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Friday, 4 June 2010

Automatic car parking indicator using Microcontroller

Conventionally, car parking systems does not have any intelligent monitoring system. Parking lots are monitored by human beings. All vehicles enter into the parking and waste time for searching for parking slot. Sometimes it creates blockage. Condition become worse when there are multiple parking lanes and each lane have multiple parking slots.

Use of automated system for car parking monitoring will reduce the human efforts. Display unit is installed on entrance of parking lot which will show LEDs for all Parking slot and for all parking lanes. Empty slot will be indicated by glowing the respective LED.

Block Diagram:

We have used Infra Red transmitters and Receivers for each parking slot. The IR Receivers are connected to AVR microcontroller. IR rays are obstructed when a car is parked in any parking slot. Thus AVR will come to know that which slot is empty and which slot is full. We have chosen IR module instead of RF module because we want a receiver having line of sight communication with the transmitter. But RF does not require line of sight communication. And in case of LDR, there is scope for false triggering due to sunlight or headlight of car. So considering all these points we have finalized to use IR module. For transmitter section we are going to use IR LEDs driven by a 555 timer IC. Timer IC will generate a frequency of 38 KHz, which will be given to IR LED

Pick and Place robot

In this highly developing society; time and man power are critical constrains for completion of task in large scales. the automation is playing important role to save human efforts in most of the regular and frequently carried works e.g. most of the industrial jobs like welding, painting, assembly, container filling etc. one of the major and most commonly performed work is picking and placing of jobs from source to destination. For this purpose, ‘pick and place robot ‘maybe used.
The pick and place robot is a microcontroller based mechatronic system that detects the object, picks that object from source location and places at desired location. For detection of object, infrared sensors are used which detect presence of object as the transmitter to receiver path for infrared sensor is interrupted by placed object. As soon as robot senses presence of object, it moves towards object, picks it with end effectors, and moves along way gantry and finally place it on destination.
If another object causes interrupt, it again does the same job. Whole process is controlled by micro controller.

Block Diagram:

ADC Interface ---- 4 channel (expandable) to detect object position.
Supply Voltage ---- 230V (AC).
8 bit microcontroller – P89V51RD2.
Motor interface – 3 motors : 2 motors in parallel.

This pick and place robot has two main mechanical components:
A] Robotic arm and end-effectors.
B] Gantry for moving the arm.

1. Initially we will assume the rest position of entire system, i.e. state when no object is placed.
2. At this stage, photo detector is having its output high, since receiver of sensor can receive photons from transmitter as no object I in its path to interrupt.
3. As soon as object is placed at the picking platform, the sensor gets interrupted and outputs low. This signal is sent to the microcontroller which is burnt with program which tells what operation is to be performed at this stage.
4. For understanding operation, let us rename the two motors used here. Let the name of gantry motor be M1 and that for end effecter motor is M2.
5. Now as microcontroller detects that object is placed, it moves motor M1 in say clockwise direction for a fixed time due to which whole arm moves towards picking platform.
6. As it reaches there, M1 stops and now motor M2 is started in say clockwise direction to hold the object by closing jaw. This motor also, is on for particular fixed time instant.
7. As M2 gets off, motor M1 is moved again in opposite (here anticlockwise) direction till the time it reaches the placing platform.
8. As it reaches placing platform, the motor M1 stops and M2 is switched ON in opposite (here anticlockwise) direction till it releases object properly on desired place.
9. If after this no object is detected, the robot is in rest position. Otherwise if another object is detected, steps from 3 are repeated till step 8.

1. We are using an 8 bit ADC PCF 8591, which uses an I2C bus protocol. It has 4 analog input channels AIN1, AIN2, AIN3 & 1 analog output channel AOUT. > Pin no. 1 i.e. channel 1 is connected IR sensor.
2. Except for the micro controller AT 89V51RD2, there is no other peripheral device connected to the ADC. Hence the hardware address lines (A0, Al & A2) are grounded.
3. Pin no. 9 and 10 are serial data line (SDA) and serial clock line (SCL) respectively. Both lines must be connected to a positive supply through a pull-up resistor. These pins are connected to the P1.6 & P1.7 of the micro controller.
4. Here we are not feeding the OSC (pin no. 11) with an external clock Signal, but using the ON chip oscillator. Hence the EXT pin (pin no.12) is directly grounded.
5. Vref (pin no. 14) is connected to the 5 V regulated supply.
II] Microcontroller: 1. PORT 0: (PIN NO. 39- PIN NO. 32): P0.0— P0.7 of the micro controller is connected to the motor driver circuit.
2. Pin no. 9 is RESET pin, which is connected to the reset circuit.
3. Pin no. 9 and 10 of ADC are serial data line (SDA) and serial clock line (SCL) respectively. Both are connected to a positive supply through a pull-up resistor. These pins are connected to the P1.6 & P1.7 of the micro controller.
1. The L293 and L293D are quadruple high-current drivers.TheL293is designed to provide bidirectional drive currents of up to 1 A at voltages from 4.5 V to 36 V. The L293D is designed to provide bidirectional drive currents of up to 600-mA at voltages from 4.5 V to 36 V. Both devices are designed to drive inductive loads such as relays, solenoids, dc and bipolar stepping motors, as well as other high-current/high-voltage loads in positive-supply applications.
2. 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.
3. When an enable input is high, the associated drivers are enabled and their outputs are active and in phase with their inputs. When the enable input is low, those drivers are disabled and their outputs are off and in the high-impedance state. With the proper data inputs, each pair of drivers forms a full-H (or bridge) reversible drive suitable for solenoid or motor applications.
4. A Vcc1 terminal, separate from Vcc2, is provided for the logic inputs to minimize device power dissipation.

