FM Transmitter Dec06-01 Advisors:Dr. John W. Lamont Prof. Ralph E. Patterson III Client:Iowa State...
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Transcript of FM Transmitter Dec06-01 Advisors:Dr. John W. Lamont Prof. Ralph E. Patterson III Client:Iowa State...
FM TransmitterDec06-01
Advisors: Dr. John W. Lamont
Prof. Ralph E. Patterson III
Client: Iowa State University - Senior Design
Team: Grant Blythe Tony Hunziker
Luke Erichsen
Date: December 5, 2006
Introduction
Introductory Material
Project Activities Design
Implementation
Resources and Schedules
Conclusion
Presentation Outline
Objective:Design a portable short range FM transmitter for use with MP3 players or satellite radios
Project Overview
Definitions
FCC:
FM:
LCD:
MP3 player:
PLL:
RF:
Transmission frequency:
VCO:
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)
phase-lock loop
radio frequency
the frequency at which the device is transmitting the FM modulated signal to the FM radio
voltage controlled oscillator
Acknowledgement
The team would like to thank the following people for their help and support.
Jason Boyd:For showing us various possibilities for prototyping surface mount components.
Dr. John W. Lamont and Prof. Ralph E. Patterson III:For your knowledge and guidance in helping us with part selection and referring us to expert advice when needed.
Dr Geiger:For help understanding the phase lock loop
Fredo:For a helpful reference.
Yesuratnam Thommandru:For help uderstanding programming PIC’s
Problem Statement
Currently many people use MP3 players and satellite radios, but do not have a way to connect them to their other audio equipment. 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.
General Problem Statement:
General Solution Approach:Most of this existing equipment has FM radio capabilities, so the solution approach was to develop a portable FM transmitter to link MP3 players and satellite radios to any FM receiver.
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
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.
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.
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: ≤ 0.1W 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.
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
Transmit a minimum of 12 ft
Present Accomplishments
Problem Defined Successfully completed
Research Completed Successfully completed
Technologies Selected Successfully completed
Design Completed Successfully completed
Design prototyped Completed
Prototype testing Partially completed
Project documented Successfully completed
Approaches Considered
Microcontroller/Software Hardware Logic Advantage
Cost ≈$7.00 ≈$7.00 none
Ease of Implementation
Requires software to be written, compiled and loaded
Requires detailed design and intricate implementation with more components
Microcontroller
Weight/Size One large IC Several small components
none
Expandability & Modifiability
Requires software to be changed and recompiled
Requires full redesign of entire circuit
Microcontroller
Logic Approach
The logic for the transmitter could be implemented either with a microcontroller and software or with dedicated hardware logic.
Approaches Considered
VIM - 404 VI - 415 Advantage
Cost ≈$5.00 ≈$10.00 VIM - 404
Ease of Implementation
Controlled by three 1/3 duty cycle signals as common inputs.
Controlled by multiple drivers which receive binary input.
VI - 415
Number of Pins 20 40 VI - 404
Display Approach
Due to self-imposed assumptions, transflective LCD’s were only considered. Transflective LCD’s allow data to be viewed with and without a backlight.
Approaches Considered
Assembly C Advantage
Ease of Implementation
Closer to machine language. Requires writing to specific registers.
Abstract language that is more user friendly.
C
Memory Space Allows more control for memory use.
The compiler yields less efficient memory use in translation.
Assembly
Group Understanding
Minimal practice, unfamiliar with commands.
More familiar with commands.
C
Programming Approach
It was possible to program the PIC in two different languages. The two different languages were Assembly or C.
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
Research Activities
FM Radio Transmission Uses transmission band of 88-108 MHz Signal Modulated onto carrier frequency Backwards compatible with stereo/mono
Research Activities
FCC Rules
Part 15 concerning unlicensed FM broadcasting
Broadcast strength: ≤ 0.1 W
Broadcast band: 88 -108 MHz
LCD Displays
Reflective technology
Transflective technology
Backlights
Design Activities
Functional Diagram
Inputs
Processing
Outputs
Design Activities
Microcontroller PIC 16F877 28 Pin DIP Non-Volatile Memory I/O Handles all device logic Controls user interface Data connection to signal
processor, LCD display Controls backlighting
Design Activities
Signal Processor Rohm BH1415F SOP22 Phase Locked Loop Stereo Capability Built in pilot tone Serial communication
with microcontroller
Design Activities
Design Activities
Overall Schematic
Design Activities
Component Communication
Serial Connection from microcontroller to signal processor
Design Activities
Component Communication
For Example: in the case of 99.7 MHz carrier frequency.
