guidance computer was considered the
riskiest item in the Apollo project as it employed the then newly developed monolithic
integrated circuits to reduce the size and weight. An early mass-produced embedded system
was the Autonetics D-17 guidance computer for the Minuteman missile, released in 1961. It
was built from transistor logic and had a hard disk for main memory. When the Minuteman II
went into production in 1966, the D-17 was replaced with a new computer that was the first
high-volume use of integrated circuits.
Tools:
Embedded development makes up a small fraction of total programming.
There's also a large number of embedded architectures, unlike the PC world where 1
instruction set rules, and the UNIX world where there's only 3 or 4 major ones. This means
that the tools are more expensive. It also means that they're lowering featured, and less
developed. On a major embedded project, at some point you will almost always find a
compiler bug of some sort.
13
Debugging tools are another issue. Since you can't always run general programs on
your embedded processor, you can't always run a debugger on it. This makes fixing your
program difficult. Special hardware such as JTAG ports can overcome this issue in part.
However, if you stop on a breakpoint when your system is controlling real world hardware
(such as a motor), permanent equipment damage can occur. As a result, people doing
embedded programming quickly become masters at using serial IO channels and error
message style debugging.
Resources:
To save costs, embedded systems frequently have the cheapest processors that
can do the job. This means your programs need to be written as efficiently as possible. When
dealing with large data sets, issues like memory cache misses that never matter in PC
programming can hurt you. Luckily, this won't happen too often- use reasonably efficient
algorithms to start, and optimize only when necessary. Of course, normal profilers won't
work well, due to the same reason debuggers don't work well.
Memory is also an issue. For the same cost savings reasons, embedded
systems usually have the least memory they can get away with. That means their algorithms
must be memory efficient (unlike in PC programs, you will frequently sacrifice processor
time for memory, rather than the reverse). It also means you can't afford to leak memory.
Embedded applications generally use deterministic memory techniques and avoid the default
"new" and "malloc" functions, so that leaks can be found and eliminated more easily. Other
resources programmers expect may not even exist. For example, most embedded processors
do not have hardware FPUs (Floating-Point Processing Unit). These resources either need to
be emulated in software, or avoided altogether.
Real Time Issues:
Embedded systems frequently control hardware, and must be able to respond to them
in real time. Failure to do so could cause inaccuracy in measurements, or even damage
hardware such as motors. This is made even more difficult by the lack of resources available.
Almost all embedded systems need to be able to prioritize some tasks over others, and to be
14
able to put off/skip low priority tasks such as UI in favor of high priority tasks like hardware
control.
Need For Embedded Systems:
The uses of embedded systems are virtually limitless, because every day new
products are introduced to the market that utilizes embedded computers in novel ways. In
recent years, hardware such as microprocessors, microcontrollers, and FPGA chips have
become much cheaper. So when implementing a new form of control, it's wiser to just buy
the generic chip and write your own custom software for it. Producing a custom-made chip to
handle a particular task or set of tasks costs far more time and money. Many embedded
computers even come with extensive libraries, so that "writing your own software" becomes a
very trivial task indeed. From an implementation viewpoint, there is a major difference
between a computer and an embedded system. Embedded systems are often required to
provide Real-Time response. The main elements that make embedded systems unique are its
reliability and ease in debugging.
Debugging:
Embedded debugging may be performed at different levels, depending on the
facilities available. From simplest to most sophisticate they can be roughly grouped into the
following areas:

Interactive resident debugging, using the simple shell provided by the embedded
operating system (e.g. Forth and Basic)

External debugging using logging or serial port output to trace operation using either
a monitor in flash or using a debug server like the Remedy Debugger which even
works for heterogeneous multi core systems.

An in-circuit debugger (ICD), a hardware device that connects to the microprocessor
via a JTAG or Nexus interface. This allows the operation of the microprocessor to be
controlled externally, but is typically restricted to specific debugging capabilities in
the processor.

An in-circuit emulator replaces the microprocessor with a simulated equivalent,
providing full control over all aspects of the microprocessor.
15

A complete emulator provides a simulation of all aspects of the hardware, allowing all
of it to be controlled and modified and allowing debugging on a normal PC.

Unless restricted to external debugging, the programmer can typically load and run
software through the tools, view the code running in the processor, and start or stop its
operation. The view of the code may be as assembly code or source-code.
Because an embedded system is often composed of a wide variety of elements,
the debugging strategy may vary. For instance, debugging a software (and microprocessor)
centric embedded system is different from debugging an embedded system where most of the
processing is performed by peripherals (DSP, FPGA, co-processor). An increasing number of
embedded systems today use more than one single processor core. A common problem with
multi-core development is the proper synchronization of software execution. In such a case,
the embedded system design may wish to check the data traffic on the busses between the
processor cores, which requires very low-level debugging, at signal/bus level, with a logic
analyzer, for instance.
Reliability:
Embedded systems often reside in machines that are expected to run
continuously for years without errors and in some cases recover by them if an error occurs.
Therefore the software is usually developed and tested more carefully than that for personal
computers, and unreliable mechanical moving parts such as disk drives, switches or buttons
are avoided.
Specific reliability issues may include:

The system cannot safely be shut down for repair, or it is too inaccessible to repair.
Examples include space systems, undersea cables, navigational beacons, bore-hole
systems, and automobiles.

The system must be kept running for safety reasons. "Limp modes" are less tolerable.
Often backup s is selected by an operator. Examples include aircraft navigation,
reactor control systems, safety-critical chemical factory controls, train signals, engines
on single-engine aircraft.
16

The system will lose large amounts of money when shut down: Telephone switches,
factory controls, bridge and elevator controls, funds transfer and market making,
automated sales and service.
A variety of techniques are used, sometimes in combination, to recover from
errors—both software bugs such as memory leaks, and also soft errors in the hardware:

Watchdog timer that resets the computer unless the software periodically notifies the
watchdog

Subsystems with redundant spares that can be switched over to

software "limp modes" that provide partial function

Designing with a Trusted Computing Base (TCB) architecture[6] ensures a highly
secure & reliable system environment

An Embedded Hypervisor is able to provide secure encapsulation for any subsystem
component, so that a compromised software component cannot interfere with other
subsystems, or privileged-level system software. This encapsulation keeps faults from
propagating from one subsystem to another, improving reliability. This may also
allow a subsystem to be automatically shut down and restarted on fault detection.

