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Coin based mobile charger project report

Apr 15, 2017





1.1.1 COIN INSERTION MOBILE CHARGERThis is the smart coin based mobile charging system that charges your mobile for particular amount of time on inserting a coin. The system is to be used by shop owners, public places like railway stations to provide mobile charging facility. So the system consists of a coin recognition module that recognizes valid coin is found it signals the microcontroller for further action. if a valid coin is found it signals the microcontroller and microcontroller then starts the mobile charging mechanism providing a 5v supply through a power supply through a power supply section to the mobile phone, now systems also needs to monitor the amount of charging to be provided .So the system can be used for smart mobile charging at public places.

The objective of this project is inserting the coin using charge for your mobile phone in public places. This project is very useful to people who are all using mobile phone without charging condition in public places. In this project, who are all using mobile phones in outside of home are office without charging condition. The coin based mobile phone charger is very useful to that person for using coin to charge for that mobile. A sensor system is used to detect the presence of coin. It may be of different type (IR sensor, Using LDR etc...). The coin is inserted between the transmitted and received signal.When a signal came from sensor unit, the microcontroller activates the charger unit for a predefined time. After that it will reset to normal case. Driver circuit is used for provide the sufficient input voltage of relay. The relay will on to activate the 230v charger, we will use charger to charge for our mobile phone.The major action in this system is controlled by transmitter section; this section consists of IR transmitter and IR receiver. Here we need to generate IR frequency continuously. So that by using a small tiny microcontroller frequency is produced and is connected IR receiver continuously receives the signals from the transmitter. Whenever the light path in between IR transmitter and IR receiver cuts by an obstacle receiver signal gives low to high pulse. By

to the IR led to generate IR light rays of 38 KHz frequency.Connecting the receiver output to the micro controller interrupt pin, it gives interrupt to the micro controller immediately the system gives the buzzer and sends the message to the display on LCD display to the micro controller.

CHAPTER 22.1 System module

Fig:-2.1 Project Module

2.2 8051 Microcontroller The microcontroller memory is divided into Program Memory and Data Memory. Program Memory (ROM) is used for permanent saving program being executed, while Data Memory (RAM) is used for temporarily storing and keeping intermediate results and variables. Depending on the model in use (still referring to the whole 8051 microcontroller family) at most a few Kb of ROM and 128 or 256 bytes of RAM can be used. However--

All 8051 microcontrollers have 16-bit addressing bus and can address 64 kb memory. It is neither a mistake nor a big ambition of engineers who were working on basic core development. It is a matter of very clever memory organization which makes these controllers a real programmers tidbit.

2.2.1 Pin Diagram:

Fig:-2.2.1 PIN Diagram 8051 Microcontroller

2.2.2 PIN Description:

Pins 1-8: Port 1 Each of these pins can be configured as input or output.

Pin 9: RS Logical one on this pin stops microcontrollers operating and erases the contents of most registers. By applying logical zero to this pin, the program starts execution from the beginning. In other words, a positive voltage pulse on this pin resets the microcontroller.

Pins10-17: Port 3 Similar to port 1, each of these pins can serve as universal input or output. Besides, all of them have alternative functions:Pin 10: RXD Serial asynchronous communication input or Serial synchronous communicationoutput.

Pin 11: TXD Serial asynchronous communication output or Serial synchronous communication


Pin 12: INT0 Interrupt 0 input

Pin 13: INT1 Interrupt 1 input

Pin 14: T0 Counter 0 clock input

Pin 15: T1 Counter 1 clock input

Pin 16: WR Signal for writing to external (additional) RAM

Pin 17: RD Signal for reading from external RAM

Pin 18, 19: X2 X1 Internal oscillator input and output. A quartz crystal which determines operating frequency is usually connected to these pins. Instead of quartz crystal, the miniature ceramics resonators can be also used for frequency stabilization. Later versions of the microcontrollers operate at a frequency of 0 Hz up to over 50 Hz.