1. It can be used in Production industry.
2. In mass production.
3. In Automobile Industry.
1. Bottle filling Plant.
2. Construction works.

1. Programming Microcontroller 8051 and customizing By Myke Predko
2. 8051 Microcontroller By Mazidi and Mazidi
3. 8051 Microcontroller By Kenneth Ayala

Component List
Sr no. Component Quantity Cost(Rs)
1 Transformer 12V, 1A 1 55
2 Diode 1N4007 4 5
3 Electrolytic capacitor 2200uf, 25V 1 3
4 Capacitor 100uf 2 5
5 IC 7805 1 8
6 IC 7812 1 8
7 Crystal 11.0592Mhz 1 20
8 IC L293d 1 95
9 P89V51RD2 1 125
10 PCF8591 1 125
11 IC Socket 40pin DIP 1 20
12 IC Socket 16pin DIP 2 10
13 2 pin connector 4 20
14 PCB 4*4 1 20
15 PCB 6*4 1 25
16 PCB 1 25
17 Resistors 5 3
18 Miscellaneous 10
19 Mechanical assembly 900

Landrover Robot Operated by Cellphone

In this project, the robot is controlled by a mobile phone that makes a call to the mobile phone attached to the robot.
In the course of a call, if any button is pressed, a tone corresponding to the button pressed is heard at the other end of the call.
This tone is called "Dual Tone Multiple-Frequency" (DTMF) tone. The robot perceives this DTMF tone with the help of the phone stacked on the robot.
The received tone is processed by the microcontroller with the help of DTMF decoder.
The microcontroller then transmits the signal to the motor driver ICs to operate the motors.
The metal detector circuit mounted on the robot detects any metal object around it.

Block Diagram:

Greenhouse Robot

Description in detail:
On the robot we have mounted a 12V battery as the power supply for the circuit and the motors.
When the user calls the mobile which is mounted on the robot the call is received by auto-answer mode.
As the call continues when the user presses a button on his handset the tone that is generated is decoded by the DTMF decoder and the command is passed to the microcontroller which is pre-programmed.
The Microcontroller then passes the command to the motor driver ICs for motion.
The metal detector when detects a metal and turns the buzzer on.

Applications: This robot can be used in the borders for disposing hidden land mines.
The robot can be used for reconnaissance or surveillance.
The robot can be used anywhere there is the service provider tower of the connection provided that is mounted on the robot.
The robot is small in size so can be used for spying.

Controller Area Network project

Description: Control Area Network controls the security of the Electronic equipments using the RS-485 protocol. We use CAN for Monitoring Sensors. Data can be stored in the System and the software is used for backup. We can get reports on hourly, weekly and monthly basis.
The Controller Area Network (CAN) bus is a multi-master message broadcast system that is suitable for systems where data contained in short messages are needed to be received at multiple locations simultaneously. Because messages are sent to all the nodes in a system, CAN is especially suited to systems where consistency in the received messages at all the receiving nodes is needed. In this case, all nodes are notified of the rejection, ensuring the data consistency across the network.
Messages are sent to all nodes, but their "message identifiers" indicate whether each node should act on the message. However, all nodes participate in indicating whether the message was sent correctly, increasing the reliability of the bus.
Designing and development process can be divided in to three Section.
1) Primarily Design
2) Embedded System
3) Monitoring Software

Block Diagram:

Controller Area Network

Description in detail: It mainly consist of following Modules
Module -1
This relates to Master circuits. (master Circuit)
Module -2
The module-2 is used to measure the RPM of the motor using the TACHOMETER which gives the voltages.
Module -3
The module-3 is used to measure of the Temperature of the motor using a TEMPERATURE SENSOR.
Module -4
The module-4 is used to rotate the angle of STEPPER MOTOR with the help of microcontroller programming

Remote Surveillance Vehicle using AVR ATmega16

In this project, the robot is controlled by a mobile phone that makes a call to the mobile phone attached to the robot.
In the course of a call, if any button is pressed, a tone corresponding to the button pressed is heard at the other end of the call.
This tone is called "dual tone multiple-frequency" (DTMF) tone. The robot perceives this DTMF tone with the help of the phone stacked on the robot.
The received tone is processed by the microcontroller with the help of DTMF decoder.
The microcontroller then transmits the signal to the motor driver IC"s to operate the motors.
The camera and micro-phone mounted on the robot will give the detailed information of where the robot is and who is around. The signal is then transmitted to the observer via audio/video transmitter-receiver.
The metal detector circuit mounted on the robot detects any metal object around it and transmits the signal wirelessly.