Immunity Aware Programming
17
HARDWARE DESCRIPTION
Introduction:
In this chapter the block diagram of the project and design aspect of
independent modules are considered. Block diagram is shown in
BLOCK DIAGRAM
LEFT HAND CONTROL
14
X&Y
CONTACT
POWER
ACCELAR
BUTTONS
SUPPLY
OMETERS
PIEZO
TILT
LEFT
BUTTONS
HAND
ELECTRIC
BUZZER
MCU
RIGHT HAND CONTROL
(SENSOR READINGS
FLEX
5 DOF
SENSOR
SENSOR
THROUGH WIRE)
RIGHT
HAND MCU
TILT
BUTTONS
18
SENSOR INPUT
READINGS (WIRELESS)
PACKET
RADIO
BASE STATION
PACKET
PACKET
RADIO
RADIO
MCU
MCU
BASED
RxrRxr
BASED
DEBOUNCED AND FORMATTES
INPUT REQUEST
MCU
BASE
MCU
BASE
USB
USB
19
The main blocks of this project are:
Microcontrollers
Accelerometers
Flex sensor
5DOF sensor
Tilt state buttons
Piezo electric buzzers
Programming/controlling packet radios
20
Micro controller
fig:3 Micro
controller
Introduction to Microcontrollers:
Circumstances that we find ourselves in today in the field of
microcontrollers had their beginnings in the development of technology of integrated circuits.
This development has made it possible to store hundreds of thousands of transistors into one
chip. That was a prerequisite for production of microprocessors, and the first computers were
made by adding external peripherals such as memory, input-output lines, timers and other.
Further increasing of the volume of the package resulted in creation of integrated circuits.
These integrated circuits contained both processor and peripherals. That is how the first chip
containing a microcomputer, or what would later be known as a microcontroller came about.
Microprocessors and microcontrollers are widely used in embedded systems
products. Microcontroller is a programmable device. A microcontroller has a CPU in addition
to a fixed amount of RAM, ROM, I/O ports and a timer embedded all on a single chip. The
fixed amount of on-chip ROM, RAM and number of I/O ports in microcontrollers makes
them ideal for many applications in which cost and space are critical.
21
The microcontroller used in this project is ATmega644PA. The ATmega
families of microcontrollers are developed by Atmel corporation. The ATmega16 is a lowpower CMOS 8-bit microcontroller based on the AVR enhanced RISC architecture. By
executing powerful instructions in a single clock cycle, the ATmega16 achieves throughputs
approaching 1 MIPS per MHz allowing the system
designer to optimize
power
consumptionversus processing speed.
Features

High-performance, Low-power Atmel® AVR® 8-bit Microcontroller

Advanced RISC Architecture

131 Powerful Instructions – Most Single-clock Cycle Execution

32 x 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
o 16 Kbytes of In-System Self-programmable Flash program memory
o 512 Bytes EEPROM
o 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

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
 Peripheral Features
22

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 4.5V - 5.5V for ATmega16
23
Pin diagram:
Fig;4 Pin diagram of AT 644 PA
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 pinscan
24
provide internal pull-up resistors (selected for each bit). The Port A output buffers have
symmetricaldrive characteristics with both high sink and source capability. When pins PA0 to
PA7are used as inputs and are externally pulled low, they will source current if the internal
pull-upresistors 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 with
both high sink and source 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). The Port D output buffers have symmetrical drive characteristics with
both high sink and source 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 runnning.
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.
25
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.
REGULATED POWER SUPPLY:
Introduction:
Power supply is a supply of electrical power. A device or system that
supplies electrical or other types of energy to an output load or group of loads is called a power
supply unit or PSU. The term is most commonly applied to electrical energy supplies, less
often to mechanical ones, and rarely to others.
A power supply may include a power distribution system as well as primary or
secondary sources of energy such as

Conversion of one form of electrical power to another desired form and voltage,
typically involving converting AC line voltage to a well-regulated lower-voltage DC for
electronic devices. Low voltage, low power DC power supply units are commonly
integrated with the devices they supply, such as computers and household electronics.

Batteries.

Chemical fuel cells and other forms of energy storage systems.

Solar power.

Generators or alternators.
Block Diagram:
26
Transformer
Rectifier
Filter
Regulator
Fig 5: Regulated Power Supply
The basic circuit diagram of a regulated power supply (DC O/P) with led
connected as load is shown in fig.
Fig 6: Circuit diagram of Regulated Power Supply with Led
The components mainly used in above figure are

230V AC MAINS

TRANSFORMER

BRIDGE RECTIFIER(DIODES)

CAPACITOR

VOLTAGE REGULATOR(IC 7805)