Pin 20: GND Ground

Pin 21-28: Port 2 If there is no intention to use external memory then these port pins are configured as universal inputs/outputs. In case external memory is used then the higher address byte, i.e. addresses A8-A15 will appear on this port. It is important to know that even memory with capacity of 64Kb is not used (i.e. note all bits on port are used for memory addressing) the rest of bits are not available as inputs or outputs.Pin 29: PSEN If external ROM is used for storing program then it has a logic-0 value every time the microcontroller reads a byte from memory.

Pin 30: ALE Prior to each reading from external memory, the microcontroller will set the lower address byte (A0-A7) on P0 and immediately after that activates the output ALE. Upon receiving signal from the ALE pin, the external register (74HCT373 or 74HCT375 circuit is usually embedded) memorizes the state of P0 and uses it as an address for memory chip. In the second part of the microcontrollers machine cycle, a signal on this pin stops being emitted and P0 is used

for data transmission (Data Bus). In this way, by means of only one additional (and cheap) integrated circuit, data multiplexing from the port is performed. This port at the same time used for data and address transmission.

Pin 31: EA By applying logic zero to this pin, P2 and P3 are used for data and address transmission with no regard to whether there is internal memory or not. That means that even there is a program written to the microcontroller, it will not be executed, the program written to external ROM will be used instead. Otherwise, by applying logic one to the EA pin, the microcontroller will use both memories, first internal and afterwards external (if it exists), up to end of address space.

Pin 32-39: Port 0 Similar to port 2, if external memory is not used, these pins can be used as universal inputs or outputs. Otherwise, P0 is configured as address output (A0-A7) when the ALE pin is at high level (1) and as data output (Data Bus), when logic zero (0) is applied to the ALE pin.

Pin 40: VCC Power supply

2.2.3 Architecture of 8051 Microcontroller

Fig :2.2.3 Architecture of 8051 Microcontroller2.2.4 Block diagram:

Fig:-2.2.4 Block Diagram of 8051 Microcontroller

2.2.5 Micro Controller-AT89S52

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 Atmels high-density nonvolatile memory technology and is compatible with the industry- standard 80C51 instruction set and pin out.

2.2.6 Features

8K Bytes of In-System Programmable (ISP) Flash Memory

Endurance: 1000 Write/Erase Cycles

4.0V to 5.5V Operating Range

256 x 8-bit Internal RAM

32 Programmable I/O Lines

Full Duplex UART Serial Channel

Fully Static Operation: 0 Hz to 33 MHz

2.3 LCD (Liquid Crystal Display)

LCDs are available to display arbitrary images (as in a general-purpose computer display) or fixed images which can be displayed or hidden, such as preset words, digits, and 7-segment displays as in a digital clock. They use the same basic technology, except that arbitrary images are made up of a large number of small pixels, while other displays have larger elements.

LCDs are used in a wide range of applications including computer monitors,

HYPERLINK "" televisions,

HYPERLINK "" instrument panels,

HYPERLINK "" aircraft cockpit displays, and signage. They are common in consumer devices such as video players, gaming devices, clocks

HYPERLINK "" watches,

HYPERLINK "" calculators, and telephones, and have replaced cathode ray tube (CRT) displays in most applications. They are available in a wider range of screen sizes than CRT and plasma displays, and since they do not use phosphors, they do not suffer image burn-in.LCDs are, however, susceptible to image persistence.The LCD screen is more energy efficient and can be disposed of more safely than a CRT. Its low electrical power consumption enables it to be used in battery-powered electronic equipment. It is an electronically modulated optical device made up of any number of segments filled with liquid crystals and arrayed in front of a light source

HYPERLINK "" (backlight) or reflector to produce images in color or monochrome. Liquid crystals were first discovered in 1888. By 2008, annual sales of televisions with LCD screens exceeded sales of CRT units worldwide, and t