1. Under the Guidance of Submitted by
Project Title
LED BASED STREET LIGHT WITH PROGRAMMABLE INTENSITY CONTROL USING SOLAR POWER FROM PHOTOVOLTAIC CELLS
Under the Guidance of
Submitted by

2. ABSTRACT
High Intensity Discharge lamps (HID) used for urban street light are based on principle of gas discharge, thus the intensity is not controllable by any voltage reduction method as the discharge path is broken.
White Light Emitting Diode (LED) can replace the HID lamps where intensity control is possible by pulse width modulation. The intensity control helps in saving energy during late nights while traffic density on the streets is low.
A programmable microcontroller is engaged to provide different intensities at the different times of late night for energy saving for solar based system, using a charge controller for battery charging, overload and deep discharge protection

3. PROJECT BLOCK DIAGRAM

4. PHOTOVOLTAIC CELLS/SOLAR CELLS LM324 1N4007/1N4148 RESISTOR CAPACITOR
HARDWARE REQUIREMENTS
POWER SUPPLY BLOCK
MICROCONTROLLER (AT89S52/AT89C51)
SOLAR PANNEL
LED
PWM
MOSFET
PHOTOVOLTAIC CELLS/SOLAR CELLS
LM324
1N4007/1N4148
RESISTOR
CAPACITOR

5. POWER SUPPLY Bridge rectifier 5v Regulator 230 V AC 50 Hz 5V DC
Filter(470µf)
12V step down
transformer

6. It is a smaller computer Has on-chip RAM, ROM, I/O ports...
MICROCONTROLLER
It is a smaller computer
Has on-chip RAM, ROM, I/O ports...
RAM
ROM
I/O Port
Timer
Serial COM Port
Microcontroller
CPU
A single chip

7. INTERNAL STRUCTURE OF A MICRO CONTROLLER-AT89S52/51
CPU
On-chip RAM
On-chip ROM for program code
4 I/O Ports
Timer 0
Serial Port
OSC
Interrupt Control
External interrupts
Timer 1
Timer/Counter
Bus Control
TxD RxD
P0 P1 P2 P3
Address/Data
Counter Inputs

8. Features of AT89S51/52 Compatible with MCS®-51 Products
8K Bytes of In-System Programmable (ISP) Flash Memory
Endurance: 10,000 Write/Erase Cycles
4.0V to 5.5V Operating Range
Fully Static Operation: 0 Hz to 33 MHz
256 x 8-bit Internal RAM
32 Programmable I/O Lines
Three 16-bit Timer/Counters
Eight Interrupt Sources
Full Duplex UART Serial Channel
Interrupt Recovery from Power-down Mode
Watchdog Timer
Dual Data Pointer

9. Pin Description

10. PWM(Pulse width modulation)
The term duty cycle describes the proportion of on time to the regular interval or period of time; a low duty cycle corresponds to low power, because the power is off for most of the time.
Duty cycle is expressed in percent, 100% being fully on.
The main advantage of PWM is that power loss in the switching devices is very low. When a switch is off there is practically no current, and when it is on, there is almost no voltage drop across the switch.
PWM works also well with digital controls, which, because of their on/off nature, can easily set the needed duty cycle.
The longer the switch is on compared to the off periods, the higher the power supplied to the load is.

11. PWM(Pulse width modulation)

12. MOSFET(IRF 510)
The metal–oxide–semiconductor field-effect transistor (MOSFET, MOS-FET, or MOS FET) is a device used for amplifying or switching electronic signals
The basic principle of the device a voltage on the oxide-insulated gate electrode can induce a conducting channel between the two other contacts called source and drain
It is by far the most common transistor in both digital and analog circuits, though the bipolar junction transistor was at one time much more common.

13. OPAMP LM324 Features Internally frequency compensated for unity gain
Large DC voltage gain 100 dB
Wideband with 1Mhz (Temperature compensated)
Wide power supply range:
Single supply 3V to 32V
or dual supplies ±1.5V to ±16V
Very low supply current drain (700 μA) essentially independent of supply voltage
Low input biasing current 45 nA (temperature compensated)
Low input offset voltage 2mV and offset current:5 nA
Large output voltage swing 0V to V+ − 1.5V

14. BC547 (NPN –Transistor)
The BC547 transistor is an NPN Epitaxial Silicon Transistor.
It is used in general-purpose switching and amplification BC847/BC547 series 45 V, 100 mA NPN general-purpose transistors.
The ratio of two currents (Ic/Ib) is called the DC Current Gain of the device and is given the symbol of hfe or nowadays Beta, (β).

15. The current gain from the emitter to the collector terminal, Ic/Ie, is called Alpha, (α), and is a function of the transistor itself

16. 1N4148
The 1N4148 is a standard small signal silicon diode used in signal processing.
The 1N4148 is generally available in a DO-35 glass package and is very useful at high frequencies with a reverse recovery time of no more than 4ns.
This permits rectification and detection of radio frequency signals very effectively, as long as their amplitude is above the forward conduction threshold of silicon (around 0.7V) or the diode is biased.

17. PHOTOVOLTAIC CELLS
Photovoltaic (PV) cells are made of special materials called semiconductors such as silicon, which is currently the most commonly used.
Basically, when light strikes the cell, a certain portion of it is absorbed within the semiconductor material.
PV cells also all have one or more electric fields that act to force electrons freed by light absorption to flow in a certain direction.
This flow of electrons is a current, and by placing metal contacts on the top and bottom of the PV cell, we can draw that current off to use externally.

18. SOLAR PANEL
Expose the cell to light, and the energy from each photon (light particle) hitting the silicon, will liberate an electron and a corresponding hole.
If this happens within range of the electric field’s influence, the electrons will be sent to the N side and the holes to the P one, resulting in yet further disruption of electrical neutrality
This flow of electrons is a current; the electrical field in the cell causes a voltage and the product of these two is power

19. WORKING OF PROJECT
Solar panel being a current source is used to change battery B1 via D10. While the battery is fully charged the voltage at cathode point of D10 goes up. This results in the set point voltage at pin 3 of U1:A to go up above the reference voltage because the potential divider formed out of R12, 5K variable resistor,R13 goes up.
This results in pin no 1 of U1:A to go high to switch ‘ON’ the transistor Q1 that places drive voltage to the Mosfet IRF640 .such that the current from solar panel is bypassed via D11 and the Mosfet drain and source
Simultaneously pin 7 of U1:B also goes high to drive a led D1 indicating battery is being fully charged
Whenever the solar charge is low the circuit utilizes the power from battery, if the battery goes into deep discharge ,then it utilizes power from solar power then the Led’s flashes light

20. Software Requirements
Keil an ARM Company makes C compilers, macro assemblers, real-time kernels, debuggers, simulators, integrated environments, evaluation boards, and emulators for ARM7/ARM9/Cortex-M3, XC16x/C16x/ST10, 251, and 8051 MCU families.
Compilers are programs used to convert a High Level Language to object code. Desktop compilers produce an output object code for the underlying microprocessor, but not for other microprocessors.

21. i.e the programs written in one of the HLL like ‘C’ will compile the code to run on the system for a particular processor like x86 (underlying microprocessor in the computer).
For example compilers for Dos platform is different from the Compilers for Unix platform  So if one wants to define a compiler then compiler is a program that translates source code into object code.

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

23. THANKYOU