RESISTOR

LED(LIGHT EMITTING DIODE)
The detailed explanation of each and every component mentioned above is as follows:
27
Transformation: The process of transforming energy from one device to another is called
transformation. For transforming energy we use transformers.
Transformers:
A transformer is a device that transfers electrical energy from one circuit to another
through inductively coupled conductors without changing its frequency. A varying current in
the first or primary winding creates a varying magnetic flux in the transformer's core, and
thus a varying magnetic field through the secondary winding. This varying magnetic
field induces a varying electromotive force (EMF) or "voltage" in the secondary winding.
This effect is called mutual induction.
If a load is connected to the secondary, an electric current will flow in the secondary
winding and electrical energy will be transferred from the primary circuit through the
transformer to the load. This field is made up from lines of force and has the same shape as a
bar magnet.
If the current is increased, the lines of force move outwards from the coil. If the
current is reduced, the lines of force move inwards.
If another coil is placed adjacent to the first coil then, as the field moves out or in, the
moving lines of force will "cut" the turns of the second coil. As it does this, a voltage is
induced in the second coil. With the 50 Hz AC mains supply, this will happen 50 times a
second. This is called MUTUAL INDUCTION and forms the basis of the transformer.
The input coil is called the PRIMARY WINDING; the output coil is the
SECONDARY WINDING. Fig: 3.3.4 shows step-down transformer.
28
Fig 7: Step-Down Transformer
The voltage induced in the secondary is determined by the TURNS RATIO.
For example, if the secondary has half the primary turns; the secondary will have
half the primary voltage.
Another example is if the primary has 5000 turns and the secondary has 500 turns,
then the turn’s ratio is 10:1.
If the primary voltage is 240 volts then the secondary voltage will be x 10 smaller =
24 volts. Assuming a perfect transformer, the power provided by the primary must equal the
power taken by a load on the secondary. If a 24-watt lamp is connected across a 24 volt
secondary, then the primary must supply 24 watts.
To aid magnetic coupling between primary and secondary, the coils are wound on a
metal CORE. Since the primary would induce power, called EDDY CURRENTS, into this
core, the core is LAMINATED. This means that it is made up from metal sheets insulated
from each other. Transformers to work at higher frequencies have an iron dust core or no core
at all.
Note that the transformer only works on AC, which has a constantly changing current
and moving field. DC has a steady current and therefore a steady field and there would be no
induction.
Some transformers have an electrostatic screen between primary and secondary. This
is to prevent some types of interference being fed from the equipment down into the mains
supply, or in the other direction. Transformers are sometimes used for IMPEDANCE
MATCHING.
We can use the transformers as step up or step down.
Step Up transformer:
29
In case of step up transformer, primary windings are every less compared to
secondary winding.
Because of having more turns secondary winding accepts more energy, and it releases
more voltage at the output side.
Step down transformer:
Incase of step down transformer, Primary winding induces more flux than the
secondary winding, and secondary winding is having less number of turns because of that it
accepts less number of flux, and releases less amount of voltage.
Battery power supply:
A battery is a type of linear power supply that offers benefits that traditional
line-operated power supplies lack: mobility, portability and reliability. A battery consists of
multiple electrochemical cells connected to provide the voltage desired. Fig: 3.3.5 shows HiWatt 9V battery
Fig 8: Hi-Watt 9V Battery
The most commonly used dry-cell battery is the carbon-zinc dry cell
battery. Dry-cell batteries are made by stacking a carbon plate, a layer of electrolyte paste,
and a zinc plate alternately until the desired total voltage is achieved. The most common drycell batteries have one of the following voltages: 1.5, 3, 6, 9, 22.5, 45, and 90. During the
30
discharge of a carbon-zinc battery, the zinc metal is converted to a zinc salt in the electrolyte,
and magnesium dioxide is reduced at the carbon electrode. These actions establish a voltage
of approximately 1.5 V.
The lead-acid storage battery may be used. This battery is rechargeable; it
consists of lead and lead/dioxide electrodes which are immersed in sulfuric acid. When fully
charged, this type of battery has a 2.06-2.14 V potential (A 12 volt car battery uses 6 cells in
series). During discharge, the lead is converted to lead sulfate and the sulfuric acid is
converted to water. When the battery is charging, the lead sulfate is converted back to lead
and lead dioxide A nickel-cadmium battery has become more popular in recent years. This
battery cell is completely sealed and rechargeable. The electrolyte is not involved in the
electrode reaction, making the voltage constant over the span of the batteries long service life.
During the charging process, nickel oxide is oxidized to its higher oxidation state and
cadmium oxide is reduced. The nickel-cadmium batteries have many benefits. They can be
stored both charged and uncharged. They have a long service life, high current availabilities,
constant voltage, and the ability to be recharged. Fig: 3.3.6 shows pencil battery of 1.5V.
Fig 9: Pencil Battery of 1.5V
Rectification:
The process of converting an alternating current to a pulsating direct current is called
as rectification. For rectification purpose we use rectifiers.
Rectifiers:
A rectifier is an electrical device that converts alternating current (AC) to direct
current (DC), a process known as rectification. Rectifiers have many uses including as
31
components of power supplies and as detectors of radio signals. Rectifiers may be made of
solid-state diodes, vacuum tube diodes, mercury arc valves, and other components.
A device that it can perform the opposite function (converting DC to AC) is known as
an inverter.
When only one diode is used to rectify AC (by blocking the negative or positive
portion of the waveform), the difference between the term diode and the term rectifier is
merely one of usage, i.e., the term rectifier describes a diode that is being used to convert AC
to DC. Almost all rectifiers comprise a number of diodes in a specific arrangement for more
efficiently converting AC to DC than is possible with only one diode. Before the
development of silicon semiconductor rectifiers, vacuum tube diodes and copper (I) oxide or
selenium rectifier stacks were used.
Bridge full wave rectifier:
The Bridge rectifier circuit is shown in fig: 3.3.7, which converts an ac voltage to
dc voltage using both half cycles of the input ac voltage. The Bridge rectifier circuit is shown
in the figure. The circuit has four diodes connected to form a bridge. The ac input voltage is
applied to the diagonally opposite ends of the bridge. The load resistance is connected
between the other two ends of the bridge.
For the positive half cycle of the input ac voltage, diodes D1 and D3 conduct,
whereas diodes D2 and D4 remain in the OFF state. The conducting diodes will be in series
with the load resistance RL and hence the load current flows through RL.
For the negative half cycle of the input ac voltage, diodes D2 and D4 conduct
whereas, D1 and D3 remain OFF. The conducting diodes D2 and D4 will be in series with the
load resistance RL and hence the current flows through RL in the same direction as in the
previous half cycle. Thus a bi-directional wave is converted into a unidire
Input
output
32
Fig 10: Bridge rectifier: a full-wave rectifier using 4 diodes
DB107:
Now -a -days Bridge rectifier is available in IC with a number of DB107. In our
project we are using an IC in place of bridge rectifier. The picture of DB 107 is shown in fig:
3.3.8.
Features:

