CHAPTER 1

EMBEDDED SYSTEMS1.1 INTRODUCTION

An embedded system is a special-purpose computer system designed to perform

one or a few dedicated functions, sometimes with real-time computing constraints. It is

usually embedded as part of a complete device including hardware and mechanical parts.

In contrast, a general-purpose computer, such as a personal computer, can do many dif-

ferent tasks depending on programming. Embedded systems have become very important

today as they control many of the common devices we use.

Since the embedded system is dedicated to specific tasks, design engineers can

optimize it, reducing the size and cost of the product, or increasing the reliability and per-

formance. 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 con-

trollers, or the systems controlling nuclear power plants. Complexity varies from low,

with a single microcontroller chip, to very high with multiple units, peripherals and net-

works mounted inside a large chassis or enclosure.

1.2 BASIC BLOCKS OF EMBEDDED SYSTEMNow, the details of the various building blocks of the hardware of an embedded

system as shown in Fig 1.1 are

Central Processing Unit (CPU)

Memory (Read-only Memory and Random Access Memory)

Input Devices

Output devices

Communication interfaces

Application-specific circuitry

1

1.2.1 CENTRAL PROCESSING UNIT (CPU)

The Central Processing Unit (processor, in short) can be any of the following: mi-

crocontroller, microprocessor or Digital Signal Processor (DSP). A micro-controller is a

low-cost processor. Its main attraction is that on the chip itself, there will be many other

components such as memory, serial communication interface, analog-to digital converter

etc. So, for small applications, a micro-controller is the best choice as the number of ex-

ternal components required will be very less. On the other hand, microprocessors are

more powerful, but you need to use many external components with them. DSP is used

mainly for applications in which signal processing is involved such as audio and video

processing.

Fig 1.1: Block Diagram of Embedded System

1.2.2 MEMORYThe memory is categorized as Random Access Memory (RAM) and Read Only

Memory (ROM). The contents of the RAM will be erased if power is switched off to the

chip, whereas ROM retains the contents even if the power is switched off. So, the

firmware is stored in the ROM. When power is switched on, the processor reads the

ROM; the program is executed.

2

1.2.3 INPUT DEVICES

Unlike the desktops, the input devices to an embedded system have very limited

capability. There will be no keyboard or a mouse, and hence interacting with the embed-

ded system is not an easy task. Many embedded systems will have a small keypad-you

press one key to give a specific command. A keypad may be used to input only the digits.

Many embedded systems used in process control do not have any input device for user

interaction; they take inputs from sensors or transducers and produce electrical signals

that are in turn fed to other systems.

1.2.4 OUTPUT DEVICES

The output devices of the embedded systems also have very limited capability.

Some embedded systems will have a few Light Emitting Diodes (LEDs) to indicate the

health status of the system modules, or for visual indication of alarms. A small Liquid

Crystal Display (LCD) may also be used to display some important parameters.

1.2.5 COMMUNICATION INTERFACES

The embedded systems may need to, interact with other embedded systems at

they may have to transmit data to a desktop. To facilitate this, the embedded systems are

provided with one or a few communication interfaces such as RS232, RS422, RS485,

Universal Serial Bus (USB), and IEEE 1394, Ethernet etc.

1.2.6 APPLICATION-SPECIFIC CIRCUITRY

Sensors, transducers, special processing and control circuitry may be required for

an embedded system, depending on its application. This circuitry interacts with the pro-

cessor to carry out the necessary work. The entire hardware has to be given power supply

either through the 230 volts main supply or through a battery. The hardware has to design

in such a way that the power consumption is minimized.

Security is the condition of being protected against danger or loss. In the general

sense, security is a concept similar to safety. The nuance between the two is an added em-

phasis on being protected from dangers that originate from outside. Individuals or actions

that encroach upon the condition of protection are responsible for the breach of security.

The word "security" in general usage is synonymous with "safety," but as a technical

3

term "security" means that something not only is secure but that it has been secured. One

of the best options for providing good security is by using a technology named EMBED-

DED SYSTEMS.

1.3 MICROCONTROLLERIn the Literature discussing microprocessors, we often see the term Embedded

System. Microprocessors and Microcontrollers are widely used in embedded system

products. An embedded system product uses a microprocessor (or Microcontroller) to do

one task only. A printer is an example of embedded system since the processor inside it

performs one task only, namely getting the data and printing it. Contrast this with a Pen-

tium based PC can be used for any number of applications such as word processor, print-

server, bank teller terminal, Video game, network server, or Internet terminal. Software

for a variety of applications can be loaded and run. Of course the reason a pc can perform

myriad tasks is that it has RAM memory and an operating system that loads the applica-

tion software into RAM memory and lets the CPU run it.

In an Embedded system, there is only one application software that is typically

burned into ROM. An x86 PC contains or is connected to various embedded products

such as keyboard, printer, modem, disk controller, sound card, CD-ROM drives, mouse,

and so on. Each one of these peripherals has a Microcontroller inside it that performs

only one task. For example, inside every mouse there is a Microcontroller to perform the

task of finding the mouse position and sending it to the PC.

1.4 APPLICATION AREASNearly 99 per cent of the processors manufactured end up in embedded systems.

The embedded system market is one of the highest growth areas as these systems are

used in very market segment- consumer electronics, office automation, industrial automa-

tion, biomedical engineering, wireless communication, data communication, telecommu-

nications, transportation, military and so on.

Consumer appliances: At home we use a number of embedded systems which include

digital camera, digital diary, DVD player, video recorders etc.

Office automation: The office automation products using embedded systems are copy-

ing machine, fax machine, key telephone, modem, printer, scanner etc

4

Industrial automation: Today a lot of industries use embedded systems for process con-

trol. In hazardous industrial environment, where human presence has to be avoided, ro-

bots are used, which are programmed to do specific jobs.

Medical electronics: Almost every medical equipment in the hospital is an embedded

system. These equipments include diagnostic aids such as ECG, EEG, blood pressure

measuring devices, radiation, colonoscopy, endoscopy etc.

Computer networking: Computer networking products such as bridges, routers, Inte-

grated Services Digital Networks (ISDN), Asynchronous Transfer Mode (ATM), X.25

and frame relay switches are embedded systems which implement the necessary data

communication protocols

Telecommunications: In the field of telecommunications, the embedded systems can be

categorized as subscriber terminals and network equipment. The subscriber terminals

such as key telephones, ISDN phones, terminal adapters, web cameras are embedded sys-

tems. The network equipment includes multiplexers, multiple access systems, Packet As-

semblers Dissemblers (PADs), sate11ite modems etc.

Security: Security of persons and information has always been a major issue. We need

to protect our homes and offices; and also the information we transmit and store. Devel-

oping embedded systems for devices at homes, offices, airports etc. for authentication

and verification are embedded systems security applications is one of the most lucrative

businesses nowadays.