Block Diagram:

Water Spy - A Submarine Robot


Water spy is a specially designed Robot for under water operation. As its main aim is to work underwater so main objective should be that it should be capable of moving in any direction so we had provided it with such a driving power that it can move deep beneath water. To provide driving power six motors have been used. Also for surveillance robot that it should have capability of vision we are using a black and white CCD camera.
The robot is controlled by remote control. Wireless control of robot is achieved using DTMF code signals.
Microcontroller AT 89C51 has been used to control the direction of robot. H-bridge motor driver circuit has been used to provide reversible drive to the dc motors. Main body of Robot is made up of PVC pipes.


Project entitled “Water Spy- A Submarine Robot” is a robot which works under water.
Conventionally we see many robots which work on ground but we thought to accept challenge to make robot which could be operate beneath water.
Major challenge encountered to is to balance the body of robot under water. Firstly we had to select motors which could operate beneath water. So critical circuit should be isolated from water. Some of the function which we had successfully implemented on robot that it can travel up, down, forward, backward, left, right beneath water.
Two water tanks required to keep robot beneath water which force it to float and three air tanks are required to stabilize moment of robot under water. Robot is equipped with six DC motors which provide motion to robot in different directions. Also we can add CCD camera to see underneath water world.
Control of driving motor is done through H-bridge motor drives which can easily controls the motors for direction as well as start/stop function. Control signals provided to robot are through wireless remote implemented using FM with DTMF. In all seven function tags are provided on remote control which control total movement of robot.
Main problem encountered is to provide power to motor circuit. Batteries required are too heavy so power is supplied through cable. This problem could be further overcome by using light weight Ni-Cd batteries.


Water Spy Robot using Microcontroller



The code generator part employs a keyboard, IC UM 91215B and few other components. The IC UM 91215B is a ‘DUAL TONE MULTI FREQUENCY’ i.e. DTMF generator. Whenever a no. on the keyboard is pressed corresponding multiplexed frequency consisting of a lower band frequency and an upper band frequency is generated.

The DTMF code signals from UM 91215B is then frequency modulated and transmitted in air using FM transmitter. The carrier frequency is determined by coil L1 and trimmer capacitor C1 (they can be adjusted to change the frequency of the transmission). An antenna of 10 to 15cm length is used for satisfactory range. The antenna is necessary because the transmitter unit has to be housed in metallic cabinet to protect the frequency drift caused due to stray EM

The DTMF code signals from UM 91215B are frequency modulated and transmitted in air using FM transmitter. The antenna connected to FM receiver receives FM signals from remote control and demodulates them. Output of FM receiver is replica of the DTMF coded signal given to FM transmitter section. These DTMF coded signals are given to MT 8870 DTMF decoder. IC MT 8870 decodes the DTMF signals and gives 4 bit BCD output.

BCD output of DTMF receiver is then given to AT 89C51 Microcontroller. Depending on the BCD code at the output of receiver the software program inside the microcontroller controls the direction and selection of the motors on main body.

In the design of the motor driver circuit we had considered the following points:
• The required direction of rotation.
• The current and voltage requirement.
• The interfacing with the logic circuit.
• Quick Switching.
Considering all these requirements we choosed H-bridge motor driver for providing reversible drive to the motors. This circuit consumes very less power in stand still condition and provides the armature current of 3A (our requirement is 200mA).Here opposite pairs of transistors are triggered to generate the required polarity of voltage as per the required direction of motor.

Main body consists of water filled tank, air filled tank, stabilization tank & motor with fans attached to it. Air filled and water filled tanks are made up of PVC pipes. Stabilization tank is used for balancing of main body beneath water while the rotating fans provide motion to the body.

• 9v Ni-Cd battery: This battery is used as a supply for transmitter circuit.
• 5v supply: 5v supply is used to provide power to the control circuit.
• 12v supply: 12v supply is used to provide power to the motor driver circuit.


Parameter : Value
Power Supply

Transmission Unit

Encoding Unit

Decoding Unit

Operating Frequency Of Crystal

Transmission Frequency

Control Unit

Motor Driver













Input: 230v,50Hz +-10%
Output: +5v, +12v.

FM transmitter and receiver.

UM 91215B(Tone Dialing Mode)

MT 8870.



