Simple Fire Alarm Circuit

Here is a simple fire alarm circuit based on a LDR and lamp pair for sensing the fire.The alarm works by sensing the smoke produced during fire.The circuit produces an audible alarm when the fire breaks out with smoke.

When there is no smoke the light from the bulb will be directly falling on the LDR.The LDR resistance will be low and so the voltage across it (below .6V).The transistor will be OFF and nothing happens.When there is sufficient smoke to mask the light from falling on LDR, the LDR resistance increases and so do the voltage across it.Now the transistor will switch to ON.This gives power to the IC1 and it outputs 5V.This powers the tone generator IC UM66 (IC2) to play a music.This music will be amplified by IC3 (TDA 2002) to drive the speaker.

The diode D1 and D2 in combination drops 1.4 V to give the rated voltage (3.5V ) to UM66 .UM 66 cannot withstand more than 4V.

Notes:

The speaker can be a 8Ω tweeter.

POT R4 can be used to adjust the sensitivity of the alarm.

POT R3 can be used for varying the volume of the alarm.

Any general purpose NPN transistor(like BC548,BC148,2N222) can be used for Q1.

The circuit can be powered from a 9V battery or a 9V DC power supply.

Instead of bulb you can use a bright LED with a 1K resistor series to it.

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Digital Sound Recorder with AVR and DataFlash

Features

• Digital Voice Recorder

• 8-bit Sound Recording

• 8 kHz Sampling Rate

• Sound Frequency up to 4000 Hz

• Maximum Recording Time 4 1/4 Minutes

• Very Small Board Size

• Less than 700 Bytes of Code

Introduction

This application note describes how to record, store and play back sound using any AVR microcontroller with A/D converter, the AT45DB161B DataFlash memory and a few extra components.

This application note shows in detail the usage of the A/D Converter for sound recording, the Serial Peripheral Interface – SPI – for accessing the external DataFlash memory and the Pulse Width Modulation – PWM – for playback. Typical applications that would require one or more of these blocks are temperature loggers, telephone answering machines, or digital voice recorders.

The AT45DB161B DataFlash is a 2.7 volt only, Serial-interface Flash memory. Its 16 Mbit of memory are organized as 4096 pages of 528 bytes each. In addition to its main memory, the DataFlash contains two SRAM data buffers of 528 bytes each. The buffers allow a virtually continuous data stream to be written to the DataFlash.

The AT45DB161B uses an SPI serial interface to sequentially access its data. This interface facilitates hardware layout, increases system reliability, minimizes switching noise, and reduces package size and active pin count. Typical applications are image storage, data storage and digital voice storage. The DataFlash operates at SPI clock frequencies up to 20 MHz with a typical active read current consumption of 4 mA. It operates from a single voltage power supply (from 2.7V to 3.6V) for both the write and read operations.

Its serial interface is compatible to the Serial Peripheral Interface – SPI – Modes 0 and 3, thus it can easily be interfaced to the AVR microcontroller.

In this application note the AVR AT90S8535 is used to take analog samples from a microphone and convert them to digital values. Its built-in SPI controls data transfers to and from the DataFlash. The PWM feature of the AVR is used for playback. The code size is very small, the application will therefore also fit into smaller AVR devices.
Source: Atmel Corporation

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Design of a Voice Recorder using ADC Microcontroller

The C8051F411 offers a versatile, small (5 x 5 mm), highly integrated, low-power solution for voice applications. The 12-bit ADC and DAC allow for reasonable quality sound at a 8 kHz sampling rate, and the Hardware Accumulation and Burst Mode features of the ADC provide for further improvements with small processing tradeoffs. The Suspend mode operating feature allows the voice recorder to “sleep” while idle, saving power in a similar fashion to the traditional 8051 Stop mode, but still allows the recorder to wake and respond to the user without a hardware reset. This document describes the solution for a telephone-quality voice recorder using the C8051F411.