5

CHAPTER 2

GESTURE CONTROL ROBOT USING ACCELEROMETER

2.1 BLOCK DIAGRAM

TRANSMITTER

It consists of three modules in transmission section. They are as follows:

ADC Converter(LM324)

Encoder(HT12E)

Accelerometer(ADXL335)

RF Transmitter

Fig 2.1: Block diagram of transmitter

2.1.1 POWER SUPPLY

The input to the circuit is applied from the regulated power supply. The a.c. input

i.e., 230V from the mains supply is step down by the transformer to 12V and is fed to a

rectifier. The output obtained from the rectifier is a pulsating d.c voltage. So in order to

get a pure d.c voltage, the output voltage from the rectifier is fed to a filter to remove any

6

a.c components present even after rectification. Now, this voltage is given to a voltage

regulator to obtain a pure constant dc voltage.

DC MOTORS

Digital systems and microcontroller pins lack sufficient current to drive the cir-

cuits like relays, buzzer circuits, motors etc. While these circuits require around 10milli

amps to be operated, the microcontroller’s pin can provide a maximum of 1-2milli amps

current. For this reason, a driver such as a power transistor is placed in between the mi-

crocontroller and the motor.

VOLTAGE REGULATOR

Voltage regulator ICs is available with fixed (typically 5, 12 and 15V) or variable

output voltages. The maximum current they can pass also rates them. Negative voltage

regulators are available, mainly for use in dual supplies. Most regulators include some

automatic protection from excessive current ('overload protection') and overheating ('ther-

mal protection'). Many of the fixed voltage regulator ICs has 3 leads and look like power

transistors, such as the 7805 +5V 1A regulator shown on the right. The LM7805 is simple

to use. You simply connect the positive lead of your unregulated DC power supply (any-

thing from 9VDC to 24VDC) to the Input pin, connect the negative lead to the Common

pin and then when you turn on the power, you get a 5 volt supply from the output pin.

Voltage regulator

2.1.2 ACCELEROMETER

7

An accelerometer is an instrument for measuring acceleration, detecting and mea-

suring vibrations, or for measuring acceleration due to gravity (inclination). Accelerome-

ters can be used to measure vibration on vehicles, machines, buildings, process control

systems and safety installations. They can also be used to measure seismic activity, incli-

nation, machine vibration, dynamic distance and speed with or without the influence of

gravity.

2.1.3 ANALOG TO DIGITAL CONVERTER USING LM234

LM324 is used for Analog to Digital Conversion. It has four embedded op amps,

which requires Vcc (5V) and ground only. Analog signal is fed to the parallel combina-

tions of comparators, which produces an encoded signal corresponding to input analog

signal. The encoded signal is then applied to Digital Code Converter (a combinational

circuit), that will produce binary output. If the analog input exceeds the reference voltage

to any comparator that comparator turns ON.

2.1.4 HT12E

Encoders are software programs that are used for compressing information. Often,

the function of an encoder will also allow for the conversion of data from one format to

another. The HT12E is a 4bit encoder which encodes the input data applied on it. It con-

verts the parallel inputs into serial output. It encodes the 12 bit parallel data into serial for

transmission through an RF transmitter. These 12 bits are divided into 8 address bits and

4 data bits.  HT12E has a transmission enable pin which is active low. When a trigger

signal is received on TE pin, the programmed addresses/data are transmitted together

with the header bits via an RF or an infrared transmission medium.

2.1.5 RF TRANSMITTER (TX)

8

Transmitter is an electronic device which converts measurements from a sensor into

a signal, and sends it, via wires or wireless, to be received by control device located a dis-

tance away .The transmitter (Tx) operates at a frequency of 434 MHz which receives se-

rial data and transmits it wirelessly through RF through its antenna. This transmission oc-

curs at the rate of 1Kbps - 10Kbps.

2.2 BLOCK DIAGRAM OF RECEIVER It consists of three modules in this section. They are as follows

Microcontroller(AT89S52)

Decoder(HT12D)

Actuator(L293D)

RF Receiver

Fig 2.3 Block Diagram of Receiver

2.2.1 RF RECEIVER

9

RF receivers are the easiest way possible to add wireless control. It receives the

data which is transferred by the gesture device whose working is similar to the transmitter

module. The data pin is connected to HT12D decoder.

2.2.2 HT12D

The HT12D converts the serial data into parallel data which is received by the RF

receiver module. The input data is decoded when no error or unmatched codes are found.

A valid transmission is indicated by a high signal at Voltage Terminal pin.

2.2.3 MICROCONTROLLER (AT89S52)

The AT89S8252 is a low power, high performance CMOS 8-bit microcon-

troller with 8K bytes of in system programmable Flash memory. It is associated of cir-

cuitry like Crystal with capacitors, Reset circuitry, Pull up resistors (if needed) and so on.

The Microcontroller forms the heart of the project because it controls the devices being

interfaced and communicates with the devices according to the program being written.

2.2.4 ACTUATORS (L293D)

The Actuators are those devices which gives the movement or to do a task like

motors. In the real world there are various types of motors available which works on dif-

ferent voltages so we need motor driver for running them through the controller. To get

interfaced between motor and microcontroller we use L293D motor driver.

2.3 DESCRIPTIONA Gesture Controlled robot is a kind of robot which can be controlled by your

hand gestures not by old buttons. You just need to wear a small transmitting device in

your hand which included an acceleration meter. This will transmit an appropriate com-

mand to the robot so that it can do whatever we want. The transmitting device included a 

ADC for analog to digital conversion and an encoder IC(HT12E) which is use to encode

the four bit data and then it will transmit by an RF Transmitter module.

At the receiving end an RF Receiver module receives the encoded data and

decodes it by and decoder IC (HT12D). This data is then processed by a microcontroller

and finally our motor driver to control the motors. As user makes movements of his hand

10

in front of it, it senses and according to that it sends the signal for decision. Output from

accelerometer is gathered for process by microcontroller.

As per sensor output, the controller is made to work according to the program

written inside it and it sends the respective signal to third part which is motors. This is the

last part which drives the wheel of our robot. It uses two dc motors to make movement.

To drive them one motor driver is IC used which provides sufficient current to motors.

All this material is mounted on metal chesi. As we move our hand to right robot will

move to right side. Similar to this it will copy all our movements.

2.4 WORKING PRINCIPLE

Our gesture controlled robot works on the principle of accelerometer which

records hand movements and send that data to the comparator which assigns proper volt-

age level to the recorded movements. That information is then transferred to an encoder

which makes it ready for RF transmission. On the receiving end, the information is re-

ceived wirelessly via RF Decoded information. These decisions are passed to the motor

driver that is which triggers the motors in different configurations to make the robot

move in specific direction.

CHAPTER 3

8051 MICROCONTROLLER

11

3.1 INTRODUCTION

Microprocessors and microcontrollers are widely used in embedded systems prod-

ucts. 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 applica-

tions in which cost and space are critical.