Microcontroller AT 89C51

NEC B882

Common cathode 7 segment

Black & White CCD camera

DC 12v


Water Spy Submarine Robot is specially designed for under water applications. Wireless control is provided to the robot using the concept of DTMF.IC 91215B is a DTMF generator, when a key on keypad is pressed it generates a particular DTMF code. These DTMF code single is then frequency modulated using FM transmitter. Antenna radiates this FM signal in to its surrounding.

At receiver section FM receiver is tuned to receive the transmitted signals. It then demodulates the received signal and its output is replica of transmitted DTMF code. This DTMF code signal is given as input to the IC 8870 DTMF decoder. It decodes the DTMF code signal and gives 4-bit BCD code at its output pins. Decoder generates a unique BCD code for each key pressed on the keypad. This BCD output is connected to the input port of AT89C51 microcontroller. Based on this BCD code microcontroller generates control signals using software program inside it, which controls selection and direction of the motors.

Output of microcontroller is given to the H-bridge motor driver circuit which provides reversible drive to the motors used. Thus implementing all, we could operate the robot successfully underwater.


1. Start.
2. Point DPTR to table 1 containing data equivalent to the output of decoder.
3. Read the data at port 1.
4. Compare port 1data with data pointed by DPTR.
5. If compared data is equal, point DPTR to table 2 & send corresponding data at port 2.
6. Send corresponding data at port 0 for display.
7. Jump to step 2.


1. All the tracks of PCB are checked.
2. We checked continuity of all tracks.
3. High voltage was applied between two independent tracks to check any hair size short or air gap.

1. Polarities of all the components like capacitors, connectors etc are checked.
2. It is seen that all the IC sockets are soldered properly.

1. All the IC sockets and power supply are soldered and continuity is checked
2. Also VCC and GND voltage are checked.
3. Voltages at all the pins of the microcontroller are checked with respect to ground.
4. Values of all possible components are checked on multimeter.

1. DTMF tones generated where tested using a speaker connected at its output.
2. We received DTMF signal on normal FM receiver while checking the FM transmitter.
3. We tested DTMF decoder using LED connected at the output lines.
4. Microcontroller’s working was ensured by debugging the program.


1. An ultrasonically controlled robot submarine for pipe inspection.
A model submarine with four legs and umbilical is described that is both radio and ultrasonically controlled to walk in pipe. The ultrasonic communication system is described together with the problem and solutions encountered and worked out. Finally, the leg kinematics, and their actuation system and control are discussed.

2. Autonomous Underwater Vehicles
Autonomous underwater vehicles are an exciting topic for two reasons. First there are many interesting real-world applications for such systems. Effective autonomous under water vehicles would allow or facilitate exploration, salvage, search and rescue, and scientific studies in deep ocean areas. Second, the highly dynamic and noisy nature of underwater environment makes the problem a difficult one. Combined with the noise and dynamics of the environment are the additional problems of a possible lack of reference points and limited communications due to the water itself.

3. Autosub
A robot submarine expedition under the Antarctic sea ice has discovered a major food reserve in the Southern Ocean. The findings, show a dense band of the, took the revolutionary £5 million Autosub, one of the most advanced underwater probes ever.

Chapter 8 : ADVANTAGES

1. Under water movement in all possible directions i.e. right, left, forward, reverse, Up and down.
2. If camera attached can view the under water circumstances.
3. Least cost.
4. Movement of robot is remotely controlled.
5. It could remain beneath water for a long time which is difficult for human being.


1. Power supply to the motors is through wires.
2. Camera video signal shall be taken through wires (if used).
3. DC motor are used for underwater operation so may undergo electrolysis and rusting.


1. We can add water proof cameras to see deep underneath world.
2. This camera can be powered by focusing light to light on the dark surfaces.
3. Receiver and Driver circuit can be made compact and mounted on the main body itself and can be powered using battery supply.
4. Sensor could be mounted on to the body to study the properties of water.

Thursday, 3 June 2010

PIC project download

12 CH iR.rar
12C509_logicgate replacement.rar
16f 84 pic servo controller 8 servo.rar
16f84 one oclock battery charger.rar
16f84 Digital Altimeter using Motorola MPXS4100.rar
16f84 weeder frequency counter.rar
16f877 brushless motor control made easy.rar
3 digit UpDown 16f84.rar
4 Channels Temperatures Monitor.rar
50mhz caunter.rar
A Microcontroller System.rar
Audio Spectrum Monitor.rar
Audio Spectrum radioMonitor.rar
Brenner8 USB PIC Programmer.rar
Car Fuel Display 16f84.rar
Control Remoto10 canales.rar
Digital PC Oscilloscope.rar
Digital power supply.rar
Electronics -- 10xHz Precision Clock Generator.rar
Hi-Fi Preamp pic16f877.rar
IR On-Off.rar
Ir on off.rar
K128 USB PIC Programmer.rar
LCD based PIC Register Monitor.rar
LCFMetr s PIC.rar
Mause Controlled Pulse Power Supply.rar
PIC - MMC (Multi Media Card) Flash Memory Extension.rar
PIC 16F84 + IR + LCD + RS232.rar
PIC 16F877 16F874 Development Board.rar
PIC Power Meter.rar
PIC Power Supply.rar
Pic 16F877 CD Rom to CD Player converter.rar
Radio Spectrum Monitor.rar
Serial port example PIC_Hi-Tech_C_PIC16F87x.rar
Super Simple PIC 16x84 Development Board.rar
Termometar Nokia 3310 Lcd.rar
Ultrasonic Range Meter.rar
Universal ( IR ) Remote control tester.rar
Universal IR-Remote Lamp Controller.rar
VGASCARTAudio Automatic Switch.rar
Video DVM.rar
alkol tester.rar
dimmer pic.rar
gsm lcd.rar
pic power.rar
pic ups.rar
single channel triac phase controller for a PIC16x84.rar
small world of prototyping boards pic-avr.rar
swr meter.rar
ulturasonic radar.rar
usb switch.rar
vga testter.rar

