Microcontroller Based Projects list Three phase Induction motor Control Using Microcontroller * Multi Task Industrial Timer Using Microcontroller* M

Microcontroller Based Projects list

Three phase Induction motor Control Using Microcontroller

* Multi Task Industrial Timer Using Microcontroller* Multi Task Industrial Timer Using Microcontroller
* Digital Clock Using AT89C2051 Microcontroller
* Laser Based Automatic Visitor Counter cum Room Light Controller
* Biomedical Data Transmission Using Wireless Network
* Digital Clock Using AT89C51 Microcontroller
* Industrial Automation using computer’s parallel port (Visual Basic)
* Digital Day And Date Display Using Microcontroller
* Digital Countdown Timer Using Microcontroller
* Digital 74 Series IC Tester
* Digital Visitor Counter Using Microcontroller
* DS1620 Based Temperature Controller Using Microcontroller
* DS1820 Based High Precision Temperature Indicator Using Microcontroller
* Electronic Voting Machine Using Microcontroller
* Electronics Components Tester Using Microcontroller
* Biometric Security System (Finger Print Based)
* Ultrasonic Distance Meter using microcontroller
* Mobile Controlled Robot Machine
* Telephone Controlled Device Switching Using Microcontroller
* Infrared Interrupt counters Using Microcontroller
* 6 Line and one fan Infrared Remote Switch Using Microcontroller
* Infrared Remote Switch Using Microcontroller
* Interactive Voice Response System (IVRS)
* Line Following Robot Using Microcontroller
* Microcontroller Based Telephone Caller ID
* Microcontroller Based Digital Clock with Alarm
* Password Based Digital code Lock Using Microcontroller
* Multi function Running Lights Using Microcontroller
* Parallel Telephone instrument with secured privacy Using Microcontroller
* Computer to microcontroller communication (Wireless) Using Microcontroller
* PC BASED DATA LOGGER Using Microcontroller and Visual Basic
* Computer Based Digital IC Tester
* GPS
* PC Controlled Robot Machine
* Control Ur PC by remote Control
* Simcard Based Prepaid Energy Meter Using Microcontroller
* Industrial Automation and message transmission using internet
* Digital Clock with Remote controlled time settings Using Microcontroller
* Electric Energy Meter Reading Through Wireless
* Wireless Controlled Robot Machine
* RFID Based Attendance System
* RFID Based Security System
* Data Transmission Through wireless network
* Sending SMS To Landline Telephone Using Microcontroller
* Wireless Data Communication (AT89S52)
* Efficient Solar Energy generation using movable solar panel
* Motor controller using Telephone
* Industrial control using Telephone
* Temperature controlled Colling Fan Using Microcontroller
* Time Operated Electrical Appliances Controlling System
* Traffic signal Controller Using Microcontroller
* Two Line Intercom Using Microcontroller
* Microcontroller-based LED Light Chaser
* Microcontroller-based Temperature Indicator
* PC-based Wireless Stepper Motor Control
* Microcontroller-based Ring Tone Player
* Solar LED Lighting System
* Clap-operated Appliance Control
* Microcontroller-based Speedometer-Cum-Odometer
* PC-Based Mobile Robot for Navigation
* Solar Electric Fence
* Four-Channel Analogue-to-Digital Converter
* Microcontroller-based Temperature Meter
* Kapalbhati Pranayama Timer
* Microcontroller-Based Inductance Meter
* Cellphone-Operated Land Rover
* Presentable Timer Using Secret-Coded Punched Card
* Rank Display System for Race and Quiz Competitions
* Remote-Controlled Toy Boat
* Microcontroller-Based Heart-Rate Meter
* Multiple Devices Switching Through Parallel Port
* Microcontroller-Based Capacitance Meter
* Token Number Display
* Microcontroller-Based DC Motor Speed Controller
* MICROCONTROLLER-BASED TEMPERATURE INDICATOR
* Buzzer Controller for 8-Team Quiz Contests
* Microcontroller-based Ultrasonic Distance Meter
* Microcontroller-based Tachometer
* Temperature Indicator-cum-Controller
* Microcontroller-Based Alarm Clock

* Simple PC-Based Digital Sound-Level Meter
* Low-Cost Versatile Timer Using AT89C2051
* Parallel-Port Interfacing and Programming Aid
* Digital Heart-Beat Counter
* Secured Room Access System
* Digital Voltmeter
* Microcontroller-based Graphics Display
* Microcontroller-based Industrial Timer
* Standalone Digital Clock
* PC-based Dual DC Motor Controller
* Wireless Messaging Via Mobile/Landline Phone
* Microcontroller-based Infrared Tracking Robot
* Remote-Controlled Real-Time Clock with Device Controller
* Auto Controller for Petrol-Run Power Generator
* Design Your Own Infrared Remote
* PIC16F84-based Digital Thermometer
* Water-level Controller-cum-motor Protector
* Digital Phase Selector
* Microcontroller-based Bidirectional Visitor Counter
* Microcontroller-based Automatic Flush System
* Two-Channel PC-based Oscilloscope
* Quiz Buzzer
* Stepper Motor Controller Using AT89C51
* Beverage Vending Machine Controller
* Digital Thermometer-cum-Controller
* Digital Weight Accumulator
* Remotely Programmable RTC-Interfaced Microcontroller for Multiple Device Control
* Auto Switch for TV
* Microcontroller-based Code Lock
* Microcontroller-based Triggering Circuit for SCR Phase Control
* Parallel-Port Testing and Programming Aid
* Fastest-Finger-First Using Microcontroller
* Remote-Controlled Land Rover—A DIY Robotic Project
* 3D Surround Sound System
* AVR Microcontroller-Based Clock
* Automatic Rain Timer
* Power Factor Correction
* AT89C2051-Based Countdown Timer
* PC-Based Remote-Controlled Stepper Motor
* Low-Cost LCD Frequency Meter
* PC-Based Transistor-Lead Identifier
* A Simple Directional Detector/Counter
* Using AVR Microcontroller for Projects—Part 3 of 3
* Speed Checker for Highways (2005)
* Using AVR Microcontroller for Projects—Part 2 of 3
* Automatic 3-Phase Induction Motor Starter
* Using AVR Microcontrollers for Projects—Part 1 of 3
* Noise-Muting FM Receiver
* Digital Stopwatch
* Remote-Controlled Stepper Motor
* Computerized Electrical Equipment Control
* Manual AT89C51 Programmer
* Medium-Power Low-Cost Inverter
* Programmable Timer Based on AT90S4433 AVR
* Low-Cost Energy Meter Using ADE7757
* Two-Wheeler Security System
* Auto Changeover to Generator on Mains Failure—Part II
* PC-based Scrolling Message Display
* Auto Changeover to Generator on Mains Failure—Part I
* Device Control through PC’s Parallel Port Using Visual Basic
* Remote-Controlled Digital Audio Processor
* Microcontroller-based Real-time Clock
* Standalone Scrolling Display Using AT90S8515 AVR
* Moving Message Over Dot-Matrix Display(2004)
* Ultrasonic Lamp-Brightness Controller
* Digital Combination Lock
* Safety Guard for the Blind
* Microprocessor-Based Home Security System
* Stepper Motor Control Using 89C51 Microcontroller
* Dynamic Temperature Indicator and Controller
* Voice Recording and Playback Using APR9600 Chip
* Load Protector with Remote Switching Facility
* PIC16F84-Based Coded Device Switching System
* Remote-Controlled Sophisticated Electronic Code Lock
* Temperature Indicator Using AT89C52
* Device Switching Using Password
* Laser-Based Communication Link
* Programmer for 89C51/89C52/89C2051 Microcontrollers
* A Bidirectional Visitors Counter
* Digital Clock Using Discrete ICs
* Lift Overload Prevented
* Sound-Operated On/Off Switch
* Digital Water-Level Indicator Cum Pump Controller
* PC-Based Data Logger
* Automatic Water-Level Controller
* Microcontroller-Based Call Indicator
* Controlling a 7-Segment Display Using PC’s Parallel Port(2003)
* Economical UPS for Cordless Phones
* Binary-To-Hexadecimal Decoder
* Proportional Load Control Using PC
* Multifactor Emergency Light
* Fluid Level with Indicator
* Microcontroller-Based School Timer
* Telephone Remote Control
* Auto-Control for 3-Phase Motors
* Programmable Melody Generator -Part II

(RRB) Railway Recruitment Board Exam - 2008 Solved Paper Question paper 1. When a ray of light passes from an optically denser medium to a rarer medi