Fig: Microcontroller(AT89S52)

The Intel 8051 is Harvard architecture, single chip microcontroller (µC) which

was developed by Intel in 1980 for use in embedded systems

8051 is an 8-bit processor, meaning that the CPU can work on only 8 bits of data

at a time. Data larger than 8 bits has to be broken into 8-bit pieces to be processed by the

CPU. 8051 is available in different memory types such as UV-EPROM, Flash and NV-

RAM.

The microcontroller used in this project is AT89C51. Atmel Corporation intro-

duced this 89C51 microcontroller. This microcontroller belongs to 8051 family. This mi-

crocontroller had 128 bytes of RAM, 4K bytes of on-chip ROM, two timers, one serial

port and four ports (each 8-bits wide) all on a single chip. AT89C51 is Flash type 8051.

The present project is implemented on Keil Uvision. In order to program the de-

vice, Proload tool has been used to burn the program onto the microcontroller.

12

The features, pin description of the microcontroller and the software tools used

are discussed in the following sections.

3.2 FEATURES OF AT89C51

4K Bytes of Re-programmable Flash Memory.

RAM is 128 bytes.

2.7V to 6V Operating Range.

Fully Static Operation: 0 Hz to 24 MHz.

Two-level Program Memory Lock.

128 x 8-bit Internal RAM.

32 Programmable I/O Lines.

Two 16-bit Timer/Counters.

Six Interrupt Sources.

Programmable Serial UART Channel.

Low-power Idle and Power-down Modes.

3.3 DESCRIPTION

The AT89C51 is a low-voltage, high-performance CMOS 8-bit microcomputer with 4K

bytes of Flash programmable memory. The device is manufactured using Atmel’s high-

density nonvolatile memory technology and is compatible with the industry-standard

MCS-51 instruction set. By combining a versatile 8-bit CPU with Flash on a monolithic

chip, the Atmel AT89C51 is a powerful microcomputer, which provides a highly flexible

and cost-effective solution to many embedded control applications.

13

In addition, the AT89C51 is designed with static logic for operation down to zero fre-

quency and supports two software selectable power saving modes. The Idle Mode stops

the CPU while allowing the RAM, timer/counters, serial port and interrupt system to con-

tinue functioning. The power-down mode saves the RAM contents but freezes the oscilla-

tor disabling all other chip functions until the next hardware reset

3.3.2 BLOCK DIAGRAM

Fig 3.2: Block Diagram of Microcontroller

3.3.1 PIN DIAGRAM

14

Fig 3.1 Pin Diagram of Microcontroller

3.3.3 PIN DESCRIPTION

Vcc

Pin 40 provides supply voltage to the chip. The voltage source is +5V.

GND

Pin 20 is the ground.

XTAL1 and XTAL2

XTAL1 and XTAL2 are the input and output, respectively, of an inverting amplifier that

can be configured for use as an on-chip oscillator, as shown in Figure 11. Either a quartz

crystal or ceramic resonator may be used. To drive the device from an external clock

source, XTAL2 should be left unconnected while XTAL1 is driven, as shown in the be-

low figure. There are no requirements on the duty cycle of the external clock signal, since

15

the input to the internal clocking circuitry is through a divide-by-two flip-flop, but mini-

mum and maximum voltage high and low time specifications must be observed.

Fig 3.3: Oscillator Connections

C1, C2 = 30 pF ± 10 pF for Crystals = 40 pF ± 10 pF for Ceramic Resonators

Fig 3.4: External Clock Drive Configuration

16

RESET

Pin9 is the reset pin. It is an input and is active high. Upon applying a high pulse to this

pin, the microcontroller will reset and terminate all the activities. This is often referred to

as a power-on reset.

EA (External access)

Pin 31 is EA. It is an active low signal. It is an input pin and must be connected to either

Vcc or GND but it cannot be left unconnected.

The 8051 family members all come with on-chip ROM to store programs. In such cases,

the EA pin is connected to Vcc. If the code is stored on an external ROM, the EA pin

must be connected to GND to indicate that the code is stored externally.

PSEN (Program store enable)

This is an output pin.

ALE (Address latch enable)

This is an output pin and is active high.

Ports 0, 1, 2 and 3

The four ports P0, P1, P2 and P3 each use 8 pins, making them 8-bit ports. All the ports

upon RESET are configured as input, since P0-P3 have value FFH on them.

Port 0(P0)

Port 0 is also designated as AD0-AD7, allowing it to be used for both address and data.

ALE indicates if P0 has address or data. When ALE=0, it provides data D0-D7, but when

ALE=1, it has address A0-A7. Therefore, ALE is used for demultiplexing address and

data with the help of an internal latch.

17

When there is no external memory connection, the pins of P0 must be connected to a

10K-ohm pull-up resistor. This is due to the fact that P0 is an open drain. With external

pull-up resistors connected to P0, it can be used as a simple I/O, just like P1 and P2. But

the ports P1, P2 and P3 do not need any pull-up resistors since they already have pull-up

resistors internally. Upon reset, ports P1, P2 and P3 are configured as input ports.

Port 1 and Port 2

With no external memory connection, both P1 and P2 are used as simple I/O. With exter-

nal memory connections, port 2 must be used along with P0 to provide the 16-bit address

for the external memory. Port 2 is designated as A8-A15 indicating its dual function.

While P0 provides the lower 8 bits via A0-A7, it is the job of P2 to provide bits A8-A15

of the address.

Port 3

Port 3 occupies a total of 8 pins, pins 10 through 17. It can be used as input or output. P3

does not need any pull-up resistors, the same as port 1 and port 2. Port 3 has an additional

function of providing some extremely important signals such as interrupts.

Table 3.1: Port 3 Alternate Functions

3.4 PROGRAMMING THE FLASH

18

The AT89C51 is normally shipped with the on-chip Flash memory array in the erased

state (that is, contents = FFH) and ready to be programmed. The programming interface

accepts either a high-voltage (12-volt) or a low-voltage (VCC) program enable signal.

The low-voltage programming mode provides a convenient way to program the

AT89C51 inside the user’s system, while the high-voltage programming mode is compat-

ible with conventional third party Flash or EPROM programmers. The AT89C51 is

shipped with either the high-voltage or low-voltage programming mode enabled. The re-

spective top-side marking and device signature codes are listed in the following table.

Table 3.2: Programming Flash

The AT89C51 code memory array is programmed byte-byte in either programming

mode.

3.4.1 PROGRAMMING ALGORITHM

Before programming the AT89C51, the address, data and control signals should be set up

according to the Flash programming mode table. To program the AT89C51, the follow-

ing steps should be considered:

1. Input the desired memory location on the address lines.

2. Input the appropriate data byte on the data lines.

3. Activate the correct combination of control signals.

19

4. Raise EA/VPP to 12V for the high-voltage programming mode.

5. Pulse ALE/PROG once to program a byte in the Flash array or the lock bits. The byte-

write cycle is self-timed and typically takes no more than 1.5 ms.