AVR project download

5x7 LED dot matrix pong.rar
8051 test board.rar
A small robot board with the AVR.rar
AVR AT90S2313 Development Board.rar
AVR ATmega8 Testboard.rar
AVR Chatboard.rar
AVR ICSP Adapter Par.rar
AVR RS232 interface.rar
AVR Serial LCD using Attiny2313.rar
AVR boards commonly.rar
AVR programmer.rar
Acceleration meter cars.rar
Analog to Digital capabilities of Atmel ATtiny26.rar
Basically the AccelR8.rar
Bluetooth boards developed within the CSE.rar
Control AVR microcontrollers via Visual Basic.rar
Digital Guitar Tuner.rar
Evertool is an AVRISPSTK500-protocol and.rar
FT232 Testboard.rar
Implementation USB into microcontroller Igor Atmel-USB device.rar
M8+LCD1602+LM35 srj.rar
MP3 mega162.rar
Mini DDS direct dijital synthesis.rar
Monster Memory.rar
My first attempt with RF modules.rar
Ponyprog Circuit for ATMEL'S AVR.rar
SMS remote control with 4 relays version.rar
Stepper Motor Driver RS232.rar
Temperature Controller.rar
Timer mit ATmega8.rar
atmel Unipolar Stepper Motor.rar
atmel vu meter.rar
avr saat.rar
avr vertical color genarator.rar
dspio board.rar
e10-g rs232 modem.rar
lcd counter.rar
lcd keys.rar
midi genarator.rar
simpleVGA video adapter.rar
tarih s_cakl_k.rar
telecard reader.rar
uCOS-II AVR-GCC port.rar
usb interface usb _nfred remote contrl.rar
usb swic.rar
yet another AVR programmer.rar

Wednesday, 2 June 2010

Push Technology

Push technology reverses the Internet's content delivery model. Before push, content publishers had to reply upon the end-users own initiative to bring them to a web site or download content. With push technology the publisher can deliver a content directly to the users PC, thus substantially improving the likelihood that the user will view it. Push content can be extremely timely, and delivered fresh several times a day. Information keeps coming to user whatever he asked for it or not. The most common analog for push technology is a TV channel; it keeps sending us stuff whether we care about it or not.

Push was created to alleviate two problems facing users of net. The first problem is information overload. The volume and dynamic nature of content on the internet is a impediment to users, and has become an ease-of -use of issue. Without push applications can be tedious, time consuming, and less than dependable. Users have to manually hunt down information, search out links, and monitor sites and information sources. Push applications and technology building blocks narrow that focus even further and add considerable ease of use. The second problem is that most end-users are restricted to low bandwidth internet connections, such as 33.3 kbps modems, thus making it difficult to receive multimedia content. Push technology provides means to pre-deliver much larger packages of content.

Push technology enables the delivery of multimedia content on the internet through the use of local storage and transparent content downloads. Like a faithful delivery agent, push, often referred to as broadcasting, delivers content directly to user transparently and automatically. It is one of the internet's most promising technologies.

Already a success, push is being used to pump data in the form of news, current affairs and sports etc, to many computers connected to the internet.Updating software is one of the fastest growing uses of push. It is a new and exciting way to manage software update and upgrade hassles. Using the internet today without the aid of a push application can be a tedious, time consuming, and less than dependable. Computer programming is an inexact art, and there is a huge need to quickly and easily get bug fixes, software updates, and even whole new program out to people. Users have to manually hunt down information, search out links, and monitor sites and information sources.


For the end user, the process of receiving push content is quite simple. First, an individual subscribes to a publisher's site or channel by providing the content preferences. The subscriber also sets up a schedule specifying when information should be delivered. Based on the subscriber's schedule, the PC connects to the internet, and the client software notifies the publisher's server that the download can occur. The server collates the content pertaining to the subscriber's profile and downloads it to the subscriber's machine, after which the content is available for the subscriber's viewing


Interestingly enough, from a technical point of view, most push applications are pull and just appear to be 'push' to the user. In fact, a more accurate description of this process would be 'automated pull'.

