FM Transmitter

1. FM Transmitter Dec06-01

2. FM Transmitter Project Client: Iowa State University – Senior Design Team: Grant Blythe Luke Erichsen Tony Hunziker Jacob Sloat Advisors: Dr. John W. Lamont Prof. Ralph E. Patterson III

3. Project Overview Objective: Design a portable short range FM transmitter for use with MP3 players or satellite radios

4. Presentation Outline • Introduction • ProjectOverview • Problem Statement • Assumptions, Limitations, Requirements • Project Activities • Approach and Design • Implementation and Testing • Resources and Schedule • Conclusion

5. Definitions FCC: FM: LCD: MP3 player: Satellite radio: Transmission frequency: Federal Communications Commission frequency modulation, a method of modulating an audio signal for wireless transmission liquid crystal display portable digital music player, (i.e. ipod) subscription radio signal sent via satellite, (i.e. XM radio, Sirius radio) the frequency at which the device is transmitting the FM modulated signal to the FM radio.

6. Problem Statement • The objective of this project is to design a FM transmitter that will: • Connect to a standard headphone output jack of an mp3 player • Transmit a minimum of 12 ft • Transmit between frequencies of 88MHz to 108MHz • Have 4 programmable preset buttons • Receive power from a cigarette lighter/power socket • Have an automatic on/off function • Display the current transmission frequency

7. Operating Environment • The finished device will operate within a personal vehicle or a household room that could be exposed to: • Moisture • Dust/Dirt • Impacts • Temperatures from 32° - 100° F • Normal humidity/pressure

8. Intended Users/Uses Intended Users The intended user for this product is anyone owning a MP3 player or satellite radio device. Intended Uses The FM transmitter is intended to make personal music devices accessible through home and car stereos.

9. Assumptions • The device will receive a 20 Hz to 20 kHz input audio signal from all varieties of personal music devices. • The device will output to standard North American FM radio equipment. • The transmitter will be subjected to a variety of environments including varying temperatures, humidity, vibration levels, and electromagnetic noise. • The device will be operated in varying ambient light conditions. • The user will have access to a steady power source.

10. Limitations • The cost to purchase this product shall not become uncompetitive. • The transmitter must conform to FCC regulations. • Part 15 concerning unlicensed FM broadcasting • Broadcast strength: ≤0.1kW • Broadcast band: 88-108 MHz • The device shall be capable of obtaining power from readily available power sources. • The size shall not exceed 6 in. by 6 in. by 3 in. • The weight shall not exceed 1 lb.

11. Expected End Product • The device case will be made of plastic • The case will allow for easy hand manipulation and transportation • The device will implement an LCD screen displaying the transmission frequency. • The device will be accompanied by a user manual. • The user input interface will consist of six buttons. • “up” and a “down” button to adjust transmission frequency • 4 buttons will each access a programmable preset frequency • The device will be accompanied by a user manual.

12. Present Accomplishments • Problem Defined • Research Completed • Technologies Selected • Design Completed • Design prototyped • Prototype testing • Project documented Key Completed In Progress

13. Approaches Considered Logic Approach The logic for the transmitter could be implemented either with a microcontroller and software or with dedicated hardware logic.

14. Project Definition A successful project will result in a device that: • shall receive an input signal and broadcast it on the FM band • shall receive its signal input from a 3.5mm input port • shall accept power from a cigarette lighter/power socket of an automobile or a standard wall outlet • shall be capable of storing 4 programmable transmission frequencies • shall display the transmission frequency on a back-lit display

15. Research Activities FM Radio Transmission • Uses transmission band of 88-108 MHz • Signal Modulated onto carrier frequency • Backwards compatible with stereo/mono

16. Research Activities FCC Rules • Part 15 concerning unlicensed FM broadcasting • Broadcast strength: ≤0.1kW • Broadcast band: 88-108 MHz LCD Displays • Reflective technology • Transflective technology • Backlights

17. Design Activities Functional Diagram • Inputs • Processing • Outputs

18. Design Activities Microcontroller • PIC 16F877 • 28 Pin DIP • Non-Volatile Memory • I/O

19. Design Activities Signal Processor • Rohm BH1415F • SOP22 • Phase Locked Loop • Stereo Capability • Built in pilot tone • Serial communication with microcontroller

20. Design Activities Overall Schematic

21. Implementation Activities Component Communication • Serial Connection from microcontroller to signal processor

22. Implementation Activities Component Communication For Example: in the case of 99.7 MHz carrier frequency. 99.7 MHz / 100 kHz (fref) = 997  3E5 (HEX)

23. Implementation Activities Breadboard Implementation • Preliminary Implementation • Testing for functionality • Necessary modifications performed Schmartboard • Surface mount components • Allows for easy prototyping

24. Implementation Activities Microcontroller Software • Handles all device logic • Controls user interface • Data Connection to signal processor, LCD display • Controls backlighting PCB Implementation • Modified design • User testing • Commercialization of device

25. Testing/Modification Device Subsystem Testing • Testing of signal modulation • Testing of transmission • Antenna performs proper transmission (quality and strength) • Transmission occurs across frequency band • Power system tested for reliability • Control system tested for proper function Prototype Testing • Integration of all subsystems • Verifying prototype meets or exceeds all design requirements • User testing • Advisor/Client acceptance testing

26. Resources Personnel Efforts • 4 Team members first semester • 3 Team members second semester • Jacob Sloat studying abroad

27. Resources Project Finances

28. Resources Project Schedule

29. Conclusion • Problem Defined • Research Completed • Technologies Selected • Design Completed • Design prototyped • Prototype testing • Project documented Project Evaluation • Many objectives completed • Several tasks in progress • Expected full completion by December Key Completed In Progress

30. Conclusion Commercialization • Product market already exists • Several competitors established in market • Must provide unique features to compete Commercialization Finances • Expected consumer cost ≈ $30.00 • Expected production cost ≈ $15.00 • Profit Margin ≈ $15.00

31. Conclusion Recommendations for Additional Work • Commercialization of product • Expanded functionality -Auto-Seek Frequency -Multiple Input Sources -HD radio output Lessons Learned • Team worked well • Importance of maintaining schedule • Pad schedule to compensate for delays Delays will happen, Plan for them!

32. Conclusion Risk Management - Anticipated • Loss of team member • Delays in obtaining parts • Component failure Risk Management - Unanticipated • Complexity of technology • External commitments/responsibilities

33. Summary This project will result in an end product that is expected to not only perform the required functions, but prove to be a competitive model in the commercial market of FM transmitters. The goal is to have an end-product that proves to be unique within this already established market. This means not only having increased functionality, but having an appropriate cost and a mass producible design.