Repeat steps 1 through 5, changing the address and data for the entire array or until the

end of the object file is reached.

3.4.2 DATA POLLING

The AT89C51 features Data Polling to indicate the end of a write cycle. During a write

cycle, an attempted read of the last byte written will result in the complement of the writ -

ten datum on PO.7. Once the write cycle has been completed, true data are valid on all

outputs, and the next cycle may begin. Data Polling may begin any time after a write cy-

cle has been initiated.

Ready/Busy

The progress of byte programming can also be monitored by the RDY/BSY output signal.

P3.4 is pulled low after ALE goes high during programming to indicate BUSY. P3.4 is

pulled high again when programming is done to indicate READY.

3.4.3 Chip erase

The entire Flash array is erased electrically by using the proper combination of control

signals and by holding ALE/PROG low for 10 ms. The code array is written with all

“1”s. The chip erase operation must be executed before the code memory can be re-pro-

grammed.

20

Reading the Signature Bytes:

The signature bytes are read by the same procedure as a normal verification of locations

030H, 031H, and 032H, except that P3.6 and P3.7 must be pulled to a logic low. The val-

ues returned are as follows.

(030H) = 1EH indicates manufactured by Atmel

(031H) = 51H indicates 89C51

(032H) = FFH indicates 12V programming

(032H) = 05H indicates 5V programming

3.4.4 PROGRAMMING INTERFACE

Every code byte in the Flash array can be written and the entire array can be erased by us-

ing the appropriate combination of control signals. The write operation cycle is self timed

and once initiated, will automatically time itself to completion. All major programming

vendors offer worldwide support for the Atmel microcontroller series.

Table 3.3: Flash programming mode

21

Fig 3.5: Programming the Flash

Fig: 3.6: Verifying the Flas

22

CHAPTER 4

RF WIRELESS COMMUNICATIONS

4.1 INTRODUCTION

Radio frequency (RF) is a frequency or rate of oscillation within the range of

about 3 Hz to 300 GHz. This range corresponds to frequency of alternating current elec-

trical signals used to produce and detect radio waves. Since most of this range is beyond

the vibration rate that most mechanical systems can respond to, RF usually refers to oscil-

lations in electrical circuits or electromagnetic radiation.

What is RF?

RF itself has become synonymous with wireless and high-frequency signals, describing

anything from AM radio between 535 kHz and 1605 kHz to computer local area net-

works (LANs) at 2.4 GHz. However, RF has traditionally defined frequencies from a few

kHz to roughly 1 GHz. If one considers microwave frequencies as RF, this range extends

to 300 GHz. The following two tables outline the various nomenclatures for the fre-

quency bands. The third table outlines some of the applications at each of the various fre-

quency bands.

 

4.2 PROPERTIES OF RF

Electrical currents that oscillate at RF have special properties not shared by direct current

signals. One such property is the ease with which it can ionize air to create a conductive

path through air. This property is exploited by 'high frequency' units used in electric arc

welding. Another special property is an electromagnetic force that drives the RF current

to the surface of conductors, known as the skin effect. Another property is the ability to

appear to flow through paths that contain insulating material, like the dielectric insulator

of a capacitor. The degree of effect of these properties depends on the frequency of the

signals.

23

4.3 BRIEF DESCRIPTION OF RF

Radio frequency (abbreviated RF) is a term that refers to alternating current (AC) having

characteristics such that, if the current is input to an antenna, an electromagnetic (EM)

field is generated suitable for wireless broadcasting and/or communications. These fre-

quencies cover a significant portion of the electromagnetic radiation spectrum, extending

from nine kilohertz (9 kHz),the lowest allocated wireless communications frequency (it's

within the range of human hearing), to thousands of gigahertz(GHz).

When an RF current is supplied to an antenna, it gives rise to an electromagnetic field

that propagates through space. This field is sometimes called an RF field; in less techni-

cal jargon it is a "radio wave." Any RF field has a wavelength that is inversely propor-

tional to the frequency

s = 300/f

The RF spectrum is divided into several ranges, or bands. With the exception of the low-

est-frequency segment, each band represents an increase of frequency corresponding to

an order of magnitude (power of 10). The table depicts the eight bands in the RF spec-

trum, showing frequency and bandwidth ranges. The SHF and EHF bands are often re-

ferred to as the microwave spectrum.

4.4 RF ADVANTAGES No line of sight is needed.

Not blocked by common materials: It can penetrate most solids and pass through

walls.

Longer range.

It is not sensitive to the light.

It is not much sensitive to the environmental changes and weather conditions.

24

4.5 WHAT ARE THE MAIN REQUIREMENTS FOR THE COMMU-

NICATION USING RF?

RF Transmitter

RF Receiver

Encoder and Decoder

4.6 RF TRANSMITTER STT-433MHz

Fig 4.1: RF Transmitter

4.6.1 FACTORS INFLUENCED TO CHOOSE STT-433MHz

ABOUT THE TRANSMITTER

The STT-433 is ideal for remote control applications where low cost and longer

range is required.

The transmitter operates from a1.5-12V supply, making it ideal for battery-pow-

ered applications.

The transmitter employs a SAW-stabilized oscillator, ensuring accurate frequency

control for best range performance.

The manufacturing-friendly SIP style package and low-cost make the STT-433

suitable for high volume applications.

25

4.6.2 FEATURES

433.92 MHz Frequency

Low Cost

1.5-12V operation

Small size

4.6.3 PIN DESCRIPTION

Fig4.2: Pin Diagram of RF Transmitter

GND: Transmitter ground. Connect to ground plane

DATA: Digital data input. This input is CMOS compatible and should be driven with

CMOS level inputs.

VCC: Operating voltage for the transmitter. VCC should be bypassed with a .01uF

ceramic capacitor and filtered with a 4.7uF tantalum capacitor. Noise on the power sup-

ply will degrade transmitter noise performance.

ANT: 50 ohm antenna output. The antenna port impedance affects output power and

harmonic emissions. Antenna can be single core wire of approximately 17cm length or

PCB trace antenna.

4.5.5 APPLICATION

The typical connection shown in the above figure cannot work exactly at all times be-

cause there will be no proper synchronization between the transmitter and the microcon-

26

troller unit. i.e., whatever the microcontroller sends the data to the transmitter, the trans-

mitter is not able to accept this data as this will be not in the radio frequency range.

Fig 4.3 Application Circuit

Thus, we need an intermediate device which can accept the input from the microcon-

troller, process it in the range of radio frequency range and : send it to the transmitter.

4.7 RF RECEIVER STR-433 MHz

The data is received by the RF receiver from the antenna pin and this data is available on

the data pins.