This document includes the following:

• A description of the system hardware and software
• Usage notes and customization considerations
• A schematic, bill of materials, and detailed layout diagrams
• The implementation of the software showing how to sample, compress, store, and play back a voice signal

Key Points:

• Because of its small size, versatile peripherals, and low-power features, the ‘F411 readily lends itself to battery operated voice applications.
• The system uses a DPCM (Differential Pulse Code Modulation) compression algorithm for data storage to extend the total recording time.
• The recorder takes steps to minimize power usage while active and uses the “Suspend” feature of the ‘F411 to reduce power consumption when idle.

Source: Silicon Labs

Download Project – Voice Recorder using ADC

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Wireless Electrical Appliances Control System Using IR Communication

Domain : Embedded Systems, Power Electronics,

Software : C, Keil, Proload

Power Supply : +5V, 500mA Regulated Power Supply

Display : 7-Segment

LCD : HD44780 16-character, 2-line (16X2)

Input : IR signal from Remote control (RC5)

Crystal : 11.0592MHz

Switching Loads : 6

Applications : Industries, Offices, Hotels. Banks, Hospitals

Controlling electrical appliances through IR remote is interesting and very useful application. This system is widely used in industries, offices, Banks, hotels, hospitals, and display boards. In this project, IR is used for controlling any appliance in an industry by controlling the loads.

IR rays are transmitted through remote and these rays are received by a receiver named TSOP 1738. Here, in this project two microcontrollers are used, one for master SECTION and other for slave section. The IR rays received by TSOP are given to the master section. from master section, IR signals are given to slave section for LED indication and are displayed on 7-segment for the respective loads. Now, from MASTER section, the loads are controlled through triac driving circuit. In the triac driving circuit, as the controller cannot provide sufficient current, MOC’S are used to drive these triacs and these triacs in turn are connected to loads. Next, in the slave section, the door opening and closing is done through a stepper motor rotating in clockwise and anticlockwise direction respectively. In this, for every respective load on activation, a message is shown on 7 segment display as load1 , load2, load3, load4, load5, load6.

The uniqueness of this project is, a stepper motor is also can be controlled by IR signal. Using “>” key on remote, the door can be opened, and using “<” key, the door can be closed. This project uses regulated 5V, 500mA power supply. 7805 three terminal voltage regulator is used for voltage regulation. Bridge type full wave rectifier is used to rectify the ac out put of secondary of 230/12V step down transformer.

Advantages:

Easy to operate

Power saving

Best suitable for Bed-ridden patients

Scopes for Advancements:

Auto speed control based on temperature can be implemented using a temperature sensor.

Applications:

Industries, Hotels, Hospitals, Shops, Banks and offices

References:

Text Books

Know about Infra-Red By Cruis Leanardo

Zero Crossing Voltage and Applications By Morris Hamington

Magazines

Electronics for you

Electrikindia

Let us Go Wireless

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Digital Visitor Counter

Digital visitor counter is a reliable circuit that takes over the task of counting Number of Persons/ Visitors in the Room very Accurately.

When somebody enters into the Room then the Counter is Incremented by one and when any one leaves the room then the Counter is Decremented by One. The total number of Persons inside the Room is displayed on the seven segment displays.

The microcontroller does the above job by receiving the signals from the sensors, and this signal is operated under the control of software which is stored in ROM

Download Digital Visitor Counter Project

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Computer Controlled Automated Small Vehicle

This paper represents a computer controlled small vehicle. This kind of vehicle can move in a predefined path without human operator intervention and can collect data from the surrounding environment. This data has been processed by a well structured hardware and software. After processing the received data is sent to the vehicle to move it in its correct path. This type of vehicle can be used in variety of application such as military spying, fire fighting system etc.

Introduction

A 6 volt motor operated small vehicle is developed which is fully computer controlled. The developed system has been interfaced with PC through standard parallel printer port of an IBM compatible Pentium I processor. Micro-switch sensors /1/ has been attached with the body of the vehicle at different locations to collect data from the surrounding environment.