The web currently requires the user to poll sites for new or updated information. This manual polling and downloading process is referred to as 'pull' technology. From a business point of view, this process provides little information about user, and even little control over what information is acquired. It is the user has to keep track of the location of the information sites, and the user has to continuously search for informational changes - a very time consuming process. The 'push' model alleviates much of this tedium.

Spectrum Pooling

THE success of future wireless systems will depend on the concepts and technology innovations in architecture and in efficient utilization of spectral resources. There will be a substantial need for more bandwidth as wireless applications become more and more sophisticated. This need will not be satisfied by the existing frequency bands being allocated for public mobile radio even with very evolved and efficient transmission techniques. Also wide ranges of potential spectral resources are used only very rarely. In the presented approach that is called spectrum pooling, different spectrum owners (e.g. military, trunked radio etc.) bring their frequency bands into a common pool from which rental users may rent spectrum. Spectrum pooling reflects the need for a completely new way of radio resource management. Interesting aspects of the spectral efficiency gain that is obtained with the deployment of spectrum pooling.

A potential rental system needs to be highly flexible with respect to the spectral shape of the transmitted signal. Spectral ranges that are accessed by licensed users have to be spared from transmission power. OFDM modulation is a candidate for such a system as it is possible to leave a set of subcarriers unmodulated. Thus, providing a flexible spectral shape that fills the spectral gaps without interfering with the licensed users. A schematic example of this method is given in Fig. 1. Furthermore, spectrum pooling systems are not supposed to compete with existing and upcoming 2G and 3G standards. They are rather meant to be a complement in hot spot areas with a high demand for bandwidth (e.g.airports, convention centers etc.). Hence, it is straightforward to apply modified versions of OFDM based wireless LAN standards like IEEE802.11a and HIPERLAN/2.

There are many modifications to consider in order to make wireless LANs capable of spectrum pooling. They range from front end via baseband processing to higher layer issues. One important task when implementing spectrum pooling is the periodic detection of idle subbands of the licensed system delivering a binary allocation vector as shown in Fig. 1. A detailed description of how to perform this in an optimal fashion is given. We propose an approach where any associated mobile terminal of the rental system conducts its own detection. This detection is the first step in a whole protocol sequence that is illustrated in Fig. 2. Having finished the detection cycle, the results are then gathered at the access point as visualized in Fig. 2b). The received information can be processed by the access point which basically means that the individual binary (allocated/deallocated) detection results are logically combined by an OR operation.

Thereafter, a common pool allocation vector which is mandatory for every mobile terminal is broadcast in a last phase as shown in Fig. (2c). It is shown that this distributed technique is more reliable and yields a higher system throughput than only having the access point conduct a spectral detection. However, if the collection of the detection results is realized by sending a MAC layer data packet for each mobile terminal, the signaling overhead will be very high as the number of mobile terminals can be as high as 250 in the considered wireless LAN systems.

Now, one could reduce the number of detecting mobile terminals. Unfortunately, this approach has several drawbacks. The random choice of the detecting rental users would not guarantee an optimal spatial distribution of the detecting mobile terminals. The transmission of these results would still take a lot of time and their correct reception is disturbed by rental users that have accessed their subbands since the last detection cycle. One further problem is the redundancy in the measurement data. Several mobile terminals can encounter the same constellation of licensed user accesses. We investigated techniques like the adaptive tree walk protocol to reduce the amount of measurement data packets but none of them was satisfactory with respect to duration and robustness.


Mobile IP is the IETF proposed standard solution for handling terminal mobility among IP subnets and was designed to allow a host to change its point of attachment transparently to an IP network. Mobile IP works at the network layer, influencing the routing of datagrams, and can easily handle mobility among different media (LAN, WLAN, dial-up links, wireless channels, etc.). Mobile IPv6 is a protocol being developed by the Mobile IP Working Group (abbreviated as MIP WG) of the IETF (Internet Engineering Task Force).

The intention of Mobile IPv6 is to provide a functionality for handling the terminal, or node, mobility between IPv6 subnets. Thus, the protocol was designed to allow a node to change its point of attachment to the IP network such a way that the change does not affect the addressability and reachability of the node. Mobile IP was originally defined for IPv4, before IPv6 existed. MIPv6 is currently becoming a standard due to inherent advantages of IPv6 over IPv4 and will therefore be ready soon for adoption in 3G Mobile networks. Mobile IPv6 is a highly feasible mechanism for implementing static IPv6 addressing for mobile terminals. Mobility signaling and security features (IPsec) are integrated in the IPv6 protocol as header extensions.

The current version of IP (known as version 4 or IPv4) has not changed substantially since RFC 791, which was published in 1981. IPv4 has proven to be robust, and easily implemented and interoperable. It has stood up to the test of scaling an internetwork to a global utility the size of today's Internet. This is a tribute to its initial design.