Fig 4.4: RF Receiver

The data is received by the RF receiver from the antenna pin and this data is available on

the data pins. Two Data pins are provided in the receiver module. Thus, this data can be

used for further applications.

27

4.7.1 PIN DIAGRAM

Fig 4.5: Pin Diagram of RF Receiver

4.7.2 PIN DESCRIPTION

ANT: Antenna input.

GND: Receiver Ground. Connect to ground plane.

VCC (5V): VCC pins are electrically connected and provide operating voltage for the re-

ceiver. VCC can be applied to either or both. VCC should be bypassed with a .1μF ce-

ramic capacitor. Noise on the power supply will degrade receiver sensitivity.

DATA: Digital data output. This output is capable of driving one TTL or CMOS load. It

is a CMOS compatible output.

APPLICATIONS:

Similarly, as the transmitter requires an encoder, the receiver module requires a decoder.

The decoder used is HT12D from HOLTEK SEMICONDUCTOR INC.

28

CHAPTER 5

HARDWARE DESCRIPTION

5.1 HT12E- 212 SERIES OF ENCODERS

Fig 5.1: Pin Diagram

5.1.1 FEATURES

Operating voltage

2.4V~5V for the HT12A

2.4V~12V for the HT12E

Low power and high noise immunity CMOS technology

Low standby current: 0.1_A (typ.) at VDD=5V

Minimum transmission word

Four words for the HT12E

Built-in oscillator needs only 5% resistor

Data code has positive polarity

Minimal external components

HT12E: 18-pin DIP/20-pin SOP pack

29

5.1.2 GENERAL DESCRIPTION

The 212 encoders are a series of CMOS LSIs for remote control system applica-

tions. They are capable of encoding information which consists of N address bits and

12_N data bits. Each address/data input can be set to one of the two logic states. The pro-

grammed addresses/data are transmitted together with the header bits via an RF or an in-

frared transmission medium upon receipt of a trigger signal. The capability to select a TE

trigger on the HT12E further enhances the application flexibility of the 212 series of en-

coders.

5.1.3 BLOCK DIAGRAM OF ENCODER

Fig 5.2: Block Diagram

Table 5.2: Pin description of HT12E

5.1.4 FUNCTIONAL DESCRIPTION

Operation

The 212 series of encoders begin a 4-word transmission cycle upon receipt of a

transmission enable (TE for the HT12E active low). This cycle will repeat itself as long

30

as the transmission enable (TE or D8~D11) is held low. Once the transmission enable re-

turns high, the encoder output completes its final cycle and then stops as shown below.

Address/data waveform

Each programmable address/data pin can be externally set to one of the following

two logic states as shown below.

Address/data programming (preset)

The status of each address/data pin can be individually pre-set to logic _high_ or

_low_. If a transmission- enable signal is applied, the encoder scans and transmits the sta-

tus of the 12 bits of address/data serially in the order A0 to AD11 for the HT12E encoder.

During information transmission these bits are transmitted with a preceding synchroniza-

tion bit. If the trigger signal is not applied, the chip enters the standby mode and con-

sumes a reduced current of less than 1_A for a supply voltage of 5V. Usual applications

31

preset the address pins with individual security codes using DIP switches or PCB wiring,

while the data is selected by push buttons or electronic switches.

5.1.5 FLOW CHART

Fig 5.3: Flow Chart of Encoder

32

5.1.6 APPLICATION CIRCUIT

Fig 5.4: Application of Transmitter

5.2 HT12D-212 SERIES OF DECODERS

5.2.1 PIN DIAGRAM

Fig 5.5: Pin Diagram

5.2.2 FEATURES

Operating voltage: 2.4V~12V

Low power and high noise immunity CMOS technology

33

Low standby current

Capable of decoding 12 bits of information

Binary address setting

Received codes are checked 3 times

Address/Data number combination

HT12D: 8 address bits and 4 data bits

Built-in oscillator needs only 5% resistor

Valid transmission indicator

Easy interface with an RF or an infrared transmission medium

Minimal external components

Pair with Holtek’s 212 series of encoders

18-pin DIP, 20-pin SOP package

5.2.3 GENERAL DESCRIPTION

The 212 decoders are a series of CMOS LSIs for remote control system applica-

tions. They are paired with Holtek’s 212 series of encoders. For proper operation, a pair of

encoder/decoder with the same number of addresses and data format should be chosen.

The decoders receive serial addresses and data from a programmed 212 series of encoders

that are transmitted by a carrier using an RF or an IR transmission medium. They com-

pare the serial input data three times continuously with their local addresses. If no error or

unmatched codes are found, the input data codes are decoded and then transferred to the

output pins. The VT pin also goes high to indicate a valid transmission.

The 212 series of decoders are capable of decoding information that consists of N bits of

address and 12_N bits of data. Of this series, the HT12D is arranged to provide 8 address

bits and 4 data bits, and HT12F is used to decode 12 bits of address information.

5.2.4 BLOCKDIAGRAM OF DECODER

34

Fig 5.6: Block Diagram

5.2.5 PIN DESCRIPTION

Table 5.3: Pin description of HT12D

5.2.6 FUNCTIONAL DESCRIPTION

35

Operation

The 212 series of decoders provides various combinations of addresses and data

pins in different packages so as to pair with the 212 series of encoders. The decoders re-

ceive data that are transmitted by an encoder and interpret the first N bits of code period

as addresses and the last 12_N bits as data, where N is the address code number. A signal

on the DIN pin activates the oscillator which in turn decodes the incoming address and

data. The decoders will then check the received address three times continuously. If the

received address codes all match the contents of the decoder’s local address, the 12_N

bits of data are decoded to activate the output pins and the VT pin is set high to indicate a

valid transmission. This will last unless the address code is incorrect or no signal is re-

ceived. The output of the VT pin is high only when the transmission is valid. Otherwise it

is always low.

5.2.7 FLOW CHART

Fig 5.7: Flow Chart of Decoder

5.3 ACTUATOR (L293D)

36

5.3.1 PIN DIAGRAM

Fig 5.9: Pin Diagram

5.3.2 FEATURES

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)

5.3.3 DESCRIPTION

The L293 and L293D are quadruple high-current half-H drivers. The L293 is de-

signed 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 volt-

ages from 4.5 V to 36 V. Both devices are designed to drive inductive loads such as re-

lays, solenoids, dc and bipolar stepping motors, as well as other high-current/high-voltage

loads in positive-supply applications.

37

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 applica-

tions. On the L293, external high-speed output clamp diodes should be used for inductive

transient suppression.

A VCC1 terminal, separate from VCC2, is provided for the logic inputs to minimize de-

vice power dissipation. The L293 and L293D are characterized for operation from 0 to 70

degree Celsius.

