An-Najah National University Faculty of Engineering Computer Engineering Department

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An-Najah National UniversityFaculty of
EngineeringComputer Engineering Department
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Computerized Gas station
Graduation Project

• Prepared By
• Muhammad Addas
• Ramez Dmaidi
• Supervised By
• Dr- Loai Malhes

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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.

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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.

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Hardware Diagram
Simulation
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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.

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1. Keypad to interface card reader we need to save
   the pins of the pic so we choose the following
   design of keypad

• 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.

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Encoder Connection
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Pump Circuit
We use 7407 to drive the pump as it requires high
current and the relay to isolate the pump from
the PIC
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The Serial Diagram
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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 .

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Software Flow Chart
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Problems

• Card Reader not available specially programmer.
• Encoder takes alot of time to find it.
• Pump needs a lot of current.

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FINALLY

• Thanks to all