Good for automation insertion

Surge overload rating - 30 amperes peak

Ideal for printed circuit board

Reliable low cost construction utilizing molded

Glass passivated device

Polarity symbols molded on body

Mounting position: Any

Weight: 1.0 gram
Fig 11: DB107
33
Filtration:
The process of converting a pulsating direct current to a pure direct current using
filters is called as filtration.
Filters:
Electronic filters are electronic circuits, which perform signal-processing functions,
specifically to remove unwanted frequency components from the signal, to enhance wanted
ones.
Regulation:
The process of converting a varying voltage to a constant regulated voltage is called
as regulation. For the process of regulation we use voltage regulators.
Voltage Regulator:
A voltage regulator (also called a ‘regulator’) with only three terminals appears to be
a simple device, but it is in fact a very complex integrated circuit. It converts a varying input
voltage into a constant ‘regulated’ output voltage. Voltage Regulators are available in a
variety of outputs like 5V, 6V, 9V, 12V and 15V. The LM78XX series of voltage regulators
are designed for positive input. For applications requiring negative input, the LM79XX series
is used. Using a pair of ‘voltage-divider’ resistors can increase the output voltage of a
regulator circuit.
It is not possible to obtain a voltage lower than the stated rating. You cannot use a
12V regulator to make a 5V power supply. Voltage regulators are very robust. These can
withstand over-current draw due to short circuits and also over-heating. In both cases, the
regulator will cut off before any damage occurs. The only way to destroy a regulator is to
34
apply reverse voltage to its input. Reverse polarity destroys the regulator almost instantly.
Fig: 3.3.11 shows voltage regulator.
Fig 12: Voltage Regulator
3.4. LED:
A light-emitting diode (LED) is a semiconductor light source. LED’s are used
as indicator lamps in many devices, and are increasingly used for lighting. Introduced as a
practical electronic component in 1962, early LED’s emitted low-intensity red light, but
modern versions are available across the visible, ultraviolet and infrared wavelengths, with
very high brightness. The internal structure and parts of a led are shown in figures 3.4.1 and
3.4.2 respectively.
Fig 13: Inside a LED
Fig 14: Parts of a LED
Working:
35
The structure of the LED light is completely different than that of the light bulb.
Amazingly, the LED has a simple and strong structure. The light-emitting semiconductor
material is what determines the LED's color. The LED is based on the semiconductor diode.
When a diode is forward biased (switched on), electrons are able to recombine with
holes within the device, releasing energy in the form of photons. This effect is called
electroluminescence and the color of the light (corresponding to the energy of the photon) is
determined by the energy gap of the semiconductor. An LED is usually small in area (less
than 1 mm2), and integrated optical components are used to shape its radiation pattern and
assist in reflection. LED’s present many advantages over incandescent light sources including
lower energy consumption, longer lifetime, improved robustness, smaller size, faster
switching, and greater durability and reliability. However, they are relatively expensive and
require more precise current and heat management than traditional light sources. Current
LED products for general lighting are more expensive to buy than fluorescent lamp sources
of comparable output. They also enjoy use in applications as diverse as replacements for
traditional light sources in automotive lighting (particularly indicators) and in traffic signals.
The compact size of LED’s has allowed new text and video displays and sensors to be
developed, while their high switching rates are useful in advanced communications
technology. The electrical symbol and polarities of led are shown in fig: 3.4.3.
Fig 15: Electrical Symbol & Polarities of LED
LED lights have a variety of advantages over other light sources:

High-levels of brightness and intensity
36

High-efficiency

Low-voltage and current requirements

Low radiated heat

High reliability (resistant to shock and vibration)

No UV Rays

Long source life

Can be easily controlled and programmed
Applications of LED fall into three major categories:

Visual signal application where the light goes more or less directly from the LED to
the human eye, to convey a message or meaning.

Illumination where LED light is reflected from object to give visual response of these
objects.

Generate light for measuring and interacting with processes that do not involve the
human visual system.
37
Accelerometer MMA 1260D (+/- 1.5g Z-Axis Micromachined
Accelerometer)
The accelerometer which we used here is MMA1260D The MMA series of silicon
capacitive, micromachined accelerometers features signal conditioning, a 2-pole low pass
filter and temperature compensation. Zero-g offset full scale span and filter cut-off are factory
set and
require no external devices. A full system self-test capability verifies system functionality.