5.3.4 BLOCK DIAGRAM

Fig 5.10: Block Diagram

38

CHAPTER 6

ACCELEROMETER ADXL335

6.1 INTRODUCTION

An accelerometer is an electromechanical device that will measure acceleration

forces. These forces may be static, like the constant force of gravity pulling at your feet,

or they could be dynamic - caused by moving or vibrating the accelerometer.

6.1.1 USES OF ACCELEROMETER

By measuring the amount of static acceleration due to gravity, you can find out

the angle the device is tilted at with respect to the earth. By sensing the amount of dy-

namic acceleration, you can analyze the way the device is moving. At first, measuring tilt

and acceleration doesn't seem all that exciting. However, engineers have come up with

many ways to make really useful products with them.

An accelerometer can help your project understand its surroundings better. Is it

driving uphill? Is it going to fall over when it takes another step? Is it flying horizontally

or is it dive bombing your professor? A good programmer can write code to answer all of

these questions using the data provided by an accelerometer.

6.1.2 WORKING OF AN ACCELEROMETER

There are many different ways to make an accelerometer! Some accelerometers

use the piezoelectric effect - they contain microscopic crystal structures that get stressed

by accelerative forces, which cause a voltage to be generated. Another way to do it is by

sensing changes in capacitance. If you have two microstructures next to each other, they

have a certain capacitance between them. If an accelerative force moves one of the struc-

tures, then the capacitance will change. Add some circuitry to convert from capacitance

to voltage, and you will get an accelerometer. There are even more methods, including

use of the piezoresistive effect, hot air bubbles, and light

39

6.1.3 TYPES OF ACCELEROMETER

There are several different principles upon which an analog accelerometer can be

built. Two very common types utilize capacitive sensing and the piezoelectric effect to

sense the displacement of the proof mass proportional to the applied acceleration.

6.2 CAPACITIVE

Accelerometers that implement capacitive sensing output a voltage dependent on

the distance between two planar surfaces. One or both of these are charged with an elec-

trical current. Changing the gap between the plates changes the electrical capacity of the

system, which can be measured as a voltage output. This method of sensing is known for

its high accuracy and stability. Capacitive accelerometers are also less prone to noise and

variation with temperature, typically dissipates less power, and can have larger band-

widths due to internal feedback circuitry. (Elwenspoek 1993)

6.3 PIEZOELECTRIC

Piezoelectric sensing of acceleration is natural, as acceleration is directly propor-

tional to force. When certain types of crystal are compressed, charges of opposite polarity

accumulate on opposite sides of the crystal. This is known as the piezoelectric effect. In a

piezoelectric accelerometer, charge accumulates on the crystal and is translated and am-

plified into either an output current or voltage.

Piezoelectric accelerometers only respond to AC phenomenon such as vibration

or shock. They have a wide dynamic range, but can be expensive depending on their

quality (Doscher 2005)

Piezo-film based accelerometers are best used to measure AC phenomenon such

as vibration or shock, rather than DC phenomenon such as the acceleration of gravity.

40

They are inexpensive, and respond to other phenomenon such as temperature, sound, and

pressure (Doscher 2005)

6.4 OTHER

There are many other types of accelerometer that are less important to musical ap-

plications, including:

Piezoresistive

Thermal

Null-balance

Servo force balance

Strain gauge

Resonance

Magnetic induction

Optical

Surface acoustic wave (SAW)

6.5 SPECIFICATIONS

A typical accelerometer has the following basic specifications:

Analog/digital

Number of axes

Output range (maximum swing)

Sensitivity (voltage output per g)

Bandwidth

Amplitude stability

The user selects the bandwidth of the accelerometer using the C X, CY, and CZ ca-

pacitors at the XOUT, YOUT, and ZOUT pins. Bandwidths can be selected to suit the ap-

41

plication, with a range of 0.5 Hz to 1600 Hz for the X and Y axes, and a range of 0.5 Hz

to 54350 Hz for the Z axis.

6.6 GENERAL DESCRIPTION

The ADXL335 is a small, thin, low power, complete 3-axis accelerometer with sig-

nal 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 ap-

plications, as well as dynamic Acceleration resulting from motion, shock, or vibration.

One of the most common inertial sensors is the accelerometer, a dynamic sensor

capable of a vast range of sensing. Accelerometers are available that can measure acceler-

ation in one, two, or three orthogonal axes. They are typically used in one of three modes:

As an intertial measurement of velocity and position

As a sensor of inclination, tilt, or orientation in 2 or 3 dimensions, as referenced

from the acceleration of gravity (1 g = 9.8m/s2);

As a vibration or impact (shock) sensor.

There are considerable advantages to using an analog accelerometer as opposed to

an inclinometer such as a liquid tilt sensor – inclinometers tend to output binary infor-

mation (indicating a state of on or off), thus it is only possible to detect when the tilt has

exceeded some thresholding angle.

Most accelerometers are Micro-Electro-Mechanical Sensors (MEMS). The basic

principle of operation behind the MEMS accelerometer is the displacement of a small

proof mass etched into the silicon surface of the integrated circuit and suspended by small

beams. Consistent with Newton's second law of motion (F = ma), as an acceleration is

applied to the device, a force develops which displaces the mass. The support beams act

as a spring, and the fluid (usually air) trapped inside the IC acts as a damper, resulting in

a second order lumped physical system. This is the source of the limited operational

42

bandwidth and non-uniform frequency response of accelerometers. For more information,

see reference to Elwenspoek, 1993.19

Fig 6.0: Block Diagram of ADXL335

An Accelerometer is a kind of sensor which gives an analog data while moving in

X,Y,Z direction or may be X,Y direction only depends on the type of the sensor. Here is

a small image of an Accelerometer shown. We can see in the image that there is some ar-

row showing if we tilt these sensors in that direction then the data at that corresponding

pin will change in the analog form.

A Microelectromechanical system (MEMS) is the technology of very small me-

chanical devices driven by electricity; it merges at the nano-scale into nanoelectrome-

chanical systems (NEMS) and nanotechnology.

Recent advances in microelectronic mechanical systems (MEMS) have made

high-performance, high-accuracy, low-cost accelerometers available on a single mono-

43

lithic IC. Accelerometers are used for acceleration and tilt measurements, vibration con-

trol, and cutoff switches for specific vibration conditions.

Fig 6.1: Accelerometer

The accelerometer output is ac-coupled to the on-board amplifier so that slower

variations due to tilt or any other signal of constant magnitude are rejected. To obtain the

desired output, this on-board amplifier is used as a bandpass filter, as shown in the

schematic. Then the signal is rectified and fed to a comparator, IC2. The output from the

comparator generates a square pulse each time the magnitude of the jerk is more than a

preset value. The comparator's output is used to trigger a one-shot, implemented using a

555 timer. The timer output, in turn, drives the alarm circuitry.

