Transcript Slide 1 - Senior Design

FM Transmitter
Dec06-01
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
Project Overview
Objective:
Design a portable short range FM transmitter for
use with MP3 players or satellite radios
Presentation Outline
Introduction
Project Overview
 Problem Statement
 Assumptions, Limitations, Requirements
Project Activities
 Approach and Design
 Implementation and Testing
Resources and Schedule
Conclusion
Definitions
FCC:
FM:
LCD:
MP3 player:
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)
Satellite radio:
subscription radio signal sent via satellite, (i.e. XM radio,
Sirius radio)
Transmission frequency:
the frequency at which the device is transmitting the FM
modulated signal to the FM radio.
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
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: ≤0.1kW
 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.
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.
Present Accomplishments
 Problem Defined
 Research Completed
 Technologies Selected
 Design Completed
 Design prototyped
 Prototype testing
 Project documented
Key
Completed
In Progress
Approaches Considered
Logic Approach
The logic for the transmitter could be implemented either with a microcontroller
and software or with dedicated hardware logic.
Microcontroller/Software
Cost ≈$7.00
Ease of Requires software to be written,
Implementation compiled and loaded
Weight/Size One large IC
Expandability & Requires software to be
Modifiability changed and recompiled
Hardware Logic
Advantage
≈$7.00
none
Requires detailed
design and intricate
implementation with
more components
Microcontroller
Several small
components
none
Requires full
redesign of entire
circuit
Microcontroller
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: ≤0.1kW
 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
Design Activities
Signal Processor
 Rohm BH1415F
 SOP22
 Phase Locked Loop
 Stereo Capability
 Built in pilot tone
 Serial communication
with microcontroller
Design Activities
Overall Schematic
Implementation Activities
Component Communication
 Serial Connection from microcontroller to signal processor
Implementation 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
Breadboard Implementation
 Preliminary Implementation
 Testing for functionality
 Necessary modifications performed
Schmartboard
 Surface mount components
 Allows for easy prototyping
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
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
Resources
Personnel Efforts
 4 Team members first semester
 3 Team members second semester
 Jacob Sloat studying abroad
Personnel Ef f orts
235
227
232
250
200
137
150
100
50
0
Grant
Jacob
Luke
Tony
Resources
Project Finances
Parts
Financial Requirements
$35
Printing &
Binding
$15
Poster
$100
`
$23
$12
Case
PCB
Resources
Project Schedule
Problem Definition
Design Research
Finalization of Design
Prototype Implementation
Prototype Testing
Final Product Implementation
Final Product Testing
Final Documentation
J
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A
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J
J
A
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Conclusion
Project Evaluation
 Many objectives completed
 Several tasks in progress
 Expected full completion by
December
 Problem Defined
 Research Completed
 Technologies Selected
 Design Completed
 Design prototyped
 Prototype testing
 Project documented
Key
Completed
In Progress
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
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!
Conclusion
Risk Management - Anticipated
 Loss of team member
 Delays in obtaining parts
 Component failure
Risk Management - Unanticipated
 Complexity of technology
 External commitments/responsibilities
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.