ECE 481 Design Project

Automated Print Quota Payment Device



Print quota Access With Speed

Final Project Report

Sean Korb and Kent Voorhees

April 26, 1996

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The PAWS system is designed to be a convenient way for students at NCSU to increase their printer quota. Set up as a vending machine, PAWS provides 24 hour access to a user's printer quota.

A user need only approach the PAWS machine, identify themselves using their student ID number through a numeric keypad, and insert a $5 bill. PAWS give feedback to the user through a 16x2 character display.

The paws machine interfaces to NCSU's Eos/Unity computer network, using system calls to the lpquota command and accesses a SQL database containing user names and student ID numbers. Interface is accomplished by sending and receiving commands to a dedicated workstation via RS-232 serial line. PAWS control is accomplished with a Motorola MC68HC711E9 development board.

The PAWS system is complete, but some security issues will need to be resolved before a generic daemon can be developed and PAWS can be installed for student use.

Table of Contents

1: Problem Description

1.1: Overview

1.2: Background

2: Project Analysis

2.1: Security

2.2: Maintainability

2.3: Usability

3: Design Considerations

3.1: Processing Platform

3.2: Host Server

4: Design Decisions and Implementation

4.1: The 68HC711 Micro-controller

4.2: Interface of PAWS to Eos

4.3: Function of PAWS

4.4: Activity of the PAWS Host Server

4.4.1: Simulation of lpquota command and SQL database

4.4.2: The PAWS Host Program

4.5: Maintenance and Service to the PAWS System

5: Observations and Conclusions

6: Installation of PAWS on the Eos/Unity Network

7: Credits


Appendix A Newsletter Article

Appendix B Hardware Description (courtesy R. Wigley and D. Creech)

Appendix C Source Code for PAWS Server

Appendix D Source Code for MC68HC11

Appendix E lpquota Simulator Source Code

Appendix F Cash Inventory Program Source Code