Recent advances in microelectronic mechanical systems (MEMS) have made

high-performance, high-accuracy, low-cost accelerometers available on a single mono-

lithic IC. Accelerometers are used for acceleration and tilt measurements, vibration con-

trol, and cutoff switches for specific vibration conditions.

6.7 PIN FUNCTIONAL DESCRIPTIONS

44

Table 6.1: Pin Functional Description

6.8 FEATURES

3 axis sensing small, low profile package

4mm x 4mm x 1.45mm LFCSP low power:350uA(typical)

Single operation: 1.8v to 3.6v 10,000g shock survival

excellent temperature stability BW adjustment with a single capacitor per axis

RoHS/WEEE lead-free complement

CHAPTER 7

SOFTWARE DESCRIPTION

45

7.1 KEIL SOFTWAREIn this module we will be using an Integrated Development Environment from

Keil Electronic. This IDE is called u VISION (pronounced “Micro Vision”) and versions

already exist for other popular microcontrollers including the 8051 and the Infineon

C16X family. keil u vision successfully integrates project management, editor, compiler

and debugger in one seamless front-end. Although we are concentrating on the LPC2000

family in this book, the Keil ARM tools can be used for any other ARM7 based micro-

controller. Use of keil u vision to write a program for ARM processor.

Keil compiler is software used where the machine language code is written and

compiled. After compilation, the machine source code is converted into hex code which

is to be dumped into the microcontroller for further processing. Keil compiler also sup-

ports C language code.

STEPS TO WRITE AN ASSEMBLY LANGUAGE PROGRAM IN

KEIL AND HOW TO COMPILE IT

1. Install the Keil Software in the PC in any of the drives.

2. After installation, an icon will be created with the name “Keil uVision3”. Just

drag this icon onto the desktop so that it becomes easy whenever you try to write

programs in keil.

3. Double click on this icon to start the keil compiler.

4. A page opens with different options in it showing the project workspace at the

leftmost corner side, output window in the bottom and an ash coloured space for

the program to be written.

5. Now to start using the keil, click on the option “project”.

6. A small window opens showing the options like new project, import project, open

project etc. Click on “New project”.

7. A small window with the title bar “Create new project” opens. The window asks

the user to give the project name with which it should be created and the destina-

tion location. The project can be created in any of the drives available. You can

create a new folder and then a new file or can create directly a new file.

46

8. After the file is saved in the given destination location, a window opens where a

list of vendors will be displayed and you have to select the device for the target

you have created.

9. The most widely used vendor is Atmel. So click on Atmel and now the family of

microcontrollers manufactured by Atmel opens. You can select any one of the mi-

crocontrollers according to the requirement.

10. When you click on any one of the microcontrollers, the features of that particular

microcontroller will be displayed on the right side of the page. The most appropri-

ate microcontroller with which most of the projects can be implemented is the

AT89C51. Click on this microcontroller and have a look at its features. Now click

on “OK” to select this microcontroller.

11. A small window opens asking whether to copy the startup code into the file you

have created just now. Just click on “No” to proceed further.

12. Now you can see the TARGET and SOURCE GROUP created in the project

workspace.

13. Now click on “File” and in that “New”. A new page opens and you can start writ -

ing program in it.

14. After the program is completed, save it with any name but with the .asm exten-

sion. Save the program in the file you have created earlier.

15. You can notice that after you save the program, the predefined keywords will be

highlighted in bold letters.

16. Now add this file to the target by giving a right click on the source group. A list of

options open and in that select “Add files to the source group”. Check for this file

where you have saved and add it.

17. Right click on the target and select the first option “Options for target”. A window

opens with different options like device, target, output etc. First click on “target”.

18. Since the set frequency of the microcontroller is 11.0592 MHz to interface with

the PC, just enter this frequency value in the Xtal (MHz) text area and put a tick

on the Use on-chip ROM. This is because the program what we write here in the

keil will later be dumped into the microcontroller and will be stored in the inbuilt

ROM in the microcontroller.

47

19. Now click the option “Output” and give any name to the hex file to be created in

the “Name of executable” text area and put a tick to the “Create HEX file” option

present in the same window. The hex file can be created in any of the drives. You

can change the folder by clicking on “Select folder for Objects”.

20. Now to check whether the program you have written is errorless or not, click on

the icon exactly below the “Open file” icon which is nothing but Build Target

icon. You can even use the shortcut key F7 to compile the program written.

21. To check for the output, there are several windows like serial window, memory

window, project window etc. Depending on the program you have written, select

the appropriate window to see the output by entering into debug mode.

22. The icon with the letter “d” indicates the debug mode.

23. Click on this icon and now click on the option “View” and select the appropriate

window to check for the output.

24. After this is done, click the icon “debug” again to come out of the debug mode.

25. The hex file created as shown earlier will be dumped into the microcontroller.

7.2 FLASH MAGIC:

NXP Semiconductors produce a range of Microcontrollers that feature both on-

chip Flash memory and the ability to be reprogrammed using In-System Programming

technology. Flash Magic is Windows software from the Embedded Systems Academy

that allows easy access to all the ISP features provided by the devices.

STEP 1 – CONNECTION SETTINGS: Before the device can be used the settings required to make a connection must be

specified. Select the desired COM port from the drop down list or type the desired COM

port directly into the box. If you enter the COM port yourself then you must enter it in

one of the following formats:

• COM n

Any other format will generate an error. So if you want to use COM 5 (which is

not present on the drop down list) you can directly type in either “COM 5” or “5”.

48

Select the baud rate to connect at. Try a low speed first. The maximum speed that

can be used depends on the crystal frequency on your hardware. You can try connecting

at higher and higher speeds until connections fail. Then you have found the highest baud

rate to connect at. Alternatively, some devices support high speed communications.

Please refer to the High Speed Communications section for information.

Select the device being used from the drop down list. Ensure you select the cor-

rect one as different devices have different feature sets and different methods of setting

up the serial communications.

Select the interface being used, if any. An interface is a device that connects be-

tween your PC and the target hardware. If you simply have a serial cable or USB to serial

cable connecting your COM port to the target hardware, then choose "None (ISP)".

Choosing the correct interface will automatically configure Flash Magic for that inter-

face, along with enabling and disabling the relevant features.

Enter the oscillator frequency used on the hardware. Do not round the frequency,

instead enter it as precisely as possible. Some devices do not require the oscillator fre-

quency to be entered, so this field will not be displayed.

Once the options are set ensure the device is running the on-chip Boot loader if

you are using a manual ISP entry method. Note that the connection settings affect all ISP

features provided by Flash Magic.

STEP 2 – ERASING: This step is optional, however if you attempt to program the device without first

erasing at least one Flash block, then Flash Magic will warn you and ask you if you are

sure you want to program the device.