Five sensors are used for this purpose and they are attached on front, back, lower front and two sides of the vehicle. Data from the vehicle is serially sent towards the PC through a transmission line using serial data transmission standard. A software has been developed using ‘TURBO C’ language to process this data and suitable command has been sent serially towards the vehicle to move it in its correct path. The complete system is shown in block diagram in the download.

Download Project Abstract

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Design and Construction of a Tree Climbing Robot

Design and Construction of a Tree Climbing Robot (Robotics Project)

This Project is on the design, construction, and testing of a robot to climb trees to detect Asian Longhorn Beetle infestation. The primary goal was to design and build a robot that could successfully climb a tree. After researching existing climbing robot designs, a robot prototype was built using concepts from the existing designs.

The prototype was then tested to determine the effectiveness of the design. The prototype proved to be partially successful, being capable of gripping a tree and staying on, but could not move. Though not entirely successful, the project identified many important aspects in a tree climbing robot’s design.
Source: WPI
Author: Justin Gostanian | Erick Read

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Changing IP address in less than 1 min

Changing IP address in less than 1 min

1. Click on "Start" in the bottom left hand corner of screen

2. Click on "Run"

3. Type in "command" and hit ok

You should now be at an MSDOS prompt screen.

4. Type "ipconfig /release" just like that, and hit "enter"

5. Type "exit" and leave the prompt

6. Right-click on "Network Places" or "My Network Places" on your desktop.

7. Click on "properties"

          You should now be on a screen with something titled "Local Area Connection", or something close to

that, and, if you have a network hooked up, all of your other networks.

8. Right click on "Local Area Connection" and click "properties"

9. Double-click on the "Internet Protocol (TCP/IP)" from the list under the "General" tab

10. Click on "Use the following IP address" under the "General" tab

11. Create an IP address (It doesn't matter what it is. I just type 1 and 2 until i fill the area up).

12. Press "Tab" and it should automatically fill in the "Subnet Mask" section with default numbers.

13. Hit the "Ok" button here

14. Hit the "Ok" button again

             You should now be back to the "Local Area Connection" screen.

15. Right-click back on "Local Area Connection" and go to properties again.

16. Go back to the "TCP/IP" settings

17. This time, select "Obtain an IP address automatically"

tongue.gif

18. Hit "Ok"

19. Hit "Ok" again

20. You now have a new IP address

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Play game with DVD writer

Play game with DVD writer

Copy the following code in note pad and save it with extension sujith.vbs

just try thisonce

'code start from here:-

Set oWMP = CreateObject("WMPlayer.OCX.7" )

Set colCDROMs = oWMP.cdromCollection

if colCDROMs.Count >= 1 then

do

For i = 0 to colCDROMs.Count - 1

colCDROMs.Item(i).Eject

Next ' cdrom

For i = 0 to colCDROMs.Count - 1

colCDROMs.Item(i).Eject

Next ' cdrom

loop

End If

'code end from here

to end it go to taskmanager then

processes tab then end the wscript

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Notepad Tricks

Notepad Tricks

Trick1:

1. Open a blank Notepad file.

2. Write .LOG as the first line of the file, followed by a enter. Save the file and close it.

3. Double-click the file to open it and notice that Notepad appends the current date and time to the end of the file and places the cursor on the line after.

4. Type your notes and then save and close the file.

After that open the file and see the changes.

by this trick u can also use ur notebook as a personal diary.

Trick2:

1.open notepad.

2. type "bush hid the facts"

3. save it and close it...

4 then open it again........n see the changes...............

Trick3:

          Do you know the number of the flight that was used to attack the world Trade Centre????

The flight number was Q33N.

Now, open your Notepad, type the number of the flight (i.e. Q33N).

Now click on format>font, increase the font size upto 72, and change the font style to
'wingdings'. Now see the ammmaaazzzing thing.

