An-Najah National UniversityAn-Najah National UniversityFaculty of EngineeringFaculty of Engineering

Computer Engineering DepartmentComputer Engineering Department

الرحيمالرحمناللهبسم

Computerized Gas stationComputerized Gas station

Prepared ByPrepared By

Muhammad AddasMuhammad Addas

&&

Ramez DmaidiRamez Dmaidi

Supervised BySupervised By

Dr- Loai MalhesDr- Loai Malhes

Graduation Project

Introduction

In this project we tried to design full computerized Gas station without employees in station, this station is one of multiple networked units.

Each unit is connected serially with PC In which enough information about customers available including account number and balance.

The customers enter account number, the computer in that station checks for valid account and sends back the result to PIC.

If the account valid the user enter the number of liters wanted.

Objectives

1) No need for the worker in each station.

2) The system will work until the amount that entered finished.

3) Security, each user has account number.

4) The price updated by the centralized server daily.

Hardware Diagram

Microcontroller PIC 16F877

Keypad

LCD

Relay

PumpSerial

PC

SimulationSimulation

Hardware Components

1) PIC16F877 : we choose it because we are familiar and available in the market with suitable price.

2) LCD : 16 char one line LCD.

3) pump : 12V.

4) Relay: 12 v.

5) Buffer to drive Relay 7407.

The buttons are debounced by hardware.

Then the buttons are interfaced to 8-3 active low

encoder we need two encoders for 12 buttons.

Then the output of them is fed to PIC.

6) Keypad: to interface card reader we need to save the pins of the pic so we choose the following design

of keypad:

Encoder Connection

1 2

1KΏ

Vcc = 12

From PIC c3

Relay

To Pump

7407

Pump Circuit

We use 7407 to drive the pump as it requires high current and the relay to isolate the pump from the PIC

The Serial Diagram

+ 1u

U1

ICL232

12

14710

11

138 9

13

45

26

R1OUT

T1OUTT2OUTT2IN

T1IN

R1INR2IN R2OUT

C1+C1-

C2+C2-

V+V-

C7

C6

+ 1u

594837261

+ 1u

+ 1u

Serial And PIC Interconnection The project based on using a Card Reader to handle he money

payment ,but cause of the lack of these resources we replace the Card Reader with the a PC control using the serial port.

The PIC controller gets the account number from an external keypad and send it thought the serial port to be handled by a Visual C+

+ program.

The program checks the account number and send the balance for this customer to the PIC, then gets the number of litters to be pumped.

The program performs the calculations related to the balance and returns the new value to be displayed on the LCD.

A daily update is done for the price value .

Software Flow Chart

Serial

Test Account

Start

Initialization

Read Account Get Balance

Price

#Of liters

Pump 0 1

Problems

Card Reader: not available specially programmer.

Encoder: takes alot of time to find it.

Pump needs a lot of current.

FINALLYFINALLY

Thanks to all…Thanks to all…