(RRB) Railway Recruitment Board Exam - 2008 Solved Paper Question paper

1. When a ray of light passes from an optically denser medium to a rarer medium, it
(a) Remains undeviated (b) Bends towards normal
(c) Bends away from normal (d) None of these
2.Who is the author of "Anandmath" ?
(a) Rabindranath Tagore (b) Bankim chandra Chattopadhyaya
(c) Sarojini Nayadu (d) Jyotiba Phule
3. Thimpu is the capital of -
(a) Nepal (b) Bhutan
(c) Thailand (d) Myanmar
4. The time period of a seconds pendulum is
(a) 1 second (b) 4 seconds
(c) 3 seconds (d) 2 seconds
5. The nuclear fuel in the sun is
(a) Helium (b) Uranium
(c) Hydrogen (d) Oxygen
6. The second’s hand of a watch is 2 cm long. The velocity of its tip is
(a) 0.21 cm/sec. (b) 2.1 cm/sec.
(c) 21 cm/sec. (d) None of these
7. In diesel engine, ignition is caused by
(a) Spark (b) Automatic starter
(c) Compression (d) Friction
8. The mass-energy equivalence, relationship E = mc2 was propounded by
(a) Max Plank (b) Einstein
(c) Newton (d) Hertz
9. The filament of bulb is made of
(a) Tungsten (b) Iron
(c) Nichrome (d) Carbon
10. Anti-knocking can be lessened by
(a) Iso Octane (b) N Heptane
(c) TEL (d) Benzene
11. In which of the following oxidation shows a positive oxidation state.
(a) CO (b) N2O
(c) NO (d) F2O
12. Which of the following is used in photography?
(a) Silver Bromide (b) Sodium Bromide
(c) Potassium Chloride (d) Sodium Sulphate
13. Which of the following is used in accumulator cell?
(a) Copper (b) Iron
(c) Lead (d) Zinc
14. Choose the wrong statement :
(a) Single magnetic poles can exist
(b) Magnetic poles are always of equal strength
(c) Like poles repel each other
(d) None of these
15. Laws of electrolysis are given by:
(a) Farady (b) Maxwell
(c) Lenz (d) Bohr
16. Flemings left hand rule is used to fine out:
(a) Direction of magnetic field due to flow of current
(b) Direction of induced current due to effect of magnetic field
(c) Direction of motion of a current carrying conductor in magnetic field
(d) None of these
17. The pH of a neutral solution at 250C is :
(a) 0 (b) 1.0
(c) 7.0 (d) 1.4
18. The raw material used for the manufacture of Portland cement is :
(a) Limestone and clay (b) Alumina, clay and gypsum
(c) Gypsum and limestone (d) Gypsum and clay19. CaOCI2 is the chemical formula for a compound commonly known as :(a) Soda Ash (b) Lime
(c) Bleaching Powder (d) Plaster of Paris
20. The glass used for making laboratory apparatus is :(a) Pyrex glass (b) Hard glass
(c) Soft glass (d) Safety glass
21. The iron produced in blast furnace is :
(a) Pig iron (b) Wrought iron
(c) Stainless steel (d) Steel
22. Formation is a 40% solution of :
(a) Methanol (b) Methenal
(c) Methanoic acid (d) None of these
23. Which of the following is not an ore of aluminium :
(a) Cryolite (b) Feldspar
(c) Bauxite (d) Azurite
24. Rhombic monoclinic and plastic sulphur are:
(a) Isomers (b) Isotopes
(c) Allotropes (d) Hydrides of sulphur25. The alkaline hydrolysis of oils or fats gives soap and :
(a) Glycerol (b) Ethenol
(c) Glycol (d) Ethanoic acid
26. The sight of a delicious food usually makes month watery. It is a :
(a) Hormonal response (b) Neural response
(c) Optic response (d) Olfactory response
27. Nitrogen fixing bacteria are normally found in :
(a) Parasitic plants (b) Epiphytic plants
(c) Leguminous plants (d) Aquatic plants
28. Powdery mildew of wheat is caused by:
(a) Bacteria (b) Virus
(c) Fungi (d) Protozoans
29. Septic sore throat is caused by :
(a) Bacteria (b) Virus
(c) Fungi (d) Protozoans
30. A person of blood group AB can give blood to :
(a) ‘A’ and ‘B’ (b) Only ‘AB’
(c) ‘A’, ‘B’ and ‘O’ (d) All of these
31. Cell activities are controlled by :
(a) Chloroplast (b) Nitochondria
(c) Cytoplasm (d) Nucleus
32. Which of the following helps eye to adjust the focal length of the eye lens :
(a) Cornea (b) Conjunctiva
(c) Ciliary body (d) Iris
33. When pollen of a flower is transferred to the stigma of the same plant, pollination type is referred to as :
(a) Autogamy (b) Allogamy
(c) Xenogamy (d) Geitonogamy
34. Respiration is a :
(a) Catabolic process (b) Anabolic process
(c) Both of these (d) None of these
35. The structural and functional unit of kidneys are :
(a) Neurons (b) Nephrons
(c) Medula (d) None of these
36. Which of the following enzymes is generally nor present in adult human :
(a) Renin (b) Pepsin
(c) Trypsin (d) Amylopsin
37. The part of the plant which is responsible for carrying water and solutes from roots to various parts of plants is :
(a) Phloem (b) Xylem
(c) Duodenum (d) Sclercids
38. ‘Widal test’ is used for susceptibility of :
(a) Malaria (b) Typhoid
(c) Cholera (d) Yellow fever
39. Exchange of gases in plants takes place through :
(a) Stomata (b) Lenticels
(c) Cuticle (d) All of these
40. ‘Lieutenant’ in army is equivalent to following rank in navy :
(a) Lieutenant (b) Sub Lieutanant
(c) Lieutenant Commander (d) None of these
41. Pankaj Advani is associated with :
(a) Snooker (b) Golf
(c) Shooting (d) Archery
42. Which city in the world is known as the forbidden city :
(a) Aberdeen (b) Jerusalem
(c) Mecca (d) Lhasa
43. Rajeev Gandhi Khel Ratna Award carries a sum of :
(a) Rs. 3 lakns (b) Rs. 5 lakhs
(c) Rs. 1 lakh (d) Rs. 7 lakhs
44. Who is known as ‘Nightingale of India’ :
(a) Asha Bhonsle (b) Begum Akhtar
(c) Sarojini Naidu (d) Vijaylaxmi Pandit
45. Which one of the following is not included in the UNESCO’s list of world heritage site :
(a) Kaziranga National Park (b) Qutab Minar
(c) Champaner Pavagarh (d) None of these
46. Which of the following is not an electric resistant?
(a) Lead (b) Ebonite
(c) Charcoal (d) Lac
47. Which of the following is a complementary colour?
(a) Blue (b) Yellow
(c) Magenta (d) Yellow and Magenta
48. The velocity of sound increases in air by ……… for every degree Celsius increase of temperature.
(a) 60 m/sec. (b) 0.61 m/sec.
(c) 60 ft/sec. (d) 0.61 km/sec.
49. Henry is a unit of
(a) Capacity (b) Magnetic field
(c) Inductance (d) Frequency
50. The velocity of rotation of Earth is
(a) 28 km/min (b) 30 km/min
(c) 25 km/min (d) 39.5 km/min
51. What is Hubble?
(a) Warship (b) Star
(c) Telescope (d) Missile
52. Which acid is normally found in lemon and grape fruits?
(a) Citric acid (b) Tartaric acid
(c) Ascorbic acid (d) Lactic acid
53. At which temperature Fahrenheit and Celsius show same reading?
(a) -400 (b) 00
(c) -574.250 (d) 2730
54. Limestone is metamorphosed to form
(a) Graphite (b) Quartz
(c) Granite (d) Marble
55. Rift valley is formed by
(a) Earthquake (b) Folding
(c) Faulting (d) All of these
56. If a piece of ice at 00C is mixed with water at 00C, then
(a) Whole ice melts (b) Some ice melts
(c) No ice melts (d) Temperature decreases
57. Mettur Dam is built on the river
(a) Krishna (b) Cauvery
(c) Narmada (d) Mahanadi
58. Mahendra Giri peak is situated in the
(a) Eastern Ghats (b) Western Ghats
(c) Shiwaliks (d) Vindhyachal
59. In what time a sum will double itself at 20% per annum rate of interest?
(a) 2 years (b) 3 years
(c) 4 years (d) 5 years
60. The famous Dilwara Temple is situated in
(a) Madhya Pradesh (b) Maharashtra
(c) Gujarat (d) Rajasthan
61. Pneumonia affects
(a) Lungs (b) Tongue
(c) Liver (d) Kidney
62. The chemical name of Vitamin A is
(a) Retinol (b) Jhiamin
(c) Biotic (d) Riboflavin
63. A 130m long train crosses a bridge in 30 seconds at 45 kmph. The length of the bridge is
(a) 200m (b) 225m
(c) 245m (d) 250m
64. By selling an article at some price a person gains 10%. If the article is sold at twice of the price, the gain percent will be
(a) 20% (b) 60%
(c) 100% (d) 120%
65. Atoms are electrically charged as
(a) Positive (b) Negative
(c) Bi-positive (d) Neutral
66. Ionic bond exists in
(a) Kcl (b) H2O
(c) NH3 (d) Cl3
67. Which force is required to increase the momentum of an object to 40 kg m/s in 5 seconds?
(a) 2N (b) 4N
(c) 8N (d) 10N
68. The river that does not form delta is
(a) Mahanadi (b) Tapti
(c) Krishna (d) Cauvery
69. The ratio of the redius and height of a cone is 5 : 12, respectively. Its volume is 23147cc. Find its slant height.
(a) 13cm (b) 14cm
(c) 17cm (d) 26cm
70. 27 students took part in a debate of a college. What is the probability that at least 3 of them have their birth days in the same month?
(a) 3/27 (b) 3/12
(c) 12 (d) 1
71. Who was the first winner of Dada Saheb Phalke Award?
(a) B.N.Sarkar (b) Prithvi Raj Kapoor
(c) Devika Rani (d) Kanan Devi
72. How many members are nominated by the President in the Rajya Sabha?
(a) 12 (b) 15
(c) 10 (d) 20
73. Who was the founder of Brahmo Samaj?
(a) Raja Rammohan Roy (b) Aurobindo Ghosh
(c) Vivekanand (d) Dyanand Saraswati
74. The Parliamentary System in India has been taken from
(a) America (b) Britain
(c) Australia (d) Ireland
75. The electric supply in India was first started in
(a) Kolkata (b) Chennai
(c) Mumbai (d) Darjeeling
76. Bhatnagar Prize is given in the field of
(a) Peace (b) Music and dance
(c) Science & technology (d) Fine arts
77. Who discovered the solar system?
(a) Copernicus (b) Kepler
(c) Aryabhatta (d) Newton
78. The Nobel Prize in Economics was started in
(a) 1901 (b) 1936
(c) 1957 (d) 1967
79. In India, the second largest in
(a) Bengali (b) Urdu
(c) Telugu (d) Marathi
80. The first Asian Games were held in
(a) Manila (b) Tokyo
(c) Jakarta (d) New Delhi
81. The Islam was established in
(a) 7th A.D. (b) 5th A.D.
(c) 3rd B.C. (d) 5th B.C.
82. The Olympic Games 2012 will be held in
(a) Moscow (b) Paris
(c) New York (d) London
83. The main factor of air pollution is
(a) Lead (b) Copper
(c) Zinc (d) Gold
84. The bauxite ore is found in
(a) Musabani (b) Karnapura
(c) Koderma (d) Palamu
85. The first fertilizer plant in India was established in
(a) Trombay (b) Nangal
(c) Alwaye (d) Sindri
86. Which of the following had strong navy?
(a) Bahmani (b) Chalukya
(c) Chola (d) Rashtrakuta
87. The last king of Maurya Dynastry was
(a) Brihdarth (b) Kunal
(c) Samprati (d) Salishuk
88. How will the image formed by a convex lens be affected if the central part of the lens is covered by black paper?
(a) Remaining part of the lens will form no image
(b) The central position of the image is absent
(c) There will be no effect
(d) The full image will be formed with lessened brightness
89. The force between two parallel wires conducting current is used to define
(a) Ampere (b) Coulomb
(c) Volt (d) Newton
90. A body is thrown vertically upward and it reaches 10m high. Find the velocity with which the body was thrown? (g = 9.8 m/s)
(a) 10 m/sec. (b) 18 m/sec.
(c) 14 m/sec. (d) 7 m/sec.
91. The buoyancy depends on the
(a) Depth of the fluid (b) Density of the fluid
(c) Volume of the fluid (d) Weight of the fluid
ANSWERS
1. (c) 2. (b) 3. (b) 4. (d) 5. (c) 6. (a) 7. (c) 8. (b) 9. (a) 10. (a) 11. (d) 12. (a)
13. (c) 14. (a) 15. (a) 16. (c) 17. (c) 18. (b) 19. (c) 20. (a) 21. (a) 22. (b) 23. (d)
24. (c) 25. (a) 26. (d) 27. (c) 28. (c) 29. (a & b) 30. (b) 31. (d) 32. (c) 33. (a) 34. (a)
35. (b) 36. (a) 37. (b) 38. (b) 39. (d) 40. (b) 41. (a) 42. (d) 43. (b) 44. (c) 45. (d) 46. (a)
47. (d) 48. (b) 49. (c) 50. (a) 51. (c) 52. (a) 53. (a) 54. (d) 55. (c) 56. (c) 57. (b) 58. (a)
59. (d) 60. (d) 61. (a) 62. (a) 63. (c) 64. (d) 65. (d) 66. (a) 67. (c) 68. (b) 69. (a) 70. (c)
71. (c) 72. (a) 73. (a) 74. (b) 75. (d) 76. (c) 77. (a) 78. (d) 79. (c) 80. (d) 81. (a) 82. (d)
83. (a) 84. (d) 85. (d) 86. (c) 87. (a) 88. (d) 89. (a) 90. (c) 91. (b)