Select each Flash block that you wish to erase by clicking on its name. If you

wish to erase all the Flash then check that option. If you check to erase a Flash block and

all the Flash then the Flash block will not be individually erased. If you wish to erase

only the Flash blocks used by the hex file you are going to select, then check that option.

For most devices erasing all the Flash also results in the Boot Vector and Status

Byte being set to default values, which ensure that the Boot loader will be executed on re-

set, regardless of the state of the PSEN pin or other hardware requirements. Only when

49

programming a Hex File has been completed will the Status Byte be set to 00H to allow

the code to execute. This is a safeguard against accidentally attempting to execute when

the Flash is erased. On some devices erasing all the Flash will also erase the security bits.

This will be indicated by the text next to the Erase all Flash option. On some devices

erasing all the Flash will also erase the speed setting of the device (the number of clocks

per cycle) setting it back to the default. This will be indicated by the text next to the Erase

all Flash option.

STEP 3 – SELECTING THE HEX FILE: This step is optional. If you do not wish to program a Hex File then do not select

one. You can either enter a path name in the text box or click on the Browse button to se-

lect a Hex File by browsing to it. Also you can choose Open… from the File menu.

Note that the Hex file is not loaded or cached in any way. This means that if the

Hex File is modified, you do not have to reselect it in Flash Magic. Every time the Hex

File is programmed it is first re-read from the location specified in the main window.

The date the Hex file was last modified is shown in this section. This information

is updated whenever the hex file is modified. The hex file does not need to be reselected.

Clicking on more info or choosing Information… from the File menu will display

additional information about the Hex file. The information includes the range of Flash

memory used by the Hex file, the number of bytes of Flash memory used and the percent-

age of the currently selected device that will be filled by programming the Hex file.

If the device supports programming and execution from RAM, for example the

ARM devices, then the hex file may contain records for the RAM. First the flash will be

programmed followed by the RAM. Programs loaded into RAM via a hex file may be ex-

ecuted using such features as the Go option.

STEP 4 – OPTIONS: Flash Magic provides various options that may be used after the Hex File has

been programmed. This section is optional, however Verify After Programming, Fill Un-

50

used Flash and Gen Block Checksums may only be used if a Hex File is selected (and

therefore being programmed), as they all need to know either the Hex File contents or

memory locations used by the Hex File.

Checking the Verify after Programming option will result in the data contained in

the Hex File being read back from Flash and compared with the Hex File after program-

ming. This helps to ensure that the Hex File was correctly programmed. If the device

does not support verifying then this item will be disabled.

Checking the Fill Unused Flash option will result in every memory location not

used by the Hex File being programmed with the value that sets all the bits to a pro-

grammed state. Once a location has been programmed with this feature it cannot be re-

programmed with any other value, preventing someone from programming the device

with a small program to read out the contents of Flash or altering the application’s opera-

tion.

Checking the Gen Block Checksums option will instruct Flash Magic to program

the highest location in every Flash block used by the Hex File with a special “checksum

adjuster value”. This value ensures that when a checksum is calculated for the whole

Flash Block it will equal 55H, providing the contents of the Flash block have not be al-

tered or corrupted.

STEP 5 – PERFORMING THE OPERATIONS: Step 5 contains a Start button. Clicking the Start button will result in all the se-

lected operations in the main window taking place. They will be in order:

Erasing Flash

Programming the Hex File

Verifying the Hex File

Filling Unused Flash

Generating Checksums

Programming the clocks bit

Programming the Security Bits

Executing the firmware

51

Once started progress information and a progress bar will be displayed at the bot-

tom of the main window. In addition the Start button will change to a cancel button. Click

on the cancel button to cancel the operation.

Note that if you cancel during erasing all the Flash, it may take a few seconds be-

fore the operation is cancelled.

Once the operations have finished the progress information will briefly show the

message “Finished…”. The Programmed Count shown next to the progress bar will in-

crement. This shows the total number of times the hex file has been programmed. Modi-

fying the hex file or selecting another hex file will reset the count. Alternatively, right-

clicking over the count provides a menu with the option to immediately reset the count.

Fig:7.2 Select Atmel

CHAPTER 8

RESULT ANALYSIS

52

In future several wheelchairs (up to 128) can be operated using a single remote

with accelerometer and PIC as master and various wheelchairs developed using micro-

controllers as slave.

This system can be extended by including GSM which sends an SMS during

emergency by assigning particular gesture command. By including GPS, position of the

wheelchair can also be known. Wheel chair can be fitted with direct mind reader. For ex-

ample, if a person is parlyzand cannot move his body parts, in that case it can be used.

Fig. 8.1 Move Forward Fig. 8.2 Move Backward

Fig 8.3 Move Right Fig 8.4 Move Left

FLOW CHART

53

start

54

Transmit data through accel-

erometer

Receive data by WS-RX-02

receiver

If data is 0101

If data is0010

If data is 1000

If data is 1010

Move robot forward

Move robot backward

Move robot left

Move robot right

stop

FIG 8.6: Gesture control robot

55

CONCLUSION

The project “GESTURE CONTROL ROBOT USING ACCELEROMETER

BASED” has been successfully designed and tested.

Presence of every module has been reasoned out and placed carefully thus con-

tributing to the best working of the unit.

In our project we have added special features by which our robot can overcome

so many problems in industry. If it is further developed then it can be used for military

application

56

ADVANTAGES

ADVANTAGES

We generally find people working in chemical industries under different haz-

ardous condition. These people suffer with many dangerous diseases like skin

cancer, lungs problem and many more.

So we finally thought of designing a robot that can copy that instant action of hu-

man being under various conditions and situations. So in that place of industry it

can be used. \

Gestures can be used to control interactions for entertainment purposes such as

gaming to make the game player’s experience more interactive or immersive

It is also used in mines

FUTURE SCOPE

In future we can design a wireless robot which can sense hand gesture by

using wireless technologies.

It can be used in military applications as a robotic vehicle which can be

handled by a soldier to avoid casualties.

Our system has shown the possibility that interaction with machines through

gestures is a feasible task and the set of detected gestures could be enhanced

to more commands by implementing a more complex model of a advanced

vehicle for not only in limited space while also in broader area as in the roads

too.

In the future, service robot executing many different tasks from private

movement to a full- fledged advanced automotive that can make disabled to

able in all sense

57

BIBLIOGRAPHY

The 8051 Micro controller and Embedded Systems

Muhammad Ali Mazidi

Janice Gillispie Mazidi

The 8051 Micro controller Architecture, Programming & Applications

Kenneth J.Ayala

Fundamentals Of Micro processors and Micro computers

B.Ram

Micro processor Architecture, Programming & Applications

Ramesh S. Gaonkar

Electronic Components

D.V. Prasad

Wireless Communications

Theodore S. Rappaport

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REFERENCES

http:// www.atmel.com

http:// www.beyondlogic.org

http://www.wikipedia.org

http://www.howstuffworks.com

http://www.alldatasheets.com

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