However, the initial design of IPv4 did not anticipate:
" The recent exponential growth of the Internet and the impending exhaustion of the IPv4 address space
Although the 32-bit address space of IPv4 allows for 4,294,967,296 addresses, previous and current allocation practices limit the number of public IP addresses to a few hundred million. As a result, IPv4 addresses have become relatively scarce, forcing some organizations to use a Network Address Translator (NAT) to map a single public IP address to multiple private IP addresses.
" The growth of the Internet and the ability of Internet backbone routers to maintain large routing tables
Because of the way that IPv4 network IDs have been (and are currently) allocated, there are routinely over 85,000 routes in the routing tables of Internet backbone routers today.
" The need for simpler configuration

Most current IPv4 implementations must be either manually configured or use a stateful address configuration protocol such as Dynamic Host Configuration Protocol (DHCP). With more computers and devices using IP, there is a need for a simpler and more automatic configuration of addresses and other configuration settings that do not rely on the administration of a DHCP infrastructure.

" The requirement for security at the IP level
Private communication over a public medium like the Internet requires cryptographic services that protect the data being sent from being viewed or modified in transit. Although a standard now exists for providing security for IPv4 packets (known as Internet Protocol Security, or IPSec), this standard is optional for IPv4 and proprietary security solutions are prevalent.
" The need for better support for real-time delivery of data-also called quality of service (QoS)

Poly Fuse

Polyfuse is a new standard for circuit protection. It is resettable. Many manufacturers also call it polyswitch or multifuse. Polyfuses are not fuses but polymeric positive temperature co-efficient (PPTC) thermistors.

Current limiting can be accomplished by using resistors , fuses , switches or positive temperature co-efficient devices. Resistors are rarely an acceptable solution because the high power resistors that are usually required are expensive. One-shot fuses can be used, but they might fatigue, and they must be replaced after a fault event. Ceramic PTC devices tends to have high resistance and power dissipation characteristics.

The preferred solution is a PPTC device which has low resistance in normal operation and high resistance when exposed to a fault. Electrical shorts or electrically over-loaded circuits can cause over-current and over temperature damage.

Like traditional fuses , PPTC devices limit the flow of dangerously high current during fault conditions. Unlike traditional fuses, PPTC devices reset after the fault is cleared and the power to the circuit is removed.


Technically, polyfuses are not fuses but polymeric positive temperature co-efficient (PPTC) thermistors. For thermistors characterized as positive temperature co-efficient , the device resistance increases with temperature. These comprise thin sheets of conductive plastic with electrodes attached to either side. The conductive plastic is basically a non-conductive crystalline polymer loaded with a highly conductive carbon to make it conductive. The electrodes ensure even distribution of power throughout the device.

Polyfuses are usually packaged in radial, axial, surface- mount, chip, disk or washer form, these are available in voltage ratings of 30 to 250 volts and current ratings of 20Ma to 100 amps.


1) INITIAL RESISTANCE:- The resistance of the device as received from the factory of manufacturing.
2) OPERATING VOLTAGE:- The maximum voltage a device can withstand without damage at the rated current.
3) HOLDING CURRENT:- Safe current through the device.
4) TRIP CURRENT:- Where the device interrupts the current.
5) TIME TO TRIP:- The time it takes for the device to trip at a given temperature.
6) TRIPPED STATE:- Transition from the low resistance state to the high resistance state due to an overload.
7) LEAKAGE CURRENT:- A small value of stray current flowing through the device after it has switched to high resistance mode.
8) TRIP CYCLE:- The number of trip cycles (at rated voltage and current) the device sustains without failure.
9) TRIP ENDURANCE:- The duration of time the device sustains its maximum rated voltage in the tripped state without failure.
10) POWER DISSIPATION:- Power dissipated by the device in its tripped state.
11) THERMAL DURATION:- Influence of ambient temperature.
12) HYSTERESIS:- The period between the actual beginning of the signaling of the device to trip and the actual tripping of the device.

Fractal Antennas

There has been an ever-growing demand, in both the military as well as the commercial sectors, for antenna designs that possess the following highly desirable attributes: 1. Compact size 2. Low profile 3. Conformal 4. Multi-band or broadband

There are a variety of approaches that have been developed over the years, which can be utilized to achieve one or more of these design objectives. Recently, the possibility of developing antenna designs that exploit in some way the properties of fractals to achieve these goals, at least in part, has attracted a lot of attention.

The term fractal, which means broken or irregular fragments, was originally coined by Mandelbrot to describe a family of complex shapes that possess an inherent self-similarity or self- affinity in their geometrical structure. The original inspiration for the development of fractal geometry came largely from an in-depth study of the patterns of nature. For instance, fractals have been successfully used to model such complex natural objects as galaxies, cloud boundaries, mountain ranges, coastlines, snowflakes, trees, leaves, ferns, and much more. Since the pioneering work of Mandelbrot and others, a wide variety of applications for fractals continue to be found in many branches of science and engineering. One such area is fractal electrodynamics, in which fractal geometry is combined with electromagnetic theory for the purpose of investigating a new class of radiation, propagation, and scatter problems. One of the most promising areas of fractal-electrodynamics research is in its application to antenna theory and design.