GSM Based Home Security System -abstract,report GSM Based Home Security System Abstract Home security has been a major issue where crime is increas

GSM Based Home Security System

Abstract

Home security has been a major issue where crime is increasing and everybody wants to take proper measures to prevent intrusion. In addition there was a need to automate home so that user can take advantage of the technological advancement in such a way that a person getting off the office does not get melted with the hot climate.

Introduction

The project is aimed at developing the security of Home against Intruders , Gas Leak and Fire . In any of the above three cases any one met while you are out of your home than the device sends SMS to the emergency no provided to it.

The report consists of a background into the area of 8051 microcontroller and mobile communication, how they are interfaced to each other and AT (Attention) commands set used in communication.

HARDWARE USED

1. AT command supporting GSM mobile phone.

2. 89S52 Microcontroller

3. Max 232 IC.

4. Relays

5. Relay driver IC ULN 2803

6. Voltage regulator 7805.

7. Diode IN4007

8. GSM Phone

9. LPG Gas Sensor

SOFTWARE USED

1. Keil u-Vision 3.0

Keil Software is used provide you with software development tools for 8051 based microcontrollers. With the Keil tools, you can generate embedded applications for virtually every 8051 derivative. The supported microcontrollers are listed in the µ-vision

2. PRO51 Programmer Software

THEORY OF OPERATION

In this project we interfaced 8051 microcontroller with Motorola’s C168 GSM mobile phone to decode the received message and do the required action. The protocol used for the communication between the two is AT command.

The microcontroller pulls the SMS received by phone, decode it, recognizes the

Mobile no. and then switches on the relays attached to its port to control the appliances. After successful operation, controller sends back the acknowledgement to the user’s mobile through SMS.

AT-Command set

The following section describes the AT-Command set. The commands can be tried out by connecting a GSM modem to one of the PC’s COM ports. Type in the test-command, adding CR + LF (Carriage return + Line feed = \r\n) before executing. Table gives an overview of the implemented AT-Commands in this application. The use of the commands is described in the later sections.

AT-Command set overview

Command	Description
AT	Check if serial interface and GSM modem is working.
ATE0	Turn echo off, less traffic on serial line.
AT+CNMI	Display of new incoming SMS.
AT+CPMS	Selection of SMS memory.
AT+CMGF	SMS string format, how they are compressed.
AT+CMGR	Read new message from a given memory location.
AT+CMGS	Send message to a given recipient.
AT+CMGD	Delete message.

A BRIEF INTRODUCTION TO 8051 MICROCONTROLLER:

When we have to learn about a new computer we have to familiarize about the machine capability we are using, and we can do it by studying the internal hardware design (devices architecture), and also to know about the size, number and the size of the registers.

A microcontroller is a single chip that contains the processor (the CPU), non-volatile memory for the program (ROM or flash), volatile memory for input and output (RAM), a clock and an I/O control unit. Also called a "computer on a chip," billions of microcontroller units (MCUs) are embedded each year in a myriad of products from toys to appliances to automobiles. For example, a single vehicle can use 70 or more microcontrollers. The following picture describes a general block diagram of microcontroller.