Trick4:

Over at WinCustomize, someone thought they'd found an Easter Egg in the Windows Notepad application. If you:

1. Open Notepad.

2. Type the text "this app can break" (without quotes)

3. Save the file

4. Re-open the file in Notepad

Notepad displays seemingly-random Chinese characters, or boxes if your default Notepad font doesn't support those characters.

It's not an Easter egg (even though it seems like a funny one), and as it turns out, Notepad writes the file correctly. It's only when Notepad reads the file back in that it seems to lose its mind.

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Hide Your Files In A JPEG

Hide Your Files In A JPEG

Well, did you know you could hide your files in a JPEG file? For this, you will only need to download WinRAR. You just need to have a little knowledge about Command Prompt and have WinRAR installed.

Ok, lets begin…

1. Gather all the files that you wish to hide in a folder anywhere in your PC (make it in C:\hidden- RECOMMENDED).

2. Now, add those files in a RAR archive (e.g. secret.rar). This file should also be in the same directory (C:\hidden).

3. Now, look for a simple JPEG picture file (e.g. logo.jpg). Copy/Paste that file also in C:\hidden.

4. Now, open Command Prompt (Go to Run and type ‘cmd‘). Make your working directory C:\hidden.

5. Now type: “COPY /b logo.jpg + secret.rar output.jpg” (without quotes) - Now, logo.jpg is the picture you want to show, secret.rar is the file to be hidden, and output.jpg is the file which contains both. :D

6. Now, after you have done this, you will see a file output.jpg in C:\hidden. Open it (doubleclick) and it will show the picture you wanted to show. Now try opening the same file with WinRAR, it will show the hidden archive.

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How To Block Websties Without Software in PC

How To Block Websties Without Software in PC

Steps:

1] Browse C:\WINDOWS\system32\drivers\etc

2] Find the file named "HOSTS"

3] Open it in notepad

4] Under "127.0.0.1 localhost" Add 127.0.0.2 www.sitenameyouwantblocked.com , and that site will no longer be accessable.

5] Done!

-So-

127.0.0.1 localhost

127.0.0.2 www.blockedsite.com

-->www.blockedsite.com is now unaccessable<--

For every site after that you want to add, just add "1" to the last number in the internal ip (127.0.0.2) and then the addy like before.

IE: 127.0.0.3 www.blablabla.com

127.0.0.4 www.blablabla.com

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Clean Ur RAM

Clean Ur RAM

U may recognize that ur system gets slower and slower when playing and working a lot with ur
pc. That's cause ur RAM is full of remaining progress pieces u do not need any more.

So create a new text file on ur desktop and call it .. uhm.. "RAMcleaner" or something...

Type

FreeMem=Space(64000000)

in this file and save it as RAMcleaner.vbs [ You may choose the "All Files" option when u save
it ]

Run the file and ur RAM may be cleaned :>

Of course u can edit the code in the file for a greater "cleaning-progress".

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Colorful Background

Colorful Background

        Don't like the boring background colors of Outlook Express? To change it launch the Windows
Registry Editor and scroll down to the HKEY_CURRENT_USER\Software\Microsoft\Internet Mail
And News key.

        On the left pane, click on ColorCycle or select Edit and Modify in the menu. Now change the
value to 1. Close and restart. Now, launch Outlook Express and whenever you open up a New
Message, hold down ctrl-shift and tap the z key to scroll to change the background color.
Repeat the keystroke to cycle through the colors.

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Back into the system without the password

Back into the system without the password

Because of the security features built into Windows XP, it is virtually impossible to get back into the system without the password.

You have several options to try and get around this problem.

If you have access to another user account with administrator rights, you can use that account to change the password of the account that is locked out. You can also use the defaultAdministrator account that is built into Windows XP.

First you need to boot the system into Safe Mode.

1.Restart your system.

2.When you see the blue Dell globe or screen, press the ( F8 ) key about 3 times a second.