Features
•
Integral Signal Conditioning
•
Linear Output
•
2nd Order Bessel Filter
•
Calibrated Self-test
•
EPROM Parity Check Status
•
Transducer Hermetically Sealed at Wafer Level for Superior Reliability
•
Robust Design, High Shock Survivability
Principle of operation
The device consists of a surface micromachined capacitive sensing cell (g-cell) and a
CMOS signal conditioning ASIC contained in a single integrated circuit package. The
sensing element is sealed hermetically at the wafer level using a bulk micromachined .cap
38
wafer.The g-cell is a mechanical structure formed from semiconductor materials (polysilicon)
using semiconductor processes (masking and etching). It can be modeled as twostationary
plates with a moveable plate in-between. The center plate can be deflected from its rest
position by subjecting the system to an acceleration.
When the center plate deflects, the distance from it to onefixed plate will increase by
the same amount that the distance to the other plate decreases. The change in distance is a
measure of acceleration.The g-cell plates form two back-to-back capacitors.As the center
plate moves with acceleration, the distance between the plates changes and each capacitor .S
value will change, (C = Aε/D). Where A is the area of the plate, ε is the dielectric constant,
and D is the distance between the plates.
The CMOS ASIC uses switched capacitor techniques to measure the g-cell capacitors
and extract the accelerationdata from the difference between the two capacitors. The ASIC
also signal conditions and filters (switched capacitor) the signal, providing a high level output
voltage that is ratio metric and proportional to acceleration.
Fig 16:Transducer physical model
Pin diagram
39
Pin no
1 thru
Pim name
Vss
4
5
6
7
8
9 thru 13
14 thru 16
Vout
Status
Vdd
Vss
ST
Trim Pins
------------
Description
Redundant connections to the int ernal VSS
and may be left unconnected.
Output voltage of the accelerometer.
Logic output pin used to indicate fault.
The power supply input.
The power supply ground.
Logic input pin used to initiate self-test.
Used for factory trim.Leave unconnected.
No internal connection.Leave unconnected.
Fig 17:
Pin
diagram of mma1260d
Pin Description:
Accelerometer MMA2260D (+/- 1.5g X-Axis Micromachined
Accelerometer)
40
The MMA series of silicon capacitive, micromachined accelerometers feature signal
conditioning, a 2-pole low pass filter and temperature compensation. Zerog offset full scale
span and filter cut-off are factory set and require no external devices. A full system self-test
capability verifies system functionality.
Features
 Integral Signal Conditioning
 High Sensitivity
 Linear Output
 2nd Order Bessel Filter
 Calibrated Self-test
 EPROM Parity Check Status
 Transducer Hermetically Sealed at Wafer Level for Superior Reliability
 Robust Design, High Shock Survivability
Principle of operation
The
Freescale
accelerometer
is
a
surface-micromachined
integrated-circuit
accelerometer. The device consists of a surface micromachined capacitive sensing cell (gcell) and a CMOS signal conditioning ASIC contained in a single integrated circuit package.
The sensing element is sealed hermetically at the wafer level using a bulk micromachined
.cap’’ wafer. The g-cell is a mechanical structure formed from semiconductor materials
(polysilicon) using semiconductor processes (masking and etching).
It can be modeled as a set of beams attached to a movable central mass that moves
between fixed beams. The movable beams can be deflected from their rest position by
subjecting the system to an acceleration .As the beams attached to the central mass move, the
distance from them to the fixed beams on one side will increase by the same amount that the
41
distance to the fixed beams on the other side decreases. The change in distance is a measure
of acceleration.
The g-cell beams form two back-to-back capacitors . As the central mass moves with
acceleration, the distance between the beams change and each capacitor’s value will change,
(C = NAε/D). Where A is the area of the facing side of the beam, e is the dielectric constant,
D is the distance between the beams, and N is the number of beams. The CMOS ASIC uses
switched capacitor techniques to measure the g-cell capacitors and extract the acceleration
data from the difference between the two capacitors. The ASIC also signal conditions and
filters (switched capacitor) the signal, providing a high level output voltage that is ratiometric
and proportional to acceleration.
Acceleration
Pin no
Pim name
Description
Fig 18: Transducer physical model
Pin diagram of MMA2260d
Fig 19:Pin diagram of MMA2260d
Pin Description:
42
1 thru
Vss
4
5
6
7
8
9 thru 13
14 thru 16
Vout
Status
Vdd
Vss
ST
Trim Pins
------------
Redundant connections to the int ernal VSS
and may be left unconnected.
Output voltage of the accelerometer.
Logic output pin used to indicate fault.
The power supply input.
The power supply ground.
Logic input pin used to initiate self-test.
Used for factory trim.Leave unconnected.
No internal connection.Leave unconnected.
Buzzer
Basically, the sound source of a piezoelectric sound component is a piezoelectric
diaphragm. A piezoelectric diaphragm consists of a piezoelectric ceramic plate which has
electrodes on both sides and a metal plate (brass or stainless steel, etc.). A piezoelectric
ceramic plate is attached to a metal plate with adhesives. Applying D.C. voltage between
electrodes of a piezoelectric diaphragm causes mechanical distortion due to the piezoelectric
effect. For a misshaped piezoelectric element, the distortion of the piezoelectric element
expands in a radial direction. And the piezoelectric diaphragm bends toward the direction.
The metal plate bonded to the piezoelectric element does not expand. Conversely, when the
piezoelectric element shrinks, the piezoelectric diaphragm bends in the direction Thus, when
43
AC voltage is applied across electrodes, the bending is repeated, producing sound waves in
the air.
To interface a buzzer the standard transistor interfacing circuit is used. Note that if a
different power supply is used for the buzzer, the 0V rails of each power supply must be
connected to provide a common reference.
If a battery is used as the power supply, it is worth remembering that piezo sounders
draw much less current than buzzers. Buzzers also just have one ‘tone’, whereas a
piezo sounder is able to create sounds of many different tones.
To switch on buzzer -high 1
To switch off buzzer -low 1
Notice (Handling) In Using Self Drive Method:
1) When the piezoelectric buzzer is set to produce intermittent sounds, sound may be heard
continuously even when the self drive circuit is turned ON / OFF at the "X" point shown in
Fig. 9. This is because of the failure of turning off the feedback voltage.
2) Build a circuit of the piezoelectric sounder exactly as per the recommended circuit shown
in the catalog. Life of the transistor and circuit constants is designed to ensure stable
oscillation of the piezoelectric sounder.
3) Design switching which ensures direct power switching.
4) The self drive circuit is already contained in the piezoelectric buzzer. So there is no need to
prepare another circuit to drive the piezoelectric buzzer.
5) Rated voltage (3.0 to 20Vdc) must be maintained. Products which can operate with voltage
higher than 20Vdc are also available.
6) Do not place resistors in series with the power source, as this may cause abnormal
oscillation. If a resistor is essential to adjust sound pressure, place a capacitor (about 1μF) in
parallel with the piezo buzzer.
44
7) Do not close the sound emitting hole on the front side of casing.
8) Carefully install the piezo buzzer so that no obstacle is placed within 15mm from the
sound release hole on the front side of the casing.
Figure 20: Buzzer
Contact buttons
Contact buttons simply a collection of 3M Red Dot electrodes. The input pins have
the internal pull-up resistor activated.when a contact sensor is touched by the thumb, the pin
receives a logic low value. Otherwise, it is pulled up to logic high.If the thumb does not push
firmly on the contact sensors, there is a significant amount of bouncing between logic high
and low due to vibrations and uneven metal surfaces. Thus, this requires some software
debouncing.
5 DOF SENSOR
It is actually a breakout board that combines the Analog Devices ADXL330, which is
a 3-axis +/- 3g accelerometer, and a 2-axis 500 degree/sec gyro, the IDG300. Used to control
mouse cursor movement since they measure rotational acceleration about an axis. The
accelerometer is mounted such that the Z-axis runs transverse to the plane of the hand, and
45
rotating the wrist left or right will change its angle towards the direction of gravity. This axis,
then, can be used to control horizontal cursor movement. The X-axis lies in the plane of the
hand and runs in the direction of the fingers. It changes value when hand tilts up and down.
Thus, it is used to control vertical cursor movement.
3-Axis ±3g MEMS Accelerometer (ADXL330)
GENERAL DESCRIPTION
The ADXL330 is a small, thin, low power, complete three axis accelerometer with
signal conditioned voltage outputs, all on a single monolithic IC. 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 1,600 Hz for X and Y axes, and a range of 0.5 Hz to
550 Hz for the Z axis.
FEATURES

3-axis sensing

Small, low-profile package (4 mm × 4 mm × 1.45 mm LFCSP )

Low power (200 μA at VS = 2.0 V (typical))

Single-supply operation (2.0 V to 3.6 V)