89s52: The AT89S52 is a low-power, high-performance CMOS 8-bit microcontroller with 8K bytes of in-system programmable Flash memory. The device is manufactured using Atmel’s high-density nonvolatile memory technology and is compatible with the industry-standard 80C51 instruction set and pinout. The on-chip Flash allows the program memory to be reprogrammed in-system or by a conventional nonvolatile memory pro-grammer. By combining a versatile 8-bit CPU with in-system programmable Flash on a monolithic chip, the Atmel AT89S52 is a powerful microcontroller, which provides a highly flexible and cost-effective solution to many, embedded control applications. The AT89S52 provides the following standard features: 8K bytes of Flash, 256 bytes of RAM, 32 I/O lines, Watchdog timer, two data pointers, three 16-bit timer/counters, a six-vector two-level interrupt architecture, a full duplex serial port, on-chip oscillator, and clock circuitry. In addition, the AT89S52 is designed with static logic for operation down to zero frequency 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 continue functioning. The Power-down mode saves the RAM con-tents but freezes the oscillator, disabling all other chip functions until the next interrupt

The hardware is driven by a set of program instructions, or software. Once familiar with hardware and software, the user can then apply the microcontroller to the problems easily.

The pin diagram of the 8051 shows all of the input/output pins unique to microcontrollers:

The following are some of the capabilities of 8051 microcontroller.

ü Internal ROM and RAM

ü I/O ports with programmable pins

ü Timers and counters

ü Serial data communication

The 8051 architecture consists of these specific features:

§ 16 bit PC &data pointer (DPTR)

§ 8 bit program status word (PSW)

§ 8 bit stack pointer (SP)

§ Internal ROM 4k

§ Internal RAM of 128 bytes.

§ 4 register banks, each containing 8 registers

§ 80 bits of general purpose data memory

§ 32 input/output pins arranged as four 8 bit ports: P0-P3

§ Two 16 bit timer/counters: T0-T1

§ Two external and three internal interrupt sources Oscillator and clock circuits.

BLOCK DIAGRAM:

8051

Level

Converter

SMS

IR

Sensor

Fire

Sensor

LPG Gas

Sensor

El Cheapo - A Really Simple Power Amplifier Introduction Based on information supplied by a reader, I have learned that my recollection of the El Che

Introduction

Based on information supplied by a reader, I have learned that my recollection of the El Cheapo design was rather badly flawed. It seems I had mixed up recollections, and merged a couple of completely different designs into one - none of which resemble the original El Cheapo in any way.

Originally designed by R.R. Moore and published in Audio Magazine (November 1964 edition), the design is presented more for historical interest than as a recommended design. While not a bad amp by the standards of the day, it will be found lacking if compared to any more modern offerings. This will apply even using the latest transistors, because the amp has very limited open loop gain. To some people, this is seen as a benefit rather than a limitation, but it does mean that low-level non-linear distortion will be higher than you are used to.

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Description

The amp was called "El Cheapo 2-30", and was rated at a maximum of 30W per channel into 16 Ohms. It used a single regulated power supply and capacitor coupled speaker. Having a scan of the original, I can now reproduce the exact circuit details. It was a very simple amp, and used quasi-complementary symmetry for the output stage. For those younger than I who have no idea what I'm talking about, quasi-complementary symmetry was a scheme used in the days when PNP power transistors were expensive and silicon devices were pretty much useless. If you wanted any sort of voltage and current rating, you had to use NPN devices. The quasi-complementary output stage used a (discrete) Darlington for the positive side, and a complementary pair for the negative (i.e. a PNP driver coupled to an NPN power transistor).

Meanwhile, in those days, if you wanted high gain and reasonable current capacity, germanium transistors still ruled supreme. Provided they were used in applications where leakage was not a major problem, germanium devices worked very well - this did not really include the output stages of power amps though. Also, back then the majority of loudspeakers were 16 Ohms, with only a few venturing down to 8 Ohms. Anything lower than that was almost unheard of in 1964.

Figure 1 shows the circuit - it was a cheap amp compared to most offerings of the day. It also managed to sound respectable - again by comparison - and I and many of my friends of the day built these amps with abandon - guitar amps, hi-fi, you name it, El-Cheapo was in there!

Note that the transistor types are the original specified devices. Most are obsolete now, but a list is shown below of suitable candidates.

Figure 1 - Original El-Cheapo Circuit

These were the days when the 2N3055 was the pre-eminent power transistor (NPN of course), and there were no vaguely equivalent PNP devices for less than about 5 times the price, and even these were highly inferior. As a result, the quasi-complementary output was very common, and indeed this is still the case with most IC power amps. The quasi-complementary output stage was the most popular until relatively recently, until decent PNP power devices became more readily available. Immediately, just about everyone started using NPN and PNP Darlington coupled devices for the output stages (as shown for Q3 and Q4) - the funny part is that it was demonstrated back in the mid 1970's that the full Darlington connection actually sounds (or at least measures) worse than quasi-complementary stages. Is not progress a wonderful thing?

The input stage of the El-Cheapo is not subject to the phase problems of the long tailed pair, since the Class-A driver (or VAS - Voltage Amplification Stage) is used as the input. Amps driven in this manner tend to be inherently stable. There is a major problem with DC offset of course - the input is referenced to the negative supply. If this is earth (ground) then it's not an issue, but it precludes using this design with a dual supply. The DC was not a problem with capacitor coupled speakers.

As shown, the gain for audio frequencies is 18 (25dB), which means an input sensitivity of 1V for an output of 40W. The closed loop gain is set by R4 and R7. Since the feedback is taken after the output coupling cap, the latter has no influence on the low frequency response - however, this arrangement creates an underdamped filter network that causes a 4.5dB peak at about 5Hz. Increasing C7 to 4700uF eliminates this problem for all intents and purposes.

In the original article, there were several variations of the design, however I will only present the amp in basic 40W form here. The variants were mainly based on using lower supply voltages, but included a dual (parallel) output stage for the odd low impedance load.

Note that the amp is inverting, and the input impedance of the power amp itself is 1k (R4). Because of this, there is an emitter follower (Q1) before the amp proper to convert the impedance to something usable. The arrangement shown is less than ideal though - a better solution would be to delete everything to the left of C2, and drive the circuit from an opamp (C2 would have to be reversed if the opamp uses dual supplies).

Q1	BC559
Q2	BD139
Q3	BD139
Q4	BD140
Q5	2N3055
Q6	2N3055

Suggested Modern Transistors

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Regulated Power Supply
The power supply was specified as regulated, and for a single supply amp with low open-loop gain this is a good idea to maintain low hum levels. Using a regulated supply is not normally desirable, but in this case was probably warranted. Germanium transistors were used as shown in Figure 2 (all medium and high power germanium transistors are/were PNP). Since the amp will have a PSRR (Power Supply Rejection Ratio) of only about 36dB, supply noise will be a problem with an unregulated supply. It is worth noting that the emitter follower stage (Q1) contributes most of the supply noise - another good case for driving the amp from an opamp stage.

The regulator is only simple, but would have worked well enough as shown. The Zener diode would normally be a 62V 1W unit, to obtain a 60V supply voltage for the amp (equivalent to using ±30V with a more conventional split supply). By the standards of today, the filter caps are probably too small (as is the speaker coupling cap), but I am presenting this as it was originally described.

Figure 2 - The Original Power Supply (Using Germanium Transistors)

I have spared readers the potential agony of the pilot lamp and its ballast resistor (LEDs? In 1964? The LED was only invented in 1962, and was still a curiosity when this design was published). If anyone really wants to build an original El-Cheapo then I'm sure you can work the details out for yourself. In case you may consider asking ... No, I will not assist. Same applies for the germanium transistors originally used - they are obsolete, and there is simply no point specifying the type numbers.

All diodes should be rated at 5A minimum, and 400V types should be used.

Figure 2 - Power Supply Modified to Use Silicon Transistors

The regulator shown in Figure 3 is a better proposition these days, and silicon NPN transistors can be used for Q1 and Q2. A single Darlington device could also be used. It may be necessary to reduce R1 from the 820 Ohms shown, depending on the gain of the transistors. Again, I will leave that to prospective constructors (assuming that anyone wants to build one ).

