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Sunday, April 20, 2008

Automatic Energy Meter Reading through Power Line Communication

Automatic Energy Meter Reading through Power Line Communication
This project deals with “Automatic Energy Meter Reading through Power Line Communication”. Presently in India Energy Meter reading is done through nominated officials by visiting the residential and commercial places. This project is proposed to change the existing energy metering by employing the Power line communication technology. Power line carrier communications take place over the same lines that deliver electricity.

This technique involves injecting a high frequency AC carrier into the power line and modulating this carrier with data originating from the remote meter or central station. Power Line Communications - transmits data over an existing high-voltage power line instead of requiring dedicated cabling. (PLC) can thus provide an inexpensive solution for transmitting data in a pre-wired location.
The solution for residential Automatic Meter Reading (AMR) consists of a host computer, a gateway interface and a low-cost Power Line Carrier (PLC) residential meter. LCD display showing the meter readings, date of bill payment and billing details. The system also incorporates a power cut feature, which can be activated when the consumer doesn’t pay the bill within the due date. The system performances become superior to conventional methods. Now this scheme becomes implementing able with advent fast computing devices.

Thursday, April 10, 2008

FPGA Vs DSP and FPGA applications

FPGA Vs DSP and FPGA applications
The DSP is a specialised microprocessor which is limited in performance by the clock rate, and the number of useful operations it can do per clock. In contrast, an FPGA is an uncommitted "sea of gates". The device is programmed by connecting the gates together to form multipliers, registers, adders and so forth. Using the Xilinx Core Generator this can be done at a block-diagram level. Many blocks can be very high level – ranging from a single gate to an FIR or FFT. Their performance is limited by the number of gates they have and the clock rate. Recent FPGAs have included Multipliers especially for performing DSP tasks more efficiently.
When sample rates grow above a few MHz, a DSP has to work very hard to transfer the data without any loss. This is because the processor must use shared resources like memory busses, or even the processor core which can be prevented from taking interrupts for some time. An FPGA on the other hand dedicates logic for receiving the data, so can maintain high rates of I/O.
The DSP can take a standard C program and run it. Most signal processing systems start life as a block diagram of some sort. Actually translating the block diagram to the FPGA may well be simpler than converting it to C code for the DSP.
APPLICATIONS OF FPGA:
Applications of FPGAs include digital signal processing, software-defined radio, aerospace and defense systems, ASIC prototyping, medical imaging, computer vision, speech recognition, cryptography, bioinformatics, computer hardware emulation and a growing range of other areas.
· FPGAs originally began as competitors to CPLDs and competed in a similar space, that of glue logic for PCBs. As their size, capabilities, and speed increased, they began to take over larger and larger functions to the state where some are now marketed as full systems on chips (SOC).
· FPGAs are increasingly used in conventional High Performance Computing applications where computational kernels such as FFT or Convolution are performed on the FPGA instead of a microprocessor. The use of FPGAs for computing tasks is known as reconfigurable computing.
· The current generation of FPGAs can implement around 100 single precision floating point units, all of which can compute a result every single clock cycle. The flexibility of the FPGA allows for even higher performance by trading off precision and range in the number format for an increased number of parallel arithmetic units. This has driven a new type of processing called reconfigurable computing.