10,000 g shock survival

Excellent temperature stability

BW adjustment with a single capacitor per axis
Pin diagram
46
Fig 21:pin diagram of ADXL330
Pin description:
Pin no
Mnemonic
Description
1
NC
No Connect
2
ST
Self-Test
3
COM
Common
4
NC
No Connect
5
COM
Common
6
COM
Common
7
COM
Common
47
8
Zout
Z Channel Output
9
NC
No Connect
10
Yout
Y Channel Output
11
NC
No Connect
12
Xout
X Channel Output
13
NC
No Connect
14
Vs
Supply Voltage (2.0 V to 3.6 V)
15
Vs
Supply Voltage (2.0 V to 3.6 V)
16
NC
No Connect
Princeple of operation
The ADXL330 is a complete 3-axis acceleration measurement system on a single
monolithic IC. The ADXL330 has a measure-ment range of ±3 g minimum. 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 accelera-tion 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 meas-ured 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
48
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 band-width of the device by adding a capacitor. This filtering
improves measurement resolution and helps prevent aliasing.
Integrated Dual-Axis Gyro IDG-300
GENERAL DESCRIPTION
The IDG-300 is an integrated dual-axis angular rate sensor (gyroscope). It uses
InvenSense’s proprietary and patented MEMS technology with vertically driven, vibrating
masses to make a functionally complete, lowcost,dual-axis angular rate sensor. All
requiredelectronics are integrated onto a single chip with the sensor.
The IDG-300 gyro uses two sensor elements with novelvibrating dual-mass bulk
silicon configurations that sense the rate of rotation about the X- and Y-axis (in-plane
49
sensing). This results in a unique, integrated dual-axis gyro with guaranteed-by-design
vibration rejection and high cross-axis isolation. It is specifically designed for demanding
consumer applications requiring low cost, small size and high performance.
The IDG-300 gyro includes integrated electronics necessary for application-ready
functionality. It incorporates X- and Y-axis low-pass filters and an EEPROM for on-chip
factory calibration of the sensor. Factory trimmed scale factors eliminate the need for external
active components and end-user calibration.This product is lead-free and Green Compliant.
FEATURES
• Integrated X- and Y-axis gyro on a single chip
• Factory trimmed full scale range of ±500°/sec
• Integrated low-pass filters
• Superior vibration rejection over a wide
frequency range
• High cross-axis isolation by design
• 3V single supply operation
• 5000 g shock tolerance
• RoHS compliant (completely lead free)
• 6 x 6 x 1.5mm QFN package.
Pin diagram
50
Fig 22: pin diagram of IDG 300
Pin description
Number
Pin
Description
2, 22, 25, 38, 39, 40
GND
Ground
14, 29, 34
VDD
Positive supply voltage:
+3.0V to +3.3V
51
3
X-Rate Out
X-Rate Out
8
XAGC
Amplitude control filter
17
CPOUT
Charge pump capacitor
23
YAGC
Amplitude control filter
28
Y-Rate Out
Y-Rate Out
32
VREF
1.23V precision reference
output
1, 9, 10,11, 12, 13,
15,16, 18, 19, 20,
21, 30, 31, 33,
35, 36, 37
RESV
4 ,5, 6, 7, 24, 26, 27
NC
Reserved. Do not connect.
Used for factory trimming
Not internally connected
1.Overview
The IDG-300 gyro is a dual-axis gyroscope consisting of two independent vibratory
MEMS gyroscopes. One detects rotation about the X-axis; the other detects rotation about the
Y-axis. Each structure is fabricated using InvenSense’s proprietary bulk silicon technology.
The structures are covered and hermetically sealed at the wafer-level. The cover shields the
gyro from EMI. The gyroscope’s proof-masses are electrostatically oscillated at resonance.
An internal automatic gain control circuit precisely sets the oscillation of the proof masses.
When the sensor is rotated about the X- or Y-axis, the Coriolis effect causes a vibration that
can be detected by a capacitive pickoff. The resulting signal is amplified, demodulated, and
filtered to produce an analog voltage that is proportional to the angular rate.
2. Amplitude Control
The scale factor of the gyroscope depends on the amplitude of the mechanical motion
and the trim setting of the internal programmable gain stages. The oscillation circuit precisely
controls the amplitude to maintain constant sensitivity over the temperature range. The
capacitors (0.22μF, ±10%) connected to Pin 8 (XAGC) and Pin 23 (YAGC) are
compensation capacitors for the amplitude control loops.
52
3. External Low-Pass Filter
An external low-pass filter is recommended to attenuate high-frequency noise. The
cutoff frequency should be less than 2 kHz to attenuate tones above 10 kHz generated by
the vibrating proof-masses. Recommended RC values for the 2 kHz filter are RLPX/RLPY
and CLPX/CLPY are 750Ω and 0.1μF respectively. The sensor bandwidth is limited to 140
Hz by the internal low-pass filter. Applications that require lower bandwidth should choose
an external filter with a cutoff frequency less than 140Hz.
4. Scale Factor
The IDG-300 Rate-Out is not ratiometric to the supply voltage. The scale factor is
calibrated at the factory and is nominally independent of supply voltage.
5. Power Supply Filtering
The IDG-300 gyro should be isolated from system power supply noise by a
combination of an RC filter that attenuates high frequency noise and a Low Drop Out power
supply regulator (LDO) that attenuates low frequency noise. Figure below shows a typical
configuration.
6. VREF
VREF is a temperature independent voltage reference that can be used as a reference
for an ADC. There is offset between the zero rate output and VREF
WI.232FHSS-250-R
General description:The Wi.232FHSS module is one of a family of WiSE™ (Wireless Serial Engine) modules. A
WiSE module combines a state-of-the-art FSK data transceiver and a high-performance
protocol controller to create a complete embedded wireless communications link in a small
53
IC-style package. The 250mW RF transceiver is built around the Analog Devices ADF7020
IC, whereas the 25mW version uses the Semtech XE1203F transceiver IC. Both transceivers
are designed with the components necessary to facilitate operation in the 902-928MHz US
ISM band.
Features
• True UART to Antenna Solution
• 16-bit CRC Error Checking
• 153.6 kbit/ sec Maximum RF Data Rate
• 6 Hop Sequences
• GUID/MAC Addressing Mode
• Flexible User Addressing Mode
• Link Layer Supports Assured Delivery
• Small Size (0.80” x 0.935” x 0.12”) for the WI.232FHSS-25-R
• Small Size (1.20” x 1.20” x 0.20”) for the WI.232FHSS-250-R
• Low Power Standby, Sleep, and Deep Sleep Modes
• PHY, MAC, and Link Layer Protocol Built-in
Pin Diagram
54
Fig 23 pin diagram of WI.232FHSS-250-R
Pin description
Pin NO
Description
1
Ground
2
Exception Output
3
Buffer Empty
4
Command input – active low
5
UART receive input
6
UART transmit output
7
UART clear to send output – active low
8
Command Response indication
9
Analog RSSI
10
Reserved – ISP pin
11
ISP pin/Wake from DEEP SLEEP/Module Reset
12
Ground
13
Antenna port – 50 ohm
55
14
Ground
15
Ground
16
Ground
17
Ground
18
Ground
19
VCC – 2.7 to 3.6 VDC
UART Interface
Pin
Direction
Description
CTS
OUT
CMD
IN
RxD
IN
TxD
OUT
RTS
IN
Clear to send – this pin indicates to the host micro when it is ok to
send data.When CTS is high, the host micro should stop sending
data to the module until CTS returns to the low state.
Command – the host micro will bring this pin low to put the
module in command mode. Command mode is used to set and
read the internal registers that control the operation of the
module. When CMD is high, the module will transparently
transfer data to and from other modules on the same channel.
Note: If this pin is low when the module comes out of reset, the
non-volatile registers will be reset to their factory programmed
defaults. It is important to ensure that CMD is held high or left
floating during power-up under normal conditions.
Receive data input. UART data should be sent to the module with
no parity, 1 start bit, 1 stop bit, 8 data bits, least-significant bit
first.
Transmit data output. UART data will be sent by the module with
no parity, 1 start bit, 1 stop bit, 8 data bits, least-significant bit
first.
Currently unimplemented, this pin is reserved for future
use/reassignment.
Additional Module Pins
Additional module pins indicate the operational status of different functional blocks,
or provide additional control. There is no requirement that these pins be connected for normal
operation , However they can provide additional insight into the module. They may prove