Despite initial appearances, the two regulator circuits are functionally identical. Since the circuit of Figure 3 is likely to be the most commonly used (if it is ever used), and suitable transistors would be BD139 for Q1, and 2N3055 for Q2. The transformer secondary should be 55V RMS, and this will give an unregulated voltage of around 77V. That means that only 17V will be dropped across the regulator, and with a worst case current of well under 4A (both channels, and assuming 8 Ohm speakers!) the peak dissipation will be around 38W - the average will be a lot less. Transformer rating is around 250VA - a lot higher than you'd expect because of the regulator.

Needless to say, the regulator requires a heatsink as well as the amplifier output transistors, so you will spend a lot more on heatsinks than components.

The mains fuse will need to be a slow-blow type, and the amp supply fuses must be fast blow.

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Conclusion
There's not a great deal to say about the amp. It is simple, and as such may appeal to some readers. The three diode string sets the bias, and it will be found to be quite variable in real life. Ideally, the diodes should be mounted in contact with the heatsink, but if the sink is adequately sized this should not be necessary.

The input capacitor is much larger than it needs to be, and there is a real benefit if it is reduced to 1uF. Since input impedance is about 50k at the base of the emitter follower (Q1), a 1uF input cap will still provide a -3dB frequency of just under 4Hz - provided the output cap is increased to 4700uF.

With an open loop gain of only 180 (45dB), there is not as much feedback as we are used to with modern amps. However, the amp remains essentially flat to 10kHz open loop, and this is dramatically better than most amps having a massively high open-loop gain. Because of the small amount of feedback, it may be thought that output impedance would be somewhat higher than we have come to expect. This is not the case though, and Z_outwill normally be less than 100 milliohms (a damping factor of >80 for an 8Ω load).

Speaking of feedback - because the input stage creates an inherently stable amp, there is no reason to expect that TIM (Transient Intermodulation Distortion - assuming that you believe it exists of course *) will be a problem, since feedback is simply applied to the base of the input amp, and very little frequency "compensation" is needed. Although a 68pF cap was specified for the original, it should be possible to reduce this if wider open loop bandwidth is your goal.

* TIM was once claimed to be the cause of alleged 'bad sound' from transistor amplifiers, but its very existence has been challenged, with virtually no-one being able to produce it in any sensible amplifier design. With a realistic signal input (such as music), I have never seen any of the problems associated with TIM - the only way it can be induced is to feed an amplifier with a signal that is not representative of any normal music signal.

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Construction Hints

Construction is non-critical, within the normal bounds of amplifier building at least, and will not be discussed in any detail. I will, however, make the following observations ...

• I would recommend that the speaker coupling cap be as large as practicable. Measurements made by Doug Self (and others) show low frequency distortion is generated by electros (although the actual mechanism that creates the distortion is unclear). What is clear is that the distortion becomes measurable when the reactance of the cap becomes significant with respect to the load impedance.
• The trimpot VR1 is used to set the DC voltage at the output to ½ the supply voltage (± 1V). This should be set finally after the amp has had time to stabilise, which will require at least 30 minutes of operation.
• Make sure that there is sufficient heatsinking for the power transistors to avoid excessive temperature rise. I tend to prefer a heatsink which is too large rather than the other way 'round, and anything better than about 1°C / Watt should be good - if a little on the large and expensive side. This will be the same for any amplifier you build, regardless of complexity for a given output power.
• With this amp, quiescent power will vary depending on the forward voltage drop of D1-D3. It is uncommon - but possible - for amps to run at their worst case dissipation during normal use, but it should be accounted for. With a heatsink of 1°C/W, this means that the transistors may reach a temperature of 100°C or more, which will reduce their life expectancy considerably. With heatsinks, size does matter.
• Because of the limitation described above, there is a great deal to commend using a traditional transistor bias servo to replace D1-3 in the power amp. An example is shown in the P3A amplifier (Project 3A - Q9, VR1 and R16). In the circuit presented here, the transistor should be in good thermal contact with the heatsink.

engineering projects Minor projects list, 1. Digital Thermometer 2. Infrared Remote controlled for home appliances switch 3. Digital Combination Lock

engineering projects Minor projects list,

1. Digital Thermometer
2. Infrared Remote controlled for home appliances switch
3. Digital Combination Lock
4. Security System Using laser Rays
5. Digital Clock
6. FM Transmitter
7. Advanced FM Transmitter
8. FM Receiver
9. Multi Siron (Police siron, ambulance siron,Fire Brigade siron, Machine gun )
10. Automatic Water level controller
11. Automatic Water level controller with spoken Message (pani ki tankibhar gayi hai, kripaya motor band karen, attention please your water tank is full please shut off the motor)
12. Automatic advanced water level controller
13. Fire alarm
14. Automatic traffic light controller
15. 25 Tune ( Hindi song tunes )Musical bell
16. Gayatri Mantra Continious mantra chanting machine
17. Maha-mrityunjay mantra Continuous mantra chanting machine
18. Namokar mantra Continious mantra chanting machine
19. Shiram jairam jai jai ram Continuous mantra chanting machine
20. Sun-Down switch( Advanced Street light controller)
21. Visitor counter
22. Pollution controlling Tower ( It filters the solid particles from smoke)
23. Effect of current through a magnetic coil
24. Generation of electricity by moving magnetic field
25. Clap switch
26. Two digit industrial object counter
27. Three digit industrial object counter
28. Advanced Ni-Cad Battery Charger
29. Mobile charger using IC 555
30. Earth quack sensor
31. Business shops shutter guard
32. Robotic Car (Controlled By Wired Remote Control)
33. Robotic Car (Controlled by Radio Frequency Remote control)
34. Model Of Voting Machine
35. Copper Electro Plating
36. Wind Mill (Electricity generation by wind)
37. Mobile shield
38. Intelligent automatic Three phase shifter system
39. Fastest Finger Quiz Master
40. Disco Light (Running Lights)
41. Magic tester (Can Detect electricity from distance and is very useful in finding faults)
42. Fused Tube Glower (this circuit is used to glow even Fused tub light)
43. Laser light fence ( A Security system to cover your whole house)
44. Parrot sound Electric Doorbell
45. Over Voltage Electricity Tripping switch
46. Power saving Electronic Choke For Tube-Lights
47. Solid State Lamp (Bulb) dimmer
48. Water level indicator (Shows the level of water in overhead water tank)
49. Variable Regulated Power Supply (0-32Volts)
50. Automatic Night Lamp
51. Extra ordinary staircase light switch
52. Automatic railway gate controller
53. Ultrasonic mosquito repellent
54. Letter box indicator
55. Multi purpose mix amplifier
56. Visual telephone locator (Electric bulb will glow on ringing the telephone bell)
57. Quiz Timer
58. Intercom
59. Dancing bulb on music (the intensity of light changes with the sound)
60. Listening bug
61. Infra red shadow detector
62. Temperature controller
63. Zener diode tester
64. Head phone amplifier
65. Magic Organ (light operated music generation)
66. Telephone tapping detector (If anyone lifts the phone in parallel connected phone)
67. Toy Telephone
68. Rain alarm
69. Electronic magic door lock using password
70. Lie detector
71. Mosquito repellent machine
72. Telephone Call detector
73. Fuse tube light glower without any choke
74. Morning alarm
75. Magic telephone lock
76. 3 in 1 circuit (light blinker, rain alarm, water tank alarm, light detector)
77. Low price hearing aid
78. Rat repellent machine
79. Automatic Phase Changer
80. Flying Saucer
81. Anti-Collision Rear Light
82. Light Fence
83. MAT Switch
84. 5-Bands Graphic Equalizer
85. Clock Timer
86. Fully Automatic Emergency Light
87. IR Music Transmitter and Receiver
88. Electronic Horn
89. Ultrasonic Proximity Detector
90. Secret Bell
91. Variable Power Supply Using a Fixed-Voltage Regulator IC
92. Appliance Timer-Cum-Clap Switch
93. Telephone-Operated Calling System
94. Front Door Guard
95. Bell-Cum Light Controller
96. Friendly Charger for Mobile Phones
97. Hearing Aid
98. Speed Control of DC Motor Using Pulse-Width Modulation
99. Remote-Controlled Fan Regulator
100. Low-Power Voltage Doublers
101. Parrot-Sounding AC Doorbell
102. Multi-Melody Generator with Instrumental Effect
103. School/College Quiz Buzzer
104. Visual AC Mains Voltage Indicator
105. Simple Short-Wave Transmitter
106. Solar Lighting System
107. Infrared Bug
108. Picnic Lamp
109. Versatile Power Supply
110. Ultrasonic Proximity Detector
111. Shadow Alarm
112. IR Burglar Deterrents
113. Versatile Water-Level Controller
114. Automatic-Off Timer for CD Players
115. Heat-Sensitive Switch
116. Sensitive Vibration Detector
117. Digital Dice
118. Remote-Controlled Power-Off Switch
119. Little Door Guard
120. Stress Meter
121. Teleconferencing System
122. Medium-Power FM Transmitter
123. Smart Cell phone Holder
124. Fuel Reserve Indicator for Vehicles
125. Brake Failure Indicator

