Transcript Wireless Earphones with Remote Control

Wireless Earphones
Avionne Maurice & Jacqueline Suarez
Advisors: Prof. Hassib & Hedrick
March 5, 2005
OUTLINE
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Why Wireless Earphones?
Project Description
Similar Products
Original Project
Specifications
Actual Project
Specifications
Components
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