1. SUBMITTED BY EDGEFX TEAM
PRECISE ILLUMINATION CONTROL OF LAMP
SUBMITTED BY
EDGEFX TEAM

2. ABSTRACT
Based on the principle of firing angle control of thyristors on giving connection to any ac load, here a lamp from the control the circuit.
A display unit displays the full intensity or any percentage and one can enter the desired percentage to reduce the intensity
The firing angle would be automatically adjusted to maintain the load power
This operation is carried out by using two no’s of SCRs connected in back to back or a triac in series with the ac load.

3. BLOCK DIAGRAM

4. HARD WARE EQUIPMENTS POWER SUPPLY BLOCK
MICROCONTROLLER (AT89S52/AT89C51)
LCD DISPLAY
KEYPAD
LM358 (COMPARATOR)
MOC3021
BC547
1N4007
LED
RESISTORS & CAPACITORS
SCR

6. EMBEDDED SYSTEMS Definition for :- EMBEDDED SYSTEMS
A combination of hardware and software which together
form a component of a larger machine.
An example of an embedded system is a microprocessor that
controls an automobile engine.
An embedded system is designed to run on its own without
human intervention, and may be required to respond to
events in real time.

7. EMBEDDED SYSTEMS

8. AT89S52 MICRO CONTROLLER Compatible with MCS®-51 Products
8K Bytes of In-System Programmable (ISP) Flash Memory
4.0V to 5.5V Operating Range
Crystal Frequency MHZ
Three-level Program Memory Lock
256 x 8-bit Internal RAM
32 Programmable I/O Lines
Three 16-bit Timer/Counters
Eight Interrupt Sources
Full Duplex UART Serial Channel
Watchdog Timer
AT89S52

9. PIN DIAGRAM OF AT89S52

10. LED LEDs are semiconductor devices are made out of silicon
When current passes through the LED, it emits photons as a byproduct. Normal light bulbs produce light by heating a metal filament until its white hot
LEDs present many advantages over traditional light sources including lower energy consumption, longer lifetime, improved robustness, smaller size and faster switching

11. THYRISTOR (SCR)
A silicon-controlled rectifier (or semiconductor-controlled rectifier) is a four-layer solid state device that controls current The name "silicon controlled rectifier" or SCR is General Electric's trade name for a type of thyristor
An SCR consists of four layers of alternating
P and N type semiconductor materials.
Silicon is used as the intrinsic semiconductor, to which the proper dopants are added
The doping of PNPN will depend on the application of SCR, since its characteristics are similar to those of the thyratron

12. BC547 The BC547 transistor is an NPN Epitaxial Silicon Transistor.
The BC547 transistor is a general-purpose transistor in small plastic packages.
It is used in general-purpose switching and amplification BC847/BC547 series 45 V, 100 mA NPN general-purpose transistors.
Whenever base is high, then current starts flowing through base and emitter and after that only current will pass from collector to emitter

13. MOC3021 ( OPTO COUPLER )
Opto-couplers are made up of a LED and a light sensitive device, all
wrapped up in one package
no electrical connection between the two devices
The light sensitive device may be a photodiode, phototransistor, or more
esoteric devices such as thyristors, triacs etc.

14. LM 358 ( COMPARATOR ) Internally frequency compensated for unity gain.
Large dc voltage gain: 100 Db.
Wide bandwidth (unity gain): 1 MHz (temperature compensated)
Wide power supply range:
Single supply: 3V to 32V
or dual supplies: ±1.5V to ±16V
Very low supply current drain (500 µA)-essentially independent of supply voltage.
Low input offset voltage: 2 mV
Input common-mode voltage range includes ground.
Differential input voltage range equal to the power supply voltage.

15. LM 358 PIN DIAGRAM 1 - Output 1 2 - Inverting input
3 - Non-inverting input
4 – VCC-
5 - Non-inverting input 2
6 - Inverting input 2
7 - Output 2
8 – VCC+

16. Keypad
A keypad is a set of buttons arranged in a block or "pad" which usually bear digits, symbols and usually a complete set of alphabetical letters. If it mostly contains numbers then it can also be called a numeric keypad.
In order to detect which key is pressed from the matrix, the row lines are to be made low one by one and read the columns. Assume that if Row1 is made low, then read the columns.
If any of the key in row1 is pressed then correspondingly the column 1will give low that is if second key is pressed in Row1, then column2 will give low.

17. LIQUID CRYSTAL DISPLAY (LCD)
Most common LCDs connected to the microcontrollers are 16x2 and
20x2 displays.
This means 16 characters per line by 2 lines and 20 characters per line
by 2 lines, respectively.
The standard is referred to as HD44780U, which refers to the controller
chip which receives data from an external source (and communicates
directly with the LCD.

18. LCD BACKGROUND
If an 8-bit data bus is used the LCD will require 11 data lines
(3 control lines plus the 8 lines for the data bus)
The three control lines are referred to as EN, RS, and RW
EN=Enable (used to tell the LCD that you are sending it data)
RS=Register Select (When RS is low (0), data is treated as a command)
(When RS is High(1), data being sent is text data )
R/W=Read/Write (When RW is low (0), the data written to the LCD)
(When RW is low (0), the data reading to the LCD)

19. SOFTWARE REQUIREMENTS
PROGRAMMING LANGUAGES Embedded C , ALP (Assembly Language) COMPILERS: Keil 2.0/3.0uv DUMPING SOFT WARE: Using Micro controller flash Software we are dumping our HEX Code into Micro Controller

20. KEIL COMPILER WINDOW

21. BIBILOGRAPHY
The Microcontroller and Embedded systems” by Muhammad Ali Mazidi and Janice Gillispie Mazidi , Pearson Education.
ATMEL 89S52 Data Sheets.

22. THANK ‘Q’