useful in the optimization of the end application.
56
Buffer Empty (BE)
The BE pin indicates the state of the incoming UART buffer. When the module
receives data in the RxD pin,and the CMD pin is high, the BE pin is lowered until all data in
this buffer has been processed by the RF engine. If acknowledgement is not enabled, the BE
pin will be raised as soon as the RF engine processes the outgoing packets. If
acknowledgement is enabled, the buffer will not be updated until either the data transmissions
are acknowledged by the remote end, or the maximum number of retries has been exceeded.
Exception (EX)
The EX pin indicates whether a module exception has occurred. The pin is normally
low. When an exception occurs that passes masking the EX pin is raised. When the
regEXCEPTION register is read, the exception is cleared and the EX pin will return low. If
more than one exception occurs before the regEXCEPTION register is read, the old exception
will be overwritten by the new one.
RF Processing Incoming Packet (PROC_PKT)
Available on 250-R modules with firmware release 1.1.0 or later, the PROC_PKT pin
indicates whether the RF engine has determined there to be either valid or potentially valid
data incoming. The line is normally low (not processing). When awake and not transmitting,
the RF engine is constantly searching for an incoming signal. When scoring indicates that a
potential packet is inbound, this line is raised until the scoring falls below a given threshold
or the complete packet is received. It is possible that the packet scoring will fall below the
PROC_PKT threshold during reception, causing the line to be lowered. Such an instance can
occur when the module hops to a channel late in the transmitter’s extended preamble. Since
there aren’t a large number of valid bits to score, the line may fall low during the packet start
sequence. Once this sequence arrives, the PROC_PKT signal will re-raise and latch for the
duration of the packet reception.
57
Command Response (CMD_RSP)
The CMD_RSP pin is normally high. When the module’s command processor
responds to a command, such as a register read, the CMD_RSP pin lowers as the characters
are transmitted out of the TxD pin.Some host processors cannot react quickly enough to this
signal, and may not able to separate thecommand responses from incoming data. In this case,
the regCMDHALT register may be of use. This register controls the behavior of the TxD line
when the CMD pin is low. If this register is set to 0x01 and the CMD pin is low, the module
stops the flow of incoming RF data to the TxD pin, internally buffering it. Oncethe CMD pin
is raised, the buffered incoming RF data resumes transport out the TxD pin.
Reset (C2CK/RST)
The C2CK/RST pin is normally high. It is an open-drain input/output pin with an
integrated weak pull-up.Because it periodically operates as an output, care must be taken
when interfacing to this pin. When operating as an input, it has different functions depending
on the state the module is in.
SOFT WARES USED
58
About software:
Software used are:
Ki cad for PCB layout designing
AVR simulator for coding
AVR simulator PROCEDURE
Installing and Running
First, download and install the software (as administrator) in the order listed in the
COMPONENTS section above onto your PC. Reboot the PC afterward if you're prompted to
do so for the installation to complete properly.Once you have the software loaded on your
machine, you should be able to go ahead and run AVRStudio. If it didn't create a desktop
icon when it was installed, you'll just have to rough it and find it in the Windows Start menu
Creating a Project
Once AVR Studio is running you should be prompted for a project to work with, either by
creating a new one, or by using an existing project. In this case, click New Project
59
Select Project type AVR GCC, enter Project name simcounter, select both Create initial file
and Create folder and select (and remember!) a directory in which to put the new simcounter
project directory, then click Next.
Select Debug Platform AVR Simulator, and Device ATmega16, then click Finish.
60
You should now see the default window layout in AVR Studio. Because you checked Create
initial file when creating the project, AVR Studio has created a blank simcounter.c file and
pre-opened this file for you. If you click on the expand-group icon (the Plus icon) in front of
Source Files in the lefthand window, you'll find that simcounter.c has been added to the
simcounter project. If you needed to include any additional files source files for your project,
you would right-click on Source Files and choose the appropriate method to do this. You
won't need to for this example, but you will for labs later in the semester.
At this point, cut-and-paste the contents of simcounter.c from the final section of this
document into the blank window created for your project's simcounter.c. While you're at it,
save the contents of this file by doing a File->Save (or typing CTRL-S, or pressing the
floppy disk icon). If you had a copy of simcounter.c already on your computer, you could
also have used Add Existing File and pointed it to the file's location to add it to the project's
source files.
61
Create a new file called simcounter-PORTA.sti by right-clicking on Other Files in the lefthand window and selecting Create New File. Cut-and-paste the contents of this file from the
simcounter-PORTA.sti section at the bottom of this document into the window that was
created for this file, and similarly save it to disk.
62
Configuring and Building Project
In Project->Configuration Options->General, set Frequency to 8000000 and Optimization to O0 (note that this is capital-oh zero). It should be noted that this optimization setting is
usually not the most popular for generating code to be downloaded to a real microcontroller,
but it seems to be a safe choice for code to be simulated. In the future, once you're ready to
start programming your microcontollers in the lab, you'll often be directed to change this
setting -O2 as you'll see in subsequent weeks. Should you need to revert to simulating code
again generating code for a real processor, don't forget to reset this option back to -O0. If you
ever start seeing strange behavior when stepping execution through simulated programs, it's
probable that you weren't using -O0 for the code to be simulated. What usually happens is
that while stepping through your program, the cursor doesn't accurately advance from line to
line correctly. After changing this optimization setting to -O0, do a Build->Rebuild All, and
you should be all set.Please note that doing a Rebuild All rather than just a Build is always a
good idea after you have changed any project configuration options that have to do with
compilation. In fact, it's always safe(st) to do a Rebuild All rather than just a Build – it's just
that it may take somewhat longer.
63
In Debug->Select device and debug platform, set Debug Platform to AVR Simulator and
Device to Atmega16, then click Finish.
Compile the simcounter project with Build->Build (or F7). When the build is complete,
confirm that the last line in the Build window at the bottom of the screen is Build succeeded
with 0Warnings... as shown above. If this isn't what you see, somehow you boffed your cutand-paste, so go back and try it again. For some reason, there are certain configuration
settings in AVR Studio that cannot be set unless you've already started simulating a program,
and the following is one of them. To do so, initiate the simulationwith Debug->Start
Debugging. Now in Debug->AVR Simulator Options you should set Frequency to
8.00MHz..
64
Starting and Stepping through Execution
If you hadn't just done so immediately above, normally you'd start simulating the execution
of theprogram with Debug->Start Debugging, or by pressing the green right-facing triangle in
the toolbar
The first thing that the simulator then does is to start-up and then stop before the very
first simulated instruction is executed. It stops here to give you the chance to do all the setup
you need before starting the run
The important thing to notice at this point is that there should be a little yellow right-facing
arrow pointing to the opening curly-brace of the function main(). This arrow indicates the
next statement to be executed