99.7 MHz / 100 kHz (fref) = 997 3E5 (HEX)
Implementation Activities
Changes From Original Design
• LCD display
• Switched to VI – 415 from VIM – 404 because of ease of connecting to PIC.
• Clock
• Switched from a clock to a ceramic resonator.
• Serial connection
• Used output pin instead of serial connection.
Implementation Activities
Problems
• PIC
• Problems getting compilers installed and working in senior design labs. Solved by downloading free compiler online and bugging the Computer Support Group.
• Problems getting PIC to work. Initial registers were not initialized. Once watchdog timer, code-protection, and low – voltage program were disabled and the clock type was selected, PIC worked.
• Transmitter Circuit
• Problems getting the output signal. Solved by enabling the transmitter chip.
Implementation Activities
How Implementation Process Can Be Improved
• Make sure all necessary programs were installed before needed.
• Read all documentation on device.
• Schedule extra time for delays
Testing/Modification
Device Subsystem Testing Testing of signal modulation
Test composite signal generation Test RF oscillator
Test output power 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
Testing/Modification Results
Device Subsystem Testing Results Testing of signal modulation
Composite signal generates successfully RF voltage controlled oscillator does not initialize
Testing output power Output ≈ .085 W which is less than FCC broadcast strength of .1 W
Control system tested for proper function I/O control works successfully
Prototype Testing Results Integration of all subsystemsVerifying prototype meets or exceeds all design requirements
RF VCO failure causes transmission system failure Advisor/Client acceptance testing
Not completed
Resources
Personnel Efforts 4 Team members first semester 3 Team members second semester
Jacob Sloat studying abroad235
137
227 232
0
50
100
150
200
250
Grant Jacob Luke Tony
Personnel Ef f orts
Resources
Financial Requirements
$100
$12
$23
$15
$35
Parts
Printing &Binding
Poster
Case
PCB
`
Project Finances
Resources
J F M A M J J A S O N D
Final Documentation
Final Product Testing
Final Product Implementation
Prototype Testing
Prototype Implementation
Finalization of Design
Design Research
Problem Definition
Project Schedule
Project Evaluation
Milestone Evaluation Criteria
Evaluation Result Numerical Score
Exceeded/Met 90% +
Partially Met 1 - 89%
Did not Meet Standard 0%
Project Evaluation
Milestones
Relative Importance
Evaluation Score
Resultant Score
Problem definition 15% 100% 15
Research 10% 100% 10
Technology selection 10% 100% 10
End-product design 15% 100% 15
Prototype implementation 10% 70% 7
End-product testing 10% 70% 7
End-product documentation 10% 95% 9.5
Project reviews 5% 100% 5
Project reporting 10% 100% 10
End-product demonstration 5% 50% 2.5
Total 100% 91%
Previously defined passing score = 80%
Commercialization / Additional Work
Commercialization
Product market already exists Several competitors established in market Will be difficult to establish in market Must provide unique features to compete
Recommendations for Additional Work
Commercialization of product Expanded functionality
Auto-Seek frequency to broadcast on Multiple input sources HD radio output
Lessons Learned
What went well?
Team member interaction Programming (after initial configuration error) Documentation
What did not go well?
Configuring PIC programmer Transmission circuit debugging Device implementation
Lessons Learned
Knowledge gained
FM modulation process Microcontroller programming LCD display drivers Soldering skills
What would we change?
Make sure necessary programs were installed before needed Talk to someone with background in RF Have a computer engineer on the team Project schedule
Risk Management
Anticipated Potential Risks
Risk: Loss of a team member
Management: Increase remaining members efforts
Risk: Component Failure
Management: Ordered multiples of the less common components
Risk: Delay Receiving Parts
Management: Rescheduling of tasks
Risk Management
Encountered Risk - Anticipated
Loss of a team member: Successfully managed through increased efforts
Delay receiving parts: Successfully managed through task rescheduling
Component failure: Ordered extra parts
Encountered Risk - Unanticipated
Complexity of technology: Marginally managed with additional research
Summary
The FM Transmitter project was meant to create a device that allowed the output of a personal music device to be utilized by a car or home stereo. While a fully functional device was not sucessfullly implemented, the groups technical knowledge was expanded and its project management skills refined.