Traditional approaches to the analysis and design of antenna systems have their foundation in Euclidean geometry. There have been considerable amounts of recent interest, however, in the possibility of developing new types of antennas that employ fractal rather than Euclidean geometric concepts in their design. We refer to this new and rapidly growing field of research as fractal antenna engineering. Because fractal geometry is an extension of classical geometry, its recent introduction provides engineers with the unprecedented opportunity to explore a virtually limitless number of previously unavailable configurations for possible use in the development of new and innovative antenna designs. There primarily two active areas of research in fractal antenna engineering. These include: 1.) the study of fractal-shaped antenna elements, and 2.) the use of fractals in the design of antenna arrays. The purpose of this article is to provide an overview of recent developments in the theory and design of fractal antenna elements, as well as fractal antenna arrays. The related area of fractal frequency-selective surfaces will also be considered in this article.


The term "Fractal means linguistically "broken" or "fractured" from the Latin "fractus". Benoit Mandelbrot, a French mathematician, introduced the term about 20 years ago in his book "The Fractal Geometry of Nature". However many of the fractal function go back classic mathematics. Names like G. Cantor (1872), G. Peano (1890), D. Hilbert (1891), Helge von Koch (1904), W. Sierprinski (1916) Gaston Julia (1918) and other personalities played an important role in Mandelbrot's concepts of a new geometry.

Virtual Keyboard

In computer systems, the actual processors, are more likely to become outdated than to actually wear out. But there are parts of a computer system that are more susceptible to wear and tear.As the technology advances, more and more systems are introduced which will look after the user’s comfort. Few years before hard switches were used as keys. Now-a-days soft touch keypads are much popular in the market. These keypads give an elegant look, they give a better feel.They are dust-proof and has got much more life than the other keypads. Thus we see that the new technology always has more benefits and is more user-friendly.

We are presenting here a next generation technology in this area, which is the Adaptable Virtual Keyboard. As the name suggests the virtual keypad has no physical appearance.In the current scenario we use keyboards which have specific size and specific imprints on the keys. The interactivity and usability of keyboards would surely increase if it could display a symbol for the current function associated with the key or if the language of the keyboard could be changed.

Existing System and their Drawbacks:

Microsoft aimed at making the virtual keyboard but the layout and functions of the keyboard cannot be changed. The system uses 3D modelling to detect a keystroke and is processor intensive. Special hardware to project the “qwerty” layout and infrared light which is required in detection undermines the sole objective of reducing hardware components and cost reduction.
Another hardware based keyboard named “Optimus Prime” has inbuilt LCD display on each key and the function of each key can be changed. This is done to increase interactivity but again, having a LCD display in every key makes is costly. The same functionality can be implemented using the Adaptable Virtual Keyboard and macros.
Proposed system:
The proposed system would have an application frontend which would help initialise the keyboard to the new environment.Any image projected/surface can be a reference and a photo of the same is stored in memory as a reference image. This reference image would be segmented. On running the program we would be able to detect any change in this image by comparing it with the original image stored. After detection of the segment where the change occurs, a virtual key press would be initiated by calling a macro or a function using visual basic.The current function of each key would be displayed for user convenience and can be changed according to user preference. The macro associated with each key can be varied easily from the frontend. This would make the keyboard truly adaptable.
The surface needs to be stable and static, preferably planar and not of skin color. This will serve as the reference and on which the user can put a finger to initiate the virtual key press.

This is the basic input device to the system. The camera needs to be focused correctly. The zoom function of the camera would help vary the effective keyboard size.

Detection Software:
This is the heart of the system. It includes functions to:
o Interface the camera
o Interface for configuring and running the software
o Extract image from video and segment it
o Detect segment where image varies using histograms
o Initiate key press by calling a macro

Following are the major advantages of proposed system:
o Opens a whole new door to keyboard based applications.
o Games can make the maximum utilization of the keyboard by displaying only those keys that are used in the game. Even symbols can be displayed instead of the lame alphabets that have to be remembered. (e.g. Instead of remembering ‘A’ as left, ‘D’ as right we can display ‘?’ on any key that is to be used as left. ‘?’ on any key to be used as right and so on…)
o Multilingual support. Since the key-displays are reconfigurable, there is no language barrier any more.
o Touch screen is similar to this implementation, but they do require additional effort and are not ergonomically comfortable. User doesn’t have to raise his arm to the monitor every time to use it.
o Keyboards with any resolution can be built according to user’s choice.


  • PPT (5017-201227-KEYBOARD.ppt)