the At any point when you have control of the running program (that is, when it isn't freerunning at fullspeed uninterrupted), you can step through the program slowly, line-by-line, at
your own pace. There are three ways to step – step into, step over, and step out. Step into and
step over behave similarly except when a function call is next statement to be executed. Step
into steps into (imagine that!) the function and pauses execution at the beginning of the called
function. Step over executes the entire function as a single statement and advances to the next
statement after the function call. Step over is a huge time-saver once you know that you don't
care about stepping through that function line-by-line. However if you want/need to see
what's going on in the function, by all means step into it. Step out is what's used once you're
in a function and you no longer care about what's going on inside the rest of itand just want to
get back to the code that called the function. Step Over completes executing the function and
65
gets you back to where you were when you called it. Just to get the hang of single-stepping,
we're going to start with Step Into. You can do this (and most of the simulator functions) one
of three ways. In decreasing order of pain, they are: in the menu bar do Debug->Step Into, in
the toolbar click on the Step Into icon (the one immediately to the right of the yellow arrow in
the toolbar, or by pressing the F11 key. Learn to know and love the F11 (and F10, which is
coming-up later) key, as the function keys are by far the easiest ones to use 500 times in an
hour
Press the F11 key once. It should now point to the statement where buttonPresses is
intialiized. Note again that this is the next statement to be executed. Press the F11 key again
and you should see the arrow pointing to
uint8_t thisState, prevState=0x00, changed
At this point, wouldn't it be cool to know that the value of buttonPresses is actually zero?
Well, you can, and there are two ways to do this. The first way is to use your cursor to point
to the variable buttonPresses anywhere in the source window and it'll pop-up a floating
balloon that says that the current value is 0 (along with some other details about the variable).
The second way is the power-user way, and you're also going to learn that now. You can
maintain a window on the screen containing any variables that you want to watch along with
their current values. This window is called the Watch window, and you can open it by doing
a View- >Watch. Do this and right-click the first cell under the label Name and click Add
Item. If you enter buttonPresses, it will give you an entry showing the current name and
66
value for this variable. Not only that, this value will be updated as you execute the program
under your control (it isn't updated as the program free-runs though). An alternate way to add
a new variable to be watched is to doubleclick in an empty Name field cell and you can enter
a variable name that way. If that weren't enough, there's third way to add a variable to the
watch window – just right-click on the variable name anywhere the editing window and
select Add Watch.
While you are here, use any of these three methods to add watch entries for the variables
thisState, prevState and changed. You should notice at this point in program execution that
we have notyet initialized these three variables. If you look where the yellow arrow is
pointing, we're still before their initialization statements. They are currently what's known as
“initialized to garbage”. This is programmer-speak for a variable that has been declared but
not yet set (initialized) to a known value –it contains whatever garbage was there when that
particular memory location was last used. It is a very,very, very bad thing to ever use a value
that has not been initialized. Multibillion dollar satellites (andperhaps your job with it) can be
lost forever when this happens, so it's usually best to try to avoid it.
So, observe that these three variables currently contain some random, likely non-zero, value.
Then go ahead an press F11 again to execute their initialization statements. Zero now for all
of them, presto
67
Before you go any farther you're going to learn how to view the I/O registers for the
microcontroller. All PORTA-related registers can be viewed by expanding the PORTA
group (click the plus-sign) in the right-hand I/O View window, as well as for all of the other
functional groupings of I/O registers. Here you will find the current simulated values for
PORTA, DDRA and PINA both there as well as in their own more-detailed-view window
below. Go ahead and expand the PORTB set also. Now if you can't see the full contents of
each of these entries' columns, especially in the lower of the two windows, stretch your
windows out so that you can see everything. In particular, you want to be able to see all eight
squares in the Bits column for each of the three PORTA/PORTB-related registers. These
types of registers are very important as they are the chip's interface to the outside world.
At this point, program execution should be right before the function call to init(). Let's
demonstrate Step Into first. The first time that you hit F11 you'll find yourself entering init().
As you hit F11 to execute the following two lines one at a time,
DDRA = 0x00; // PORTA used entirely for input
DDRB = 0xff; // PORTB used entirely for output
68
You should notice that the values for DDRA and DDRB (also known as Port A/B Data
direction register) in the I/O View window are updated. Especially note that the hollow
squares in the lower window are blackened for bits that contain high (1) values. This
representation is very useful for quickly visualizing which bits are set within an 8-bit value.
In the case of DDRB, all bits are high/black – assuming that you have the PORTB group
selected in the upper window. You will often be using these windows frequently when
following your code's execution.
At this point you should be done executing the last statement in init() and ready to
return. Using F11 will return you to the next statement after the one that called this function.
Since we've missed our only opportunity to demonstrate the use of Step Out (because there's
only one function call in our demonstration program, and we're never calling it again), let's
re-run the program from the beginning. You'll do this often when you get to a point where
you've missed something that you mindlessly blew-over and need to start over again.
Unfortunately, few simulators are able to backup through a simulation, so you'll have to start
at the beginning again.
To halt execution and start over again, press the Stop icon in the menu bar, the blue square
(or Debug- >Stop Debugging). To restart, as before, press the green triangle (essentially,
start) to continue and halt at the first executable statement. Press F11 until you get just inside
init(). Rather than stepping through the rest of the function that you no longer care about, you
can use Step Out to leave this function. As usual, you can use the Step Out icon to do this,
Debug->Step Out, or the appropriate function key.
To demonstrate the final stepping control, do a Debug->Stop Debugging, then Debug>Start Debugging to start the program again, and F11 until you are just about to call init()
again. Now use Step Over to execute init() without bothering to step into it. You'll do this
often once you are comfortable with what a function does and no longer care about crawling
69
through it again. Stepping into functions that you don't care about is often a huge waste of
time. Even better, notice that F10 is the keyboard shortcut for Step Over.
F10 is even more useful than F11 in many circumstances. To be honest, I never know
remember which one is which. I'll either use the menu or the toolbar to pick which one that I
want the first time, look at the FunctionKey label that is displayed, then just use the
FunctionKey from that point on. Just trust me and use the keys – repetitive-stress injuries
aren't pretty and every mouse click adds up, trust me. By the way, one thing that's easy to do
is to keep on pressing F11 and then end up in a function you didn't intend to enter. In that
case, just do a Step Out and you're back to where you wanted to be. In summary, those are
the three flavors of single-stepping and how each of them are useful, or more efficient,
depending on how deliberate you need to be when stepping through code.
70