HIGHWAY LIGHTING SYSTEM WITH AUTO TURN OFF ON DAY TIME SUBMITTED BY EDGEFX TEAM

ABSTRACT High Intensity Discharge lamps (HID) used for urban street light are based on principle of gas discharge White Light Emitting Diode (LED) can replace the HID lamps where intensity control is possible by pulse width modulation

BLOCK DIAGRAM

HARD WARE EQUIPMENTS POWER SUPPLY BLOCK MICROCONTROLLER (AT89S52/AT89C51) LED PWM LDR(LIGHT DEPENDENT RESISTOR) MOSFET BC547 1N4007 RESISTORS & CAPACITORS

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.

EMBEDDED SYSTEMS

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 11.0592MHZ 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

PIN DIAGRAM OF AT89S52

LDR(Light Dependent Resistor) A photoresistor or light dependent resistor (LDR) is a resistor whose resistance decreases with increasing incident light intensity. It can also be referred to as photoconductor. If light falling on the device, the photons absorbed by the semiconductor give bound electrons enough energy to jump into the conduction band. The resulting free electron (and its hole partner) conduct electricity, thereby lowering resistance.

A photoelectric device can be either intrinsic or extrinsic A photoelectric device can be either intrinsic or extrinsic. An intrinsic semiconductor has its own charge carriers and is not an efficient semiconductor, e.g. silicon. Extrinsic devices have impurities, also called dopants, added whose ground state energy is closer to the conduction band; since the electrons do not have as far to jump, lower energy photons (i.e., longer wavelengths and lower frequencies) are sufficient to trigger the device. Example of extrinsic devices is phosphorous atoms

PWM The PWM switching frequency has to be much faster than what would affect the load, which is to say the device that uses the power. 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.

PWM APPLICATIONS Telecommunications Power delivery Voltage regulation Audio effects and amplification.

MOSFET Metal–Oxide–Semiconductor field-effect transistor (MOSFET, MOS-FET, or MOS FET) MOSFET is a device used for amplifying or switching electronic Signals

MOSFET as a switch & P- Type , N-Type MOSFET

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  

BIBILOGRAPHY The 8051 Microcontroller and Embedded systems” by Muhammad Ali Mazidi and Janice Gillispie Mazidi , Pearson Education. ATMEL 89S52 Data Sheets. www.atmel.com www.beyondlogic.org www.wikipedia.org www.howstuffworks.com www.alldatasheets.com

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