Automatic Railway Gate Control & Track Switching( LATEST) Present project is designed using 8051 microcontroller to avoid railway accidents happening

Present project is designed using 8051 microcontroller to avoid railway accidents happening at unattended railway gates, if implemented in spirit. This project utilizes two powerful IR transmitters and two receivers; one pair of transmitter and receiver is fixed at up side (from where the train comes) at a level higher than a human being in exact alignment and similarly the other pair is fixed at down side of the train direction. Sensor activation time is so adjusted by calculating the time taken at a certain speed to cross at least one compartment of standard minimum size of the Indian railway. We have considered 5 seconds for this project. Sensors are fixed at 1km on both sides of the gate. We call the sensor along the train direction as ‘foreside sensor’ and the other as ‘aft side sensor’. When foreside receiver gets activated, the gate motor is turned on in one direction and the gate is closed and stays closed until the train crosses the gate and reaches aft side sensors. When aft side receiver gets activated motor turns in opposite direction and gate opens and motor stops. Buzzer will immediately sound at the fore side receiver activation and gate will close after 5 seconds, so giving time to drivers to clear gate area in order to avoid trapping between the gates and stop sound after the train has crossed.

The same principle is applied for track switching. Considering a situation wherein an express train and a local train are traveling in opposite directions on the same track; the express train is allowed to travel on the same track and the local train has to switch on to the other track. Two sensors are placed at the either sides of the junction where the track switches. If there’s a train approaching from the other side, then another sensor placed along that direction gets activated and will send an interrupt to the controller. The interrupt service routine switches the track. Indicator lights have been provided to avoid collisions. Here the switching operation is performed using a stepper motor. Assuming that within a certain delay, the train has passed the track is switched back to its original position, allowing the first train to pass without any interruption. This concept of track switching can be applied at 1km distance from the stations.The project is simple to implement and subject to further improvement.

Model of Automatic Railway Gate Control & Track Switching

Gate Control:

Railways being the cheapest mode of transportation are preferred over all the other means .When we go through the daily newspapers we come across many railway accidents occurring at unmanned railway crossings. This is mainly due to the carelessness in manual operations or lack of workers. We, in this project has come up with a solution for the same. Using simple electronic components we have tried to automate the control of railway gates. As a train approaches the railway crossing from either side, the sensors placed at a certain distance from the gate detects the approaching train and accordingly controls the operation of the gate. Also an indicator light has been provided to alert the motorists about the approaching train.

Gate control

Hardware Description

The project consists of four main parts:
8051 microcontroller
IR Transmitter
IR Receiver
Stepper Motor Circuit

8051 Microcontroller

The I/O ports of the 8051 are expanded by connecting it to an 8255 chip. The 8255 is programmed as a simple I/O port for connection with devices such as LEDs, stepper motors and sensors. More details of the 8255 are given later.
The following block diagram shows the various devices connected to the different ports of an 8255. The ports are each 8-bit and are named A, B and C. The individual ports of the 8255 can be programmed to be input or output, and can be changed dynamically. The control register is programmed in simple I/O mode with port A, port B and port C (upper) as output ports and port C (lower) as an input port.

Block diagram of 8051 Microcontroller

IR Circuits

This circuit has two stages: a transmitter unit and a receiver unit. The transmitter unit consists of an infrared LED and its associated circuitry.

IR Transitter

The transmitter circuit consists of the following components:
IC 555
Resistors
Capacitors
IR LED

The IR LED emitting infrared light is put on in the transmitting unit. To generate IR signal, 555 IC based astable multivibrator is used. Infrared LED is driven through transistor BC 548.

IC 555 is used to construct an astable multivibrator which has two quasi-stable states. It generates a square wave of frequency 38kHz and amplitude 5Volts. It is required to switch ‘ON’ the IR LED.

IR Transmitter

IR Receiver

The receiver circuit consists of the following components:
TSOP1738 (sensor)
IC 555
Resistors
Capacitors

The receiver unit consists of a sensor and its associated circuitry. In receiver section, the first part is a sensor, which detects IR pulses transmitted by IR-LED. Whenever a train crosses the sensor, the output of IR sensor momentarily transits through a low state. As a result the monostable is triggered and a short pulse is applied to the port pin of the 8051 microcontroller. On receiving a pulse from the sensor circuit, the controller activates the circuitry required for closing and opening of the gates and for track switching. The IR receiver circuit is shown in the figure below.

IR Receiver

Stepper motor circuit

Stepper motor circuit

Here a stepper motor is used for controlling the gates. A stepper motor is a widely used device that translates electrical pulses into mechanical movement. They function as their name suggests – they “step” a little bit at a time. Steppers don’t simply respond to a clock signal. They have several windings which need to be energized in the correct sequence before the motor’s shaft will rotate. Reversing the order of the sequence will cause the motor to rotate the other way.

Track Switching

Using the same principle as that for gate control, we have developed a concept of automatic track switching. Considering a situation wherein an express train and a local train are travelling in opposite directions on the same track; the express train is allowed to travel on the same track and the local train has to switch on to the other track. Indicator lights have been provided to avoid collisions .Here the switching operation is performed using a stepper motor. In practical purposes this can be achieved using electromagnets.

Track Switching

LIST OF MICROCONTROLLER BASED PROJECTS AT-89C51 BASED MICROCONTROLLER AT-89C51 BASED METRO TRAIN PROTOTYPE USING LCD: The project shows resemblance as

