Department of Electrical & Computer Engineering

Preliminary Design Review

Team:Lucas RootTelin Kim

Brandon ThorpeMichael Shusta

Advisor:Professor Tessier

Outline

• Team and Roles• Statement of Problem • Existing Products and Our Solution• Basic Operation • Description of Main Components

Requirements Implementation

• Design Challenges• Deliverables for MDR

Department of Electrical & Computer Engineering

Team Organization

Project Lead:

Lucas Root

Software Development:

Brandon Thorpe

Hardware Development: Mike Shusta

Software & Web

Development: Telin Kim

Department of Electrical & Computer Engineering

Problem Statement

• Two step buying process

• Time spent in line

• Shoppers must carry a form of currency

• Theft

Department of Electrical & Computer Engineering

Existing Products

• RF and microwave tags

• Ink tags

• Grocery store self-checkout

Department of Electrical & Computer Engineering

Existing Products

Why BlueTag Is Better:

• Combines security and purchase• Products are not destroyed (consider ink)• Self-checkouts can be fooled (weight

manipulation, price substitution)

Department of Electrical & Computer Engineering

Our Solution: BlueTagCell phone based payment system coupled with

Bluetooth un-lockable security tags

Tag ID

Item Info

Locate and Connect

Request Unlock Code

Credit Card Purchase

Unlock Code

Unlock Code

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Client

Server

Internal Database

Inventory

Locked Item

System Overview

Department of Electrical & Computer Engineering

Primary Design Components• Bluetooth Security Tag• Cell Phone Software• Web Server

Department of Electrical & Computer Engineering

Security Tag Requirements Lock Mechanism • Reusable• Digitally controlled

Bluetooth Communication• Low power• On-board processing• Digital I/O

Power Delivery• Regulated voltage• Rechargeable and replaceable batteries• High transient current• Low power alert

Tag Identification• Software: hardcoded unlock key• Physical: tag ID on housing

Power

Mechanism

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Lock Mechanism• Spring-loaded or bi-directional solenoid with IC relay• DC motor, H-bridge, and gear and shaft

Security Tag Implementation

Department of Electrical & Computer Engineering

+V

-V

+V

-V

Bluetooth Module: AIRcable SMD• Wirelessly programmable micro-controller• Runs applications in BASIC on the AIRcable OS

Power• 50uA sleep, 11mA with connection, 25mA peek, max range peeks

up to 70mA at 5V

Memory• 512 k EEPROM, 6 Mb internal flash

Communication• Bluetooth Master/Slave connections• UART • 8 pin digital I/O • Two analog input

Security Tag Implementation

Department of Electrical & Computer Engineering

Cell Phone Software RequirementsUser interface

• ID code entry• Item display

Communication between phone and server• Item Identification• Unlock code request and receive

Communication between phone and tag• Tag identification• Unlock code transmit

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Development:• BlackBerry Plugin for Eclipse• Extensive RIM API’s

Phone to Server Communication:• TCP/IP based data transfer over WiFi

Phone to Tag Communication:• Full access to Bluetooth Serial Port Profile on

BlackBerry

Cell Phone Software Implementation

Department of Electrical & Computer Engineering

Cell phone Software: Program Flow

Start Program

User Type Number

Error?

Display Product Info

Confirm Purchase

Item Lookup and Identification

Purchase

Unlock Code Lookup

Tag Connect

Tag Unlock

Yes

Cell PhoneTag Server

No

No

Department of Electrical & Computer Engineering

Server RequirementsManage client requests

• Unlock code and item information requests

Query a store’s inventory database• Item lookup and identification

Complete purchase • Third party payment system such as Google

Checkout™

Department of Electrical & Computer Engineering

Server Implementation• The server will be written using C# and the

Microsoft .NET 2.0 framework for rapid development

• Interfacing with Google checkout will be done through the GCheckout .NET assembly provided by Google.

• The internal database will be implemented with MySQL 

Department of Electrical & Computer Engineering

Design Challenges and Limitations• Low power consumption• Hardware and software security• Mechanical integration• Small, fast, intuitive interface• Low cost

Department of Electrical & Computer Engineering

• Run simple routines on the AIRcable• Basic locking mechanism• Blackberry hello world• Database structure

Deliverables for MDR

Department of Electrical & Computer Engineering