A Secure Wireless Interface between Personal Digital Assistants (PDAs)

Project Design Report

Team Dec02-07

ClientMotorola

Team MembersMichael HaleDavid Inman

Jeremy KohlhaasHassan Rashid

Faculty AdvisorsDr. James Davis

Dr. Douglas Jacobson

Date Submitted: 5/7/2002

Table of Contents

PageList of Figures iiList of Tables iiiAbstract 1Acknowledgements 21 Introduction 3

1.1 General Background 31.2 Technical Problem 31.3 Operating Environment 31.4 Intended Users and Uses 41.5 Assumptions 41.6 Limitations 41.7 Product Visuals 5

2 Design Requirements 62.1 Design Objectives 62.2 Functional Requirements 62.3 Design Constraints 62.4 Measurable Milestones 7

3 End-Product Description 84 Approach and Design 9

4.1 Technical Approaches 94.2 Technical Design 114.3 Testing Description 114.4 Risks and Risk Management 124.5 Recommendation for Continued Work 12

5 Financial Budget 136 Personnel Effort Budget 147 Project Schedule 158 Project Team Information 169 Summary 1710 References 18

List of Figures

PageFigure 1.1 PDA and Talkabout Visuals 5Figure 4.1 Visor Deluxe Cradle Interface Pinout 10Figure 7.1 Spring and Fall 2002 Gantt Chart 15

List of Tables

PageTable 5.1 Financial Budget 13Table 6.1 Original Personnel Effort Budget 14Table 6.2 Revised Personnel Effort Budget 14

Abstract

The objective of this project is to develop a wireless interface between two personal digital assistants (PDA) using Motorola Talkabout handheld radios. The interface will be designed to both maximize data rate and minimize overall cost. Furthermore, all information being transmitted should be secure from interception. The final product will include hardware to couple each PDA/Talkabout pair, and software to handle connection setup and security. During the testing phase, a third PDA/Talkabout combination could be used to attempt to intercept communication between the original pair to verify that a secure connection has been established. Upon completion of this project, an affordable wireless communication system between PDAs will be produced, providing mobile users with a simple way to share data.

Acknowledgements

The project team members would like to extend a special thank you to Motorola Incorporated for supporting the development of this project through the donation of equipment and resources. In particular, Mike Peterson, Robert Sanchez, and Erica Teichman are appreciated for their continual help throughout this project.

1 Introduction

The following section will provide a general background, define the technical problem, address the operating environment, consider intended users and uses, and examine assumptions and limitations of the project.

1.1 General Background

The goal of the project is to develop a wireless interface between two PDAs using two Motorola Talkabout radios. This project involves six major components: three Talkabout radios and three PDAs. Designed as companion products to personal computers, PDAs enable mobile users to manage their schedules, contacts and other critical personal and business information in a convenient and portable way. They can automatically synchronize their information with a personal computer using docking stations, or other connection methods. PDAs also offer many other applications, including spreadsheets, word processors, databases, financial management software, clocks, calculators and games. The goal of this project is to demonstrate secure wireless data communication between two PDAs via the Motorola Talkabout radios.

1.2 Technical Problem

Many technical problems must be addressed in this project. Maximization of the data rate between the two PDA devices is a big aspect as this affects the usability of the final product. Another obstacle to overcome is security, as the communication link between the PDA/Talkabout combinations must be a secure one. This could be demonstrated by incorporating a third wireless PDA/Talkabout set-up into the communication system and testing interception simplicity. However, at this time a third PDA has not been obtained; thus, other security testing methods possibly involving the use of a PC are being investigated. The interface between the devices must be inexpensive in regards to hardware purchase. While software development may run higher, connection hardware (cables, circuit boards, etc.) should be held close to a $20 per unit cost. Knowledge of PDA and Talkabout radio functionality must also be gained by the group to allow for educated programming, hardware connection, and security decisions.

1.3 Operating Environment

The Talkabout radio and PDA hardiness greatly play into their usability. The finished product will likely be susceptible to damage by outdoor elements, but no greater than that of the PDA or Talkabout radio. Since the PDAs and radios are portable (capable of autonomous operation), the finished product will also be easily transportable. The range of date transmission will be limited to that of the Talkabout radios. For the Talkabout model 6310 that is being used in this project, the range is 2 miles.

1.4 Intended Users and Uses

The end product will be used by consumers who are in need of quick data transmission between portable devices. This includes those whose jobs involve movement between various job sites, and those constantly far from an available personal computer. Large factory or warehouse managers could also easily exchange information without having to leave the floor for extended periods. This would allow for savings in time spent commuting to and from personal computers throughout the day, saving companies the expense of unnecessary tasks.

1.5 Assumptions

1. The Talkabout radio expense and other costs involved will be covered by the client.

2. All other major expenses related to the project will be paid for by the ECpE department at Iowa State University. The poster is not considered to be a major expense, and will be paid for by team members.

3. Motorola will fabricate the hardware necessary for connecting each PDA/Talkabout pair.

4. Specifications for the PDA’s serial connector and the Talkabout’s analog input will be obtainable.

5. Only two Talkabout radios will be involved in a communication session at any given time.

6. The maximum cable length between the PDA and Talkabout should not be an issue since they will be always be positioned next to each other.

1.6 Limitations

1. The amount of time available for completion of the project is limited to 2 semesters, specifically spring and fall 2002.

2. The Talkabout radios have a limited range of operation, 2 miles. At the present time, the specific model is the T6310. Other specifications have not yet been provided by Motorola.

3. See also the design constraints listed in section 2.3 of this document.

1.7 Product Visuals

Handspring Visor Deluxe Handheld Motorola TALKABOUT® T6310 Radio

Figure 1.1 PDA and Talkabout Visuals

2 Design Requirements

2.1 Design Objectives

The objective of this project is to develop a secure wireless interface connection between two PDAs using two handheld Talkabout radios. The design must include some type of encryption development to create a secure connection between the two PDAs. The fabrication of a component board will also be necessary for the connection between the PDAs and Talkabout radios.

2.2 Functional Requirements

When the project is completed, the team will expect to be able to make a secure wireless connection between the two PDAs using the Talkabout radios as a means of the connection. The PDAs will connect to the Talkabout radios via a serial port and/or other connection methods. The software must enable encryption of the data to create a secure line of communication. Furthermore, the entire finished product must be portable and lightweight, to complement the portability of the PDAs.

2.3 Design Constraints

Several design constraints are involved with this project. They include:

1. Weight – All components used must be lightweight. This means that the finished product’s weight will be comparable to that of the PDA and Talkabout radio alone.

2. Expense – Interface hardware should not exceed $20.3. Connections – Attachment of the PDA to the Talkabout radio should use available

ports or simple connections.4. Security – The communicated data between two PDA/Talkabout combinations

must be secure.5. Time – The project must be completed within the given time allotment.

2.4 Measurable Milestones

Specific milestones will be met throughout the development cycle. Each milestone will be considered a success if its associated goals (shown below) are met.

1. Design – Completion of a specific plan for implementing the project.2. Hardware – Establishment of a link which will permit the transmission of data

between the PDA and Talkabout radio.3. Software – Finalization of the software to pass data between the PDA/Talkabout

radio setups.4. Security – Resistance to interception of data by third parties. This could be

verified using a third setup (using a PC if a third PDA is not available).5. Testing – Successful evaluation of the implemented hardware and software.6. Demonstration – Successful public exhibition of the completed product.7. Documentation – Complete records of all relevant information pertaining to the

project.

3 End-Product Description

Iowa State University is proud to announce the future availability of a secure wireless interface for PalmOS-based PDAs, using Motorola Talkabout radios. This will allow simple long-distance communication between two PDAs, while also using encryption to protect the integrity of the transmitted information. The product will include special hardware to connect the PDA to a Talkabout radio, as well as software that manages this connection. The project is being developed for Motorola Incorporated, and will be operable in December 2002.

4 Approach and Design

4.1 Technical Approaches

To successfully enable communication between PDAs, two main components will need to be developed; namely, hardware to couple each PDA to a Talkabout radio, and software to handle communication and security.

Hardware must be produced to connect the digital serial interface of each PDA to the analog interface of a radio. One key goal of the client is to keep this component inexpensive. Two different approaches are available in considering this issue. The first is to attempt to obtain a modem from a PDA producer, such as Palm or HandSpring, at a discounted rate. It is likely, however, that either the vendors will be unable to provide discounted modems, or the modems will turn out to be inadequate for the project at hand. In this case, a second approach is to design and fabricate a custom interface. When possible, sample units of integrated circuits and other components will be used to help reduce costs; it is also possible that Motorola will be able to assist the acquisition of parts. Upon completion of the hardware design, three copies will be produced so software development can finish and system testing can begin. Motorola has offered to aid the fabrication of these boards.

Initial software development will begin before the production of final hardware. However, completion of some parts will not occur until the production of three working copies of the hardware interface. The purpose of this software will be to establish and manage the virtual connection between two PDAs, and to implement security. It remains to be investigated how much of this functionality is already present in the Palm operating system, but all missing parts will need to be implemented by the team. For security, it is likely that a suitable cryptosystem will need to be located and incorporated into the code. To enable software creation, a C/C++ compiler for PalmOS called CodeWarrior has been provided free of charge by MetroWerks, a Motorola subsidiary. The software development approach is to write as much as is possible before the completion of the hardware. Once the hardware production is complete, the software finalization and testing will occur.

The following is a copy of a page from a document on Handspring’s web site. It is listed in the References section of this document.

Figure 4.1 Visor Deluxe Cradle Interface Pinout

4.2 Technical Design

When reporting the actual design of the project, several major topics will be explained in detail. These include:

I. Hardware designA. Digital serial interface to PDAB. Analog interface to Talkabout radioC. Modulation circuitry

II. Software designA. User interface and PalmOS integrationB. Virtual connection managementC. Security implementation

Currently, no design work has been completed due to a lack of technical documentation from Motorola.

4.3 Testing Description

Throughout the design process, two main categories of testing will occur. The first is unit testing which happens while the hardware and software are being independently designed. The other category is system testing of the multiple hardware copies.

Unit testing of the hardware interface will primarily consist of a circuit board mock-up. Documentation, schematics, and electrical probing will determine the correctness of this sample board. Once it is operating as desired, three copies will be produced and verified in the same way.

Unit testing of the software will involve two main parts. First, the verification of the usability and operation of the PDA user interface is checked. For the second part of unit testing, if it is possible without much extra effort, two PDAs will be connected with a serial cable. This will bypass the custom hardware and radios, and allow testing of only the software. The temporary setup should assist examination of the software that establishes and maintains connections; however, it will not allow testing of error recovery mechanisms. Software unit testing will be considered successful if a person can operate the user interface to establish a connection and transmit data.

System testing will begin when three hardware samples have arrived. First, the ability to establish connections will be verified. Next, security will be examined. This could be done using a third PDA/Talkabout setup to try and intercept transmissions. Finally, the maximum data rate achievable will be determined. Any minor changes that can be made to increase throughput will be incorporated into the design.

4.4 Risks and Risk Management

1. The custom hardware interface must operate correctly. This will be the highest priority since the project completely depends on this piece. If hardware problems are encountered, they must be dealt with before the project can proceed any further.

2. Three copies of the hardware must be fabricated in time to finish software development and sufficiently test the completed setup. If problems with the hardware arise, they must be fixed before the project can progress.

3. The total custom hardware cost should be under $20 per unit. If this is not possible, then the only option will be to keep costs as low as possible using any methods available, and surpass $20 by as little as necessary.

4. Equipment may be ruined during development. While every precaution will be taken to avoid accidental destruction of PDAs, Talkabout radios, and custom circuit boards, the chance of this occurring still exists. If anything is destroyed, it will have to be replaced, at a significant expense of time and money.

5. A team member may be lost from the project. If this occurs, the only option will be to finish the project with the remaining team members.

4.5 Recommendation for Continued Work

The schedule for completing the actual hardware and software implementation is set for the coming fall semester. Work during the spring semester has primarily focused on the acquisition of components and specifications necessary for the successful completion of this project. No actual design was completed during the spring semester since the group has not received any specifications or Talkabouts from Motorola. The group has been requesting these since January, and will continue to do so until they are delivered. Upon receipt, product design will begin. It is the group’s current recommendation that this project continue based on the outline shown in the revised Gantt chart. Due to unexpected difficulties that may arise during hardware or software development, it is possible that the project will not be completed according to the planned schedule. However, every effort will be made to adhere to the time frame presented in this document.

5 Financial Budget

Original and revised financial budget plans are given below. The team will attempt to keep the final cost below the most recent estimate, but it is possible that this will not be feasible. Most major costs will be covered by Motorola and its subsidiary Metrowerks.

Table 5.1 Financial Budget

Item Original Estimated Cost Revised Estimated CostPalm Pilots $750 (qty 3) $200 (qty 2)Talkabout Radio * $150 (qty 3) $150 (qty 3)Palm OS Compiler ** $425 $500Board Fabrication * $1000 $1000Poster Cost $50 $45Programming Resources (books, etc)

$100 $100

Miscellaneous Cables, connections, etc

$150 $150

Total $2625 $2145

* costs covered by Motorola** costs covered by Metrowerks

6 Personnel Effort Budget

Original and revised personnel effort budget plans are given below. The team will attempt to meet these estimated hours as closely as possible, but it is possible that this will not be attainable.

Table 6.1 Original Personnel Effort Budget

Michael Hale

David Inman

Jeremy Kohlhaas

Hassan Rashid

Totals

Specific taskProject Planning 10 15 15 10 50Hardware design 25 35 50 25 135Software development 40 40 30 45 155Security testing 10 15 15 10 50Totals 85 105 110 90 390

Table 6.2 Revised Personnel Effort Budget

Michael Hale

David Inman

Jeremy Kohlhaas

Hassan Rashid

Totals

Specific taskProject Planning 10 15 15 15 55Hardware design 35 35 55 25 150Software development 45 45 25 45 160Security testing 15 15 15 15 60Totals 105 110 110 100 425

7 Project Schedule

This revised chart includes a schedule for both the spring 2002 and fall 2002 semesters.

Figure 7.1 Spring and Fall 2002 Gantt Chart

8 Project Team Information

Team Members

Michael Hale (CprE)4518 Steinbeck #3Ames, IA 50014(515) 268-3183mhale@iastate.edu

David Inman (CprE)4525 Steinbeck #4Ames, IA 50014(515) 292-8674djinman@iastate.edu

Jeremy Kohlhaas (EE)620 Lynn Ave Ames, IA 50014(515) 296-1755jer65@iastate.edu

Hassan Rashid (CprE)135 Dotson Dr #A32Ames, IA 50014(515) 292-8994hash@iastate.edu

Faculty Advisors

Dr. James Davis2413 Coover HallIowa State UniversityAmes, IA 50011(515) 294-0659(515) 294-8432 (FAX)davis@iastate.edu

Dr. Douglas Jacobson2419 Coover HallIowa State UniversityAmes, IA 50011(515) 294-8307(515) 294-8432 (FAX)dougj@iastate.edu

Client

Motorola IncorporatedPlantation, FloridaContacts:

Mike Petersen(954) 723-6806cmp007@email.mot.com

Robert Sanchez(954) 723-6366ers032@email.mot.com

Metrowerks CorporationContacts:

Erica Teichman(512) 997-4788ericat@metrowerks.com

9 Summary

The result of developing an affordable wireless communication interface for PalmOS-based PDAs will be a product that has applications in a wide range of settings. Both business and casual users are increasingly buying digital assistants; enabling them to easily transfer information within a short distance will be a valuable addition to their PDAs. The use of tried-and-true Talkabout radios for implementation of this solution will provide a sense of familiarity and trust about the capability of this end product that is being developed. The result will be a product that is built on traditional technology and has widespread uses in the marketplace.

10 References

1. Handspring Technical Reference Guide: Visor Handheld FamilyRelease 1.10. Available on the Handspring web site.

2. Motorola Talkabout web site: www.mot.com

3. Handspring Visor Deluxe web site: www.handspring.com