LIST OF MICROCONTROLLER BASED PROJECTS AT-89C51 BASED

MICROCONTROLLER AT-89C51 BASED METRO TRAIN
PROTOTYPE USING LCD: The project shows resemblance as
you are traveling in metro train. It will display three station at LCD
and a stepper motor to rotate clock or anti-clock wise.(with or
without vehicle)
ASM
MICROCONTROLLER AT-89C51 BASED VOTING
MACHINE: The voting system for four candidates with memory
backup to restore the results to be viewed with password.
ASM
MICROCONTROLLER AT-89C51 BASED TEXT EDITOR
CUM MOVING MESSAGE DISPLAY: The project comprises 30
keys to edit any message in English.One can restore the message in
memory IC. The 16 characters at a time can be view in running
mode.
C &
ASM
MICROCONTROLLER AT-89C51 BASED FULL FUNCTION
STEPPER MOTOR CONTROLLER :The project will operate
the stepper motor in almost all modes viz. clock, anticlock, speed
and frequency control with time duration for both directions.
ASM
MICROCONTROLLER AT-89C51 BASED WATER LEVEL
CONTROLLER CUM MOTOR PROTECTOR: It can indicates
the level and control the water pump at top level filling.
ASM
MICROCONTROLLER AT-89C51 BASED SIMPLE
STEPPER MOTOR CONTROLLER: A simple stepper motor
controller circuit with direction change only.
ASM
MICROCONTROLLER AT-89C51 BASED CALL
MONITORING SYSTEM: An economical room monitoring
system for eight channels and with buzzer indication and seven
segment display provides feed back to the caller.
ASM
MICROCONTROLLER AT-89C51 BASED INDUSTRIAL
FAULT MONITORING SYSTEM: It will check the faults like
ASM
over temperature, humidity, power failure, over voltage etc. at the
monitor. One can link this with RF data encoders/decoder for
wireless link.
MICROCONTROLLER AT-89C51 BASED SAFETY GUARD
FOR BLIND: This embedded safety guard system with voice
processor to play the prerecorded message in case of any obstacle is
detected by the blind person.
C
MICROCONTROLLER AT-89C51 BASED FASTEST
FINGER FIRST: Useful for Quiz games, dumb charades. It
display the player no. along with the beep for seven players.
ASM
MICROCONTROLLER AT-89C51 BASED TEMPERATURE
METER: It will display the room temperature on LCD and one can
set the desired value to indicate the alarm or control at a desired
teperature. It uses an ADC to interface with LM-35 sensor.
ASM
MICROCONTROLLER AT-89C51 BASED INFRARED
REMOTE CONTROLLED SWITCH BOARD: (4
APPLIANCES):One can operate (on/off) four electrical devices
with TV remote syncronised with circuit independently.
ASM
MICROCONTROLLER AT-89C51 BASED RANK DISPLAY
SYSTEM FOR RACE & QUIZ COMPETITION WITH LCD:
It can resolve the time difference(may be few milliseconds) and
indicate the correct ranking between the individuals denoted A to H
ASM
MICROCONTROLLER AT-89C51 BASED AUTO GEAR
SHIFTING SYSTEM: The circuit shows the demo of auto shifting
of gears using stepper motor with the change in speed of vehicle.
One can change the speed of DC motor as actual vehicle running
wheel.
C
MICROCONTROLLER AT-89C51 BASED AUTO SPEED
LIMITER/GOVERNER WITH AUTO BREAKING: The
project is to read the rpm of a automobile and according to that it
limits the speed as Speed Governor. One can change the speed with
variable control.
C
MICROCONTROLLER AT-89C51 BASED LINE
FOLLOWER ROBOT: A Robotic car that follows the black line
at the floor area based on IR sensors with transmitters and receivers.
ASM
MICROCONTROLLER AT-89C51 BASED ‘YES MASTER’
FOLLOWER : A robotic car that follows his master who is
sending an IR transmission always.
ASM
MICROCONTROLLER AT-89C51 BASED OVER CURRENT
RELAY: The circuit senses the over current and limit the relay .
MICROCONTROLLER AT-89C51 BASED VOLTAGE/
POWER FACTOR / FREQUENCY METER: The project check
the electrical input factors as multifunction meter.
MICROCONTROLLER AT-89C51 BASED DATA DRIVEN
DISPLAY : It shows how you can use the controller to drive an
LCD module and in turn use it as a handheld device to set the
parameters of the control unit through RS-232 serial link. It
comprises two units – Control unit and a LCD module unit. Any
wired or wireless link like IR can be used to display the unit.
MICROCONTROLLER AT-89C51 BASED TELEREMOTE
SWITCH: The project can is to remotely control four electrical
devices using a landline or mobile to be connected with the circuit.
MICROCONTROLLER AT-89C51 BASED TRIPPING SEQUENCE
CODE INDICATOR: The electrical utility project that indicates the MCB
tripped on the first if short circuit arises and the sequence for total eight
areas.
ASM
MICROCONTROLLER AT-89C51 BASED RFID ATTENDENCE
MONITOR: The project will show the names of person who had pressed
the RFID key on LCD. One can use DATA encoder/decoder circuit.
MICROCONTROLLER AT-89C51 BASED LED LIGHT CHASER: With
the help of this one can display 5 different effects for running lights for 24
lights. One can change the speed also.
‘c’

Mini Audio Spectrum Analyzer LM3915 The circuit has been designed to create a spectrum analyzer that will provide an analysis of a sound to determine

Mini Audio Spectrum Analyzer LM3915

The circuit has been designed to create a spectrum analyzer that will provide an analysis of a sound to determine at various frequencies, the volume of sounds that make up the overall sound spectrum.

Circuit Explanation
The device is sensitive enough to determine the sound wave components of frequency and amplitude with the changing of frequency and the width of an acoustic signal. The proportionality of signal width is indicated by the brightness of LED as it turns ON while the color indicates the proportionality offrequency. In order for the red LED to turn ON in strong signal, the sensitivity of the input circuit is adjusted by resistor R2. The middle signal is represented by a yellow LED while the low signal is indicated the green LED.

The 10 LEDs in 3 lines comprise the display unit which is ensured the IC2 as it functions as a counter decoder represented by the two gates ICa-b.thefrequency of the counter is being regulated by R6. No LED will turn ON in the absence of any signal in the input. The LEDs will begin to flicker or blink depending on the intensity and tempo of the signal, once a signal has been applied in the input. The values of the resistors R4 & R5 can be varied that will be suitable for the desired requirements. Alternatively, this can be done by placing a 1K ohm trimmer in place of R4 & R5 during the initial regulation and adjustment of the values. It can be eventually removed and replaced with permanent resistors as soon as the desired values are achieved. Additional LEDs can be added in connection to IC2 although thiscircuit does not precisely measure the input signal.

Part List
R1= 1K8Kohm
R2= 100Kohm trimmer
R3= 1Kohm
R4= 100 ohm…..1Kohm
R5= 100 ohm…..1Kohm
R6= 100Kohm trimmer
C1= 100nF 100V
D1….10= RED LED
D11….20= YELLOW LED
D21….30= GREEN LED
IC1= LM3915
IC2= 4017
IC3= 4011

Application
This audio spectrum analyzer is a user interface component capable of making visible the sound pressure for a range of frequencies over time by taking a sample from an audio data stream and an animated visualization during the play is created in real time. It is ideal for any purpose which includes analysis and identification of human speech, ham radio audio reception tuning, analysis of vocal and instrumental music, evaluation and tuning of musical instruments, analysis of bat echolocation sounds, evaluation and calibration of home audio systems, and analysis and identification of biological sounds. Other uses of the audio spectrum analyzer are in distortion analysis, transfer functions, and digital filtering.

Source: Mini Spectrum Analyzer for Audio/Sound by LM3915

Mini Audio Spectrum Analyzer LM3915 The circuit has been designed to create a spectrum analyzer that will provide an analysis of a sound to determine

Mini Audio Spectrum Analyzer LM3915

The circuit has been designed to create a spectrum analyzer that will provide an analysis of a sound to determine at various frequencies, the volume of sounds that make up the overall sound spectrum.

Circuit Explanation
The device is sensitive enough to determine the sound wave components of frequency and amplitude with the changing of frequency and the width of an acoustic signal. The proportionality of signal width is indicated by the brightness of LED as it turns ON while the color indicates the proportionality offrequency. In order for the red LED to turn ON in strong signal, the sensitivity of the input circuit is adjusted by resistor R2. The middle signal is represented by a yellow LED while the low signal is indicated the green LED.

The 10 LEDs in 3 lines comprise the display unit which is ensured the IC2 as it functions as a counter decoder represented by the two gates ICa-b.thefrequency of the counter is being regulated by R6. No LED will turn ON in the absence of any signal in the input. The LEDs will begin to flicker or blink depending on the intensity and tempo of the signal, once a signal has been applied in the input. The values of the resistors R4 & R5 can be varied that will be suitable for the desired requirements. Alternatively, this can be done by placing a 1K ohm trimmer in place of R4 & R5 during the initial regulation and adjustment of the values. It can be eventually removed and replaced with permanent resistors as soon as the desired values are achieved. Additional LEDs can be added in connection to IC2 although thiscircuit does not precisely measure the input signal.

Part List
R1= 1K8Kohm
R2= 100Kohm trimmer
R3= 1Kohm
R4= 100 ohm…..1Kohm
R5= 100 ohm…..1Kohm
R6= 100Kohm trimmer
C1= 100nF 100V
D1….10= RED LED
D11….20= YELLOW LED
D21….30= GREEN LED
IC1= LM3915
IC2= 4017
IC3= 4011

Application
This audio spectrum analyzer is a user interface component capable of making visible the sound pressure for a range of frequencies over time by taking a sample from an audio data stream and an animated visualization during the play is created in real time. It is ideal for any purpose which includes analysis and identification of human speech, ham radio audio reception tuning, analysis of vocal and instrumental music, evaluation and tuning of musical instruments, analysis of bat echolocation sounds, evaluation and calibration of home audio systems, and analysis and identification of biological sounds. Other uses of the audio spectrum analyzer are in distortion analysis, transfer functions, and digital filtering.

Source: Mini Spectrum Analyzer for Audio/Sound by LM3915

ICL7107 Digital LED Voltmeter [Universal Digital Voltmeter]

ICL7107 Digital LED Voltmeter

This circuit is a digital voltmeter with LED display. It's ideal to use for measuring the output voltage of your DC power supply. It includes a 3.5-digit LED display with a negative voltage indicator. It measures DC voltages from 0 to 199.9V with a resolution of 0.1V. The voltmeter is based on single ICL7107 chip and may be fitted on a small 3cm x 7cm printed circuit board. The circuit should be supplied with a 5V voltage supply and consumes only around 25mA.

The use of 7805 5V voltage regulator is highly recommended to prevent the damage of ICL7107, 555 ICs and to extend the operating voltages.