FPGA and CPLD

A Field-Programmable Gate Array is a semiconductor device containing programmable logic components called "logic blocks", and programmable interconnects. Field programmable gate arrays combine the architecture of gate arrays with the programmability of Programmable Logic Devices (PLDs). Some of the FPGA real estate is occupied by vendor logic to implement the field programmability feature of the FPGA, and a large portion of the die area is for programmable routing. The number of gates typically available to the user varies from 3,000 to 10,000. An FPGA normally consists of several uncommitted logic blocks in which the design is to be encoded. The logic block consists of some universal gates.
Logic blocks can be programmed to perform the function of basic logic gates such as AND, NAND and XOR, and more complex combinational functions such as decoders, multiplexers (MUX), random-access memories, etc. The connectivity between blocks is programmed via different types of devices, SRAM (Static Random Access Memory) or ant fuse. Logic blocks and interconnects can be programmed by the customer or designer, after the FPGA is manufactured, to implement any logical function-hence the name "programmable”.
The historical roots of FPGAs are in Complex Programmable Logic Devices (CPLDs). CPLD logic gate densities range from the equivalent of several thousand to tens of thousands of logic gates, while FPGAs typically range from tens of thousands to several million. The primary differences between CPLDs and FPGAs are architectural. A CPLD has a somewhat restrictive structure consisting of one or more programmable sum-of-products logic arrays feeding a relatively small number of clocked registers. The result of this is less flexibility, with the advantage of more predictable timing delays and a higher logic-to-interconnect ratio. The FPGA architectures, on the other hand, are dominated by interconnect. This makes them far more flexible to design for.
FPGAs have the capability of partial re-configuration that lets one portion of the device be re-programmed while other portions continue running The Mitrion Virtual Processor from Mitrionics is an example of a reconfigurable soft processor that is implemented on FPGAs.

Tuesday, April 8, 2008

SMS and Microcontroller based Smart Home Controller

SMS and Microcontroller based Smart Home Controller
The objective of this project is to improve the security performance in the house and to control the home appliances through mobile. This project is designed with Microcontroller, Flame sensor, Gas sensor, IR transmitter and receiver, signal conditioning unit, RS 232, and Data cable with mobile.
Flame sensor is the one type of transducer which is used to sense the flame. If any fire happens in the house the flame sensor will detect that one and send the signal to microcontroller through signal conditioning unit. Gas sensor is also one type of transducer which is used to sense the gas leakage in the house. If any gas leakage in the house it will sense that leakage and send the signal to microcontroller to signal conditioning unit.
Infrared transmitter and receiver are fixed in the entrance door. Initially the infrared transmitter transmits the rays to the receiver. If any one crosses the rays it sends the signal to microcontroller through the signal conditioning unit. Similarly the door breaking sensor is fixed in the entrance door. If any person breaks the door, the sensor will detect the vibration and send the signal to microcontroller through signal conditioning unit.
The signal conditioning unit is constructed with operational amplifier which acts as comparator. It receives the signal from all above mentioned transducer and generates the square pulse. Then this square pulse is given to microcontroller. Here the microcontroller may be Atmel or PIC both are flash type reprogrammable microcontroller in which we have already programmed with desired phone number.
The mobile phone is interfaced with microcontroller through data cable and RS 232. RS 232 converts TTL logic to RS 232 logic. If any one transducer is activated due to that corresponding microcontroller sends the related information to the mobile phone. The mobile phone sends this information as SMS to desired phone as per the phone number stored in the microcontroller.

Wednesday, April 2, 2008

Speed control of DC motor using PWM technique and matlab environment

Speed control of DC motor using PWM technique

DC motors are widely used in industrial applications. In this regard controling the speed in wide range is another aspects. For this purpose, here is an abstract of the project

Electrical is the most valuable and precious one for this universe. In this
the motor plays an important role. Hence we want to control the motor for our requirements.

The aim of this project is to control the speed of the DC motor. Generally, DC motors are applicable for effective speed control and high starting torque applications like traction, lift, etc.

Basically DC motor speed control is done by voltage control, armature resistance control and flux control methods. But in this project we are control the speed of the DC motor by Pulse Width Modulation (PWM) technique. From this method we can obtain a smooth speed variation with out reducing the starting torque of the motor.

PWM technique also eliminate harmonics. Matlab tools are availabe for DC machine. By using this, a matlab using simulink of the speed control of motor can be done in a matlab environment and also can be verified by experiments.

Tuesday, April 1, 2008

Matlab exchange Matlab Central

Matlab Central
Already in previous post i described about matlab and related engineering projects and application. Here i would like to share about matlab exchange where the matlab code files, applications related to matlab tool boxes can be freely obtained and also you can share your matlab files and application with this site. For this go to http://www.mathworks.com/ and register for your product update, then you will be the regular user of this.
Matlab central also includes groups, Contests, file exchange, blogs related to matlab
A lot matlab applications on Embedded systems, control systems, Neural networks, fuzzy, genetic algorithms, communications fields and field of your interest can be obtained here. It is purely for matlab communities

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