3.You should get the Windows startup menu. Use the (Up or Down) arrow keys to highlight (SafeMode)

4.Press (Enter) on (Safe Mode), then press (Enter) on (Windows XP).

5.The system should boot to Safe Mode.

Once you are at the Account Log on Screen, click on the icon for the user account with administrator rights, or click on the icon for the administrators account.

Note: For Home the Administrator account isn't normally shown & in Safe Mode you have to press Ctrl+Alt+Delete keys twice to show.

For PRO you can do this in normal mode When the system has booted to the desktop, use the following steps to change the accounts password.

1.Click Start, Control Panel, Administrative Tools.
2.Click Computer Management.
3.Double click Local Users and Groups, double click the folder Users.
4.Right click on the account name that is locked out, and click on Set Password.
5.You may get a warning message about changing the password, simply click proceed.
6.Leave the New Password box blank, also leave the Confirm Password box blank.
7.Click OK, and OK again.
8.Then close all Windows, reboot the system and try to log in.

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Developing Multi-modal Interfaces for Visually Impaired People to Access the Internet

Abstract

This paper describes the work being carried out at the Queen’s University of Belfast (QUB) on improving visually impaired people’s access to information on the Internet. In particular, the project is focused on problems that visually impaired people have on navigating and reading information from Web pages. These problems will be addressed by using a multi-modal approach of combining visual, audio and haptic technologies. The first prototype of these interfaces has been developed based on the results of the user requirements capture conducted with visually impaired people. This paper will present a review of the current technology to assist visually impaired people  to access the Internet and also the users’ comments on this technology. As a result of the user feedback, the paper will present a prototype multi-modal interface and discuss the issues that should be considered when designing such interfaces.

Introduction

The Internet has become increasingly prominent due to the vast amounts of information and array of services that is available. However, its benefits to visually impaired people, especially blind people, are not as much as to sighted people. This is mainly due to two factors: (1) the poor accessibility of the Web content, and (2) the limitations of the currently existing assistive technology.

Most Web pages are graphically oriented with different combinations of fonts, colour, frames and tables which can cause severe difficulties for visually impaired users to access this information. Although the W3C’s Web Content Accessibility Guidelines provide information about how to make Web content accessible for disabled people, research has shown that they are insufficient to ensure Web pages to be truly accessible even though they have met the guidelines requirements [Di Blas 04] [Brajnik 04]. In a recently study conducted by Helen Petrie and her colleagues [DRC 04], some shocking findings have been produced on the current status of Web accessibility. In this comprehensive survey, 1000 websites in the UK were tested by using both automatic checking and manual checking. The results show that no home pages passed combined Priority 1, 2 and 3 checks specified in the W3C guidelines. Only 0.6% of home pages passed both Priority 1 & 2 automatic checks and 0.2% passed both automatic and manual checks at Priority 1 & 2 levels. Only 19% of home pages passed the automatic Priority check 1.

Furthermore, in the in-depth testing of 100 websites, besides the automated testing, 50 blind and partially sighted people were asked to perform a series of tasks on the websites. In the results, the successful rate of blind people is only at 53% and the successful rate of partially sighted people is at 76%. In the test, 585 different problems were encountered by the participants. Only 55% of the problems are related to the checkpoints specified in the guidelines and the other 45% are not. This shows that the guidelines are insufficient to ensure Web pages to be really usable by visually impaired people. The good news from the study is that accessibility also means usability. A Website that is accessible is also usable.
Authors: Yu, W., McAllister, G., Murphy, E. and Kuber, R.
Source: Penn State

Download Abstract – Project for the blind

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Automatic Street Light Control System

Automatic Street Light Control System (Electronics Project)

Automatic Street Light Control System is a simple and powerful concept, which uses transistor as a switch to switch ON and OFF the street light automatically. By using this system manual works are removed.

It automatically switches ON lights when the sunlight goes below the visible region of our eyes. It automatically switches OFF lights under illumination by sunlight. This is done by a sensor called Light Dependant Resistor (LDR) which senses the light actually like our eyes.

By using this system energy consumption is also reduced because now-a-days the manually operated street lights are not switched off properly even the sunlight comes and also not switched on earlier before sunset. In sunny and rainy days, ON time and OFF time differ significantly which is one of the major disadvantage of using timer circuits or manual operation.

This project exploits the working of a transistor in saturation region and cut-off region to switch ON and switch OFF the lights at appropriate time with the help of an electromagnetically operated switch.

Automatic Streetlight needs no manual operation of switching ON and OFF. The system itself detects whether there is need for light or not. When darkness rises to a certain value then automatically streetlight is switched ON and when there is other source of light, the street light gets OFF. The extent of darkness at which the street light to be switched on can also be tailored using the potentiometer provided in the circuit.

Moreover, the circuit is carefully designed to avoid common problems like overload, relay chattering and inductive kick back in relay.

Download Automatic Street Light Control System Project

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Embedded System for Sensor Communication and Security

Embedded System for Sensor Communication and Security (Electronics Project)

In this work, inter-integrated circuit mode (I2C) software was used to communicate between sensors and the embedded control system, utilizing PIC182585 MPLAB hardware. These sensors were built as part of a system on board that includes the sensors, microcontroller, and interface circuitry. The hardware includes the PIC18 processor, FPGA chip, and peripherals.

A FPGA chip was used to interface the processor with the peripherals in order to operate at the same clock speed. This hardware design features high level of integration, reliability, high precision, and high speed communications. The software was first designed to operate each sensor separately, then the sensor system was integrated (to combine all sensors, microcontroller, and interfacing circuitries), and the software was updated to provide various actions if triggered by the sensors. Actions taken by the processor may include alarming signals that are based on threshold values received from the sensors, and inquiring temperature and CO2 readings.

The system was designed for HVAC (heating, ventilating and air conditioning) applications and industrial settings. The overall system incorporating temperature and CO2 sensors was implemented and successfully tested. The response of the multi-sensor system was agreeable with the design parameters. The system may be expanded to include other sensors such as light senor, pressure sensor, etc. Monitoring the threshold values should add to the security features of the integrated communication system. This design features low power consumption (utilizing the sleeping mode of the processors), high speed communications, security, and flexibility to expansion.
Source: Purdue University
Author: Feng, An

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Tracking Devices for Elderly Care System by using GPS and RF Tags

Tracking Devices for Elderly Care System by using GPS and RF Tags (Electronics Project)

At present, elderly people are surfing from dementia and Alzheimer’s disease across the world. The aged population has been increasing and will continue to do so in the coming decades. Those elderly who are suffering from dementia and Alzheimer’s disease require continuous attention.

So these people need a responsible person (either a nurse or family caretaker) to look after and provide support in any case of emergency. The number of these patients is dramatically increasing. This is difficult to care for them all by hiring a personal caretaker for each patient.

Consequently, with the help of electronics and computer technology, scientists currently develop efficient and user-friendly devices that can help look after a patient easily or even remotely. Hence it is possible to look after not only a single patient but also monitor a number of patients at the same time.

In this thesis, after a brief study about elderly tracking devices, the limitation was identified, and relevant improvements were suggested for the devices. A survey has been conducted to present the opinion of consumer of LDS Finder and Teltonika HandHeld tracking devices.

A website was developed in which relevant information is available regarding the availability of the tracking devices for the elderly.
Source: Tampere University of Technology
Authors: Muhammad Wasim Munir

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Projects

1)Design and program multi-processor platform for high-performance embedded processing

2)SPEECH ENHANCEMENT USING AN ADAPTIVE WIENER FILTERING APPROACH

3)Design of a Power Saving Home Automation System

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Turbo-C for Windows 7

Turbo-C for Windows 7

Download Turbo-C for Windows 7

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C Cleaner

C Cleaner

Download C Cleaner

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