Parts list of The Digital LED Voltmeter:

R1 = 8K2 R1 = 8K2
R2 = 47K / 470K R2 = 47k / 470K
R3 = 100K R3 = 100K
R4 = 2K R4 = 2K
R5, R6 = 47K R5, R6 = 47k
R7 = 0R / 4K7 R7 = 0R / 4K7
R8 = 560R R8 = 560R
C1,C5, C6, C8, C9 = 100n C1, C5, C6, C8, C9 = 100n
C2 = 470n / 47n C2 = 470n / 47n
C3 = 220n C3 = 220n
C4 = 100p C4 = 100p
C7 = 10-22u C7 = 10-22U
D1, D2 = 1N4148 D1, D2 = 1N4148
IC1 = ICL7107 IC1 = ICL7107
IC2 = NE555 IC2 = NE555
OPTO = CA 10 pin FTA = CA 10 pin

The digital LED voltmeter can also be configured to measure different voltage ranges and display higher voltage resolution.

How to Build a Dipole FM antenna The antenna rod is made of 6 mm copper tube I found in a shop for cars. It is actually tubes for the breaks, but the

How to Build a Dipole FM antenna

The antenna rod is made of 6 mm copper tube I found in a shop for cars. It is actually tubes for the breaks, but the tube works great as antenna rods. You can use all kinds of tubes or wire. The benefit of using a tube, is that it is strong and the wider tube diameter you use, the wider frequency range (bandwidth) you will also get. I have noticed that the transmitter gives highest output power around 104-108 MHz so I set my transmitter to 106 MHz.

The calculation gave the rod length of 67 cm. So I cut off two rods at 67cm each. I also found plastic tube to hold the rods and to give it a more stable construction. I use one plastic tube as boom and a second to contain the two rods. You can see how I used black duct tape to hold the two tubes together. Inside the vertical tube are the two rods and I have connected a coax to the two rods. The coax is twisted 10 turns around the horizontal tube to form a balun (rf choke) to prevent reflections. This is a poor mans balun and lot of improvement can be done here.

Copper Material

I placed the antenna on my balcony and connected it to the transmitter and turned on power supply. I live in a medium city so I took my car and drove away to test the performance. The signal was perfect with crystal clear stereo audio. There are many concrete building around my transmitter which affects the transmitting range. The transmitter worked up to 5 km distance when the sight was clear (could not obtain line-in-sight). In city environment it reached 1-2km, due to heavy concrete.

Dipole FM Antenna Construction

I find this performance very good for a 1 W amplifier with an antenna which took me 45 min to build. One should also take in account that the FM signal is Wide FM, which consume much more energy than a narrow FM signal does. All together, I was very pleased with the result.

Antenna Testing and Measuring
Thanks to a complex antenna analyser, I have been able to get a plot of the antenna performance.
The red curve show the SWR and the grey show Z (impedance). What we want is a SWR of 1 and Z to be close match to 50 ohm.

As you can see, the best match for this antenna is at 102 MHz where we have SWR = 1.13 and Z = 53 ohm. I did run my antenna at 106 MHz, where the match is worse SWR = 1.56 and Z = 32 ohm.

Conclusion: My antenna was not perfect for 106 MHz, I should re-run my filed test at 102 MHz. I will probably get better results and longer transmitting distance. Or I should make the antenna a bit shorter to match the frequency 106 MHz.

See more: Wireless FM Transmitter

Source: How to build a dipole antenna in 45 minutes

Seiko secret agents high-quality amp Seiko secret agents high-quality amp Seiko secret agents high-quality amp tone control Seiko secret agents high-

Seiko secret agents high-quality amp

I use a switching power supply and production of high quality amp board a power amplifier was a friend of Baozou a hard lazy. Although the Dodgers in the side, but the general suspected of power too small, it is difficult to meet the dynamic needs of Baopeng programmes, in particular the relationship between several good friends to sing karaoke OK, not turning the big voice, frequently so that the output was only 10 Dodgers a few watts of serious overload distortion. So recently pick up the pieces produced a fine performance of the power amplifier.

First, the choice of amplifier circuits produced in the original amp (switching power supply, high-quality amplifier boards, circuit see Figure 1) on the basis of the set into the pitch, volume, balance and 3 D function in a high-quality audio circuit LM4610N ( Circuit see Figure 2) and substantially improve the clarity BBE music circuit XR1075, discard signal switch circuit. LM4610N electrical parameters are as follows: voltage to 9 V ~ 18V (typically for 12 V); distortion of 0.03 percent; SNR 80 dB; frequency response of 250 kHz; volume control 75 dB; balance adjustment 1 ~ 20 dB; pitch adjustment ± 15dB, The largest gain of 2 dB, while a 3 D sound field processing functions. XR1071 to chip at the core of the music circuit definition upgrade for the United States EXAR the company's second generation product, the performance is better than the first generation M2150 and Japan Roma's BA3884, its parameters: voltage ± 5V, enhance clarity of 0 ~ 9.7dB, bass upgrading of 0 ~ 9.9 dB, the circuit board components of the factory finished slightly out of choice.

Second, the specific production: the use of a power amplifier chassis scrapped the "ambitious" 250 W transistor amplifiers chassis, for all devices and removed all the panels, and the other by 3 mm thick aluminum plate in accordance with the mechanism of re-design panel request Processing. The chassis and slightly larger than the standard chassis, the size of 550 mm × 410mm × 145mm, just under the amplifier to accommodate all the circuits and components. Because of the modules are finished plate, it was only in accordance with circuit assembly when asked to make a simple connection, but must pay attention to the current channel should choose high-quality wire, and as far as possible be rough and short and to distinguish between different colors , And small current signal path also should try to select good quality and high capacity wires and signal lines. Signal from the input signal between the start of each board are connected by shielding and shielding net-line termination, to avoid induced noise. Machines that the unit should follow the grounding principle that the board first with stout ground wire (usually black) leads to one point after pooling in the case, the specific location of ground would be after repeated tests, which if done Well be the complete elimination of exchange of sound. As a reminder, most have finished circuit boards have a fixed holes, but there are 12 holes and is connected to power, such as not dealing with insulation, be fixed with screws in metal enclosure, often Formation of the multi-circuit grounding, is prone to lead the exchange sound, which is many enthusiasts in the production of audio and helpless when the source of noise. The correct approach is to use sharp blade ringing fixed holes, with the power ground wire separation, in order to achieve the purpose of that grounding. Because of the power amplifier circuit, as many as 67 units (transformers, switches, power supply), should be fully well the elements of metal and insulation between the floor and preventing earthquakes work. The author's approach is to use a 15 mm thick wooden boards (depending on the size of floor) tiles on the floor, then screw the plate with wooden floor and closely connected together, and then each circuit element Were fixed in the board. At a fixed switching power supply and power transformer before in his next to put the appropriate size of a car inner tubes, to eradicate due to shock arising from the adverse effects. Amp produced a success or not, with a level of quality of power supply has a close relationship. The audio amplifier for the two panels to provide power from one pair of exchanges of high-quality 16 V/35W E-type transformers bear, the 10 A/100V AC rectifier bridge rectifier, 2200 μ F/50V through the filter capacitance from 7812,7912 3 Regulators and NE5532-block composed of servo power regulator after two sound boards to use (see Figure 3 circuit), so high-quality power supply can LM4610N and the performance of XR1071 play to the limit. This amplifier production, give up the production amp commonly used when the connector-even, and the plate connections (including the power input, the amplifier output) are direct welding, such connection is bad and the connector could have been avoided because of the surface Oxidation caused by signal degradation and noise.

assembly, with the multimeter DC voltage measurement amplifier block the mid-point of potential output, should generally be in the 100 mV below.

Third, the trial feelings: Listen, in order not to high-quality signal to cover up the shortcomings of the power amplifier, the first by the author of the JVC TD-W205 cassette blocks to the amp, access to a new two-frequency shelves Granville me. The first two sound boards function switch to pull "OFF" position, I found the amp to-noise ratio high, static, even if the speaker is also close to the ear can not hear any noise. Take a few genuine Yindai disk, the general feeling is that open-market, the balance of good, filled with bass, and Alto bright and clear, crisp and sweet treble is fine. Later, with a new Section 330 super VCD players will JVC TD-W205 deck replaced, take a few quite familiar with their first song, I feel high bass have different degrees of extension, and will XR1071 pull the switch to function "ON" Block, clarity and bass compensation for proper regulation, then obviously wide sound field, increase the density of music, much more clarity, and have heard some never before heard the message. Quite powerful bass, 3 D of the LM4610 will be switched on, with three-dimensional sound field and throughout the entire space, surrounded by a good sense, the trial several classic films, I feel very Guoyin.