Iowa State University-Senior Design

FM Transmitter

Project Plan

Project Team: Dec06-01

Client

Iowa State University-Senior Design

Faculty Advisor

Dr. John W. Lamont

Prof. Ralph E. Patterson III

Team Members

2

Grant Blythe

Tony Hunziker

Luke Erichsen

Jacob Sloat

2

Disclaimer Notice:

This document was developed as a part of the requirements of an electrical and computer engineering course at Iowa State University, Ames, Iowa. This document does not constitute a professional engineering design or a professional land surveying document. Although the information is intended to be accurate, the associated students, faculty, and Iowa State University make no claims, promises, or guarantees about the accuracy, completeness, quality, or adequacy of the information. The user of this document shall ensure that any such use does not violate any laws with regard to professional licensing and certification requirements. This use includes any work resulting from this student-prepared document that is required to be under the responsible charge of a licensed engineer or surveyor. This document is copyrighted by the students who produced this document and the associated faculty advisors. No part may be reproduced without the written permission of the senior design course coordinator.

Date Submitted

February 10, 2006

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Table of Contents

List of Figures iii

List of Tables iv

List of Definitions v

1. Introduction Materials 1

1.1 Abstract 1

1.2 Problem Statement 1

1.2.1 Problem Statement 1

1.2.2 Problem Solution 2

1.3 Operating Environment 2

1.4 Intended User(s) and Intended Use(s) 2

1.4.1 Intended User(s) 2

1.4.2 Intended Use(s) 2

1.5 Assumptions and Limitations 3

1.5.1 List of Assumptions 3

1.5.2 List of Limitations 3

1.6 Expecting End-Product and Other Deliverables 3

2. Purposed Approach and Statement of Work 4

2.1 Proposed Approach 4

2.1.1 Functional Requirements 4

2.1.2 Constraint Considerations 5

2.1.3 Technology Considerations 5

2.1.4 Technical Approach Considerations 6

2.1.5 Testing Requirements Considerations 6

2.1.6 Security Considerations 6

2.1.7 Safety Considerations 7

2.1.8 Intellectual Property Considerations 7

2.1.9 Commercialization Considerations 7

2.1.10 Possible risks and risk management 7

2.1.11 Project proposed milestones and evaluation criteria 8

2.1.12 Project tracking procedures 9

2.2 Statement of Work 10

2.2.1 Task 1 – End-Product Problem Definition 10

2.2.2 Task 2 – Technology Considerations 11

2.2.3 Task 3 - End-Product Design 12

2.2.4 Task 4 - End-Product Implementation 13

2.2.5 Task 5 - End-Product Testing 14

2.2.6 Task 6 - End-Product Documentation 15

2.2.7 Task 7 - End-Product Demonstration 16

2.2.8 Task 8 - Project Reporting 17

2.3 Estimated Resources and Schedules 19

2.3.1 Personal Effort Requirements 19

2.4 Other Resource Requirements 20

2.5 Financial Requirements 21

2.6.1 Schedule of Tasks 22

3. Project Team Information 23

3.1 Client 23

3.2 Faculty Advisor 23

4. Closing Summary 25

5. References 26

List of Figures

Figure 1: Gantt chart of expected project time flow ............................................... 22

Figure 2: Gantt chart of deliverables schedule…………………………………… 22

List of Tables

Table 1: Project Milestones and Overall Importance .......................................... 9

Table 2: Milestone Evaluation Criteria ............................................................... 9

Table 3: Personal Effort Time Table ................................................................... 19

Table 4: Other Costs ............................................................................................ 20

Table 5: Product Cost Analysis ........................................................................... 21

List of Definitions

FCC: Federal Communication Commission

Gantt chart: a schedule showing the specific tasks of a project, start dates, and completion dates.

LCD: liquid crystal display

MP3 player: digital music player, (i.e. ipod)

Satellite radio: subscription radio signal sent via satellite, (i.e. XM radio, Sirius radio)

Wall wart: AC power transformer designed to plug into a standard wall outlet

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1. Introduction Materials

This section will introduce the project, including the abstract, acknowledgements, problem statement and solution, operating environment, intended users and uses, limitations and assumptions, expected end-product and other deliverables.

1.1 Abstract

The objective of this project is to design a FM transmitter that will connect to a standard headphone output jack of an mp3 player and transmit the output to a car or home radio. The transmitter requirements are

· Transmit a minimum of 12ft

· Transmit between frequencies of 88MHz to 108MHz

· Have 4 programmable preset buttons

· Receive power from a 12V DC source

· And other client specified functions

The team will work to implement these requirements is the most efficient and cost effective way they find possible.

1.2 Problem Statement

The problem statement is broken up into two separate sections; one that defines the general problem area and another that describes the proposed approach to the solution.

1.2.1 Problem Statement

The problem calls for a device that will receive an input signal and broadcast it on the FM band. The device is to receive its signal input from the headphone jack of an MP3 player or output jack of an Satellite Radio and its power input from the 12V DC cigarette lighter/power socket in an automobile or 120V AC outlet from a house. It should be easily tunable to transmit on any desired frequency in the FM band (88-108 MHz) with the ability to preset four selectable frequencies within this range. The minimum transmission distance is to be at least twelve feet. It should recognize when there is an input signal and turn itself on automatically and automatically turn itself off after one minute if the input signal is absent.

1.2.2 Problem Solution

The proposed solution to this problem is a FM transmitter. This transmitter should accept power from three types of sources. Two of which would be adaptors that plug into the same input on the device. These adapters would include a “wall wart” and a cigarette lighter outlet adapter. The third source would be some variety on internal battery. The FM transmitter would modulate the signal, send it through an amplifier, and finally through an internal antenna. An internal memory source would store the four programmable station presets from the frequency band. An LCD screen would display the current frequency transmitting. This LCD could be backlit for easy night use. The stations would be accessible through a button/knob interface that also could include some lighting system. There would be a logic circuit or microcontroller in order to access memory, automatic turn off/on function, possible lighting, display frequency, and any other controlling concerns.

1.3 Operating Environment

The finished device will operate within a personal vehicle or a household room. The normal conditions for which would be a smaller space that could be potentially exposed to moisture, dust, dirt, and overall reckless negligence. It could be exposed to rougher conditions as being moved from location to location.

1.4 Intended User(s) and Intended Use(s)

This section is divided into two parts, one to cover the intended user(s), and the second is to cover the intended use(s).

1.4.1 Intended User(s)

The intended user for this product is anyone owning MP3 players or satellite radio devices. This is not exclusive to age, size, sex, or handicap. It does assume the amount of operating knowledge associated with MP3 player/satellite radio users.

1.4.2 Intended Use(s)

The FM transmitter is intended to make personal music players more accessible to listen to through home and car stereos. It should do so in a cost efficient and highly functional design.

1.5 Assumptions and Limitations

This section contains the assumptions and limitations of the project.

1.5.1 List of Assumptions

This is the list of assumptions that will be considered in the design.

· The transmitter will be used for all varieties of personal music players.

· The transmitter will be used in more locations than the personal home and car.

· The transmitter could be used at all hours of the day.

· Similar products will come directly from the personal music players producers as competition.

1.5.2 List of Limitations

This is a list of limitations that are inherent in the design preventing it to function in certain ways.

· The cost to purchase this product must not become uncompetitive.

· The transmitter must conform to FCC regulations.

· The frequency band must stay within 88-108 MHz.

· The power used by the device must be obtained from 120V AC and 12V DC.

· The size of the device must be a manageable size for ease of transportation and storage.

· There must be at least 4 programmable preset broadcast frequencies.

· The device must transmit at least 12 feet.

· Frequency must be tunable.

· Frequency must be displayed.

· The size shall not exceed 6 in. by 6 in. by 3 in.

· The max weight shall be less than 1 lb.

1.6 Expecting End-Product and Other Deliverables

The end product shall be a small handheld device to carry on ones self for use with their personal music player. It shall be taken in the car or used at home to allow a person to easily listen to their personal music player on any FM radio via FM transmission. The device shall have easy to use input/output interface with an easy to read display.

This device shall come with an adaptor for American standard wall outlet to avoid the use of the battery. This will be a simple wall wart device.

The transmitter will also come with an adaptor for the standard cigarette outlet for automobile use. This is to avoid the use of battery power as well. This will be a smaller device similar to a wall wart.

An instruction manual will also be included. This will describe the basic operations to the user.

The device and accessories should be deliverable by December 2006.

2. Proposed Approach and Statement of Work

This section will describe the proposed approach for solving the problem and a statement of work following the proposed approach.

2.1 Proposed Approach

This section will explain the methods for completing this project. The approach and design of this project will be split into the following four sub-sections; technical approach, technical design, testing descriptions, risk and risk management.

2.1.1 Functional Requirements

The following functions will be implemented into this project and are required to complete this project successfully. These primary requirements were specified by the client as well as the faculty advisor.

· Transmit audio through frequency modulation on the FM bands (88-108MHz).

· Turn off and on automatically according to the existence of an input signal.

· Work at a distance of at least twelve feet.

· Have 4 programmable frequency presets.

· Include inputs for MP3 player and satellite radio.

· Operate on a 12 volt DC source.

· Designed to ease handling in the car.

· Possible lighting for night time use.

· Possible battery for temporary outdoor use.

· The transmission frequency shall be displayed.

Note: These are the primary design goals of this project. Changes may occur later during the design and implementation process. Functional applications may also be added to improve the quality and market appeal of the product.

2.1.2 Constraint Considerations

These constraint considerations were developed from the limitations and assumptions. The entire project will be designed and constructed to perform under the following conditions and constraints.

· Relative size: The size of this design is not under strict observation, yet should be a reasonable size for portability.

· Broadcast regulations: The FCC has regulation broadcast strength of .1kW. The transmitter must not exceed this strength.

· Power requirements: The system will be required to operate on a standard 120 volt wall outlet as well as a car cigarette outlet. The system could possibly be designed to operate off of battery power when neither of the two previous methods mentioned are applied. The consumption of power does not have a limit although; it should be within reason for a car during weaker battery moments.

· Budget considerations: The project budget may not exceed $150 as described in the project description. The cost of programming and labor is not included. The final market cost ideally should not exceed $40.

2.1.3 Technology Considerations

There are many different proposed ideas on which technologies are best suited for this project. The major concerns for this section are the methods for amplification, antenna design, and logic controllers.

· Amplification: There are primarily two type of amplification used in audio electronics. The first is steady state; the use of a transistor to amplify the signal. This is cheaper, smaller, and is much more portable. The second of which is tube technology. This would use vacuum tube as the amplifying device. This is not very portable but provides better clarity of signal during amplification.

· Antenna design: This technology is important to the transmitter due to how effective different designs are at transmitting their signals. It must remain internal as to not take up space, yet provide adequate coverage area. The effective usage of power is important to this project.

· Logic controllers: Logic controllers are needed to save/retrieve station frequencies for preset use, run the LCD, and run the automatic on/off detection. This can be taken care of by personal designs or can be used by programmed microcontrollers. Both accomplish the task at hand. The personal designs would be more labor intensive. The microcontroller would be more expensive.

2.1.4 Technical Approach Considerations

The use of a FM transmitter requires a large consideration on the technology of the control circuits and the actual broadcast. The technologies being considered include steady state amplification, tube amplification, microcontrollers, and custom logic circuits.

2.1.5 Testing Requirements Considerations

The methods for testing and the criteria for acceptance will be discussed here. Testing is another consideration that should not be overlooked. This project will be tested by the following means

· Testing of amplifier: The ability to successfully amplify the signal to the desired strength without distortion. This will use simulation as well as physical testing.

· Testing of transmission: The antenna as well as the amplifier will be tested together to see how successful it is at transmitting data over an array of distances and frequencies.

· Testing of powering scheme: This test will be a physical test of how steady of a power source received from the two different adaptors as well as the automatic powering function that depends on the input jack.

· Testing of control circuits: The control circuits will go through a simulated test of all the possible functions to see the response. This test will be repeated as a physical test to assure that the controlling device is working properly.

· Client testing: The final product will undergo a demonstration of its features step by step in front of the client.

2.1.6 Security Considerations

There are no major security concerns with the development of this project other than keeping adequate documentation and keeping this documentation in the hands of project members and clients only.

The only security consideration with use of this product is keeping the power of transmission within the FCC regulation. This could cause a breach of secure broadcasts with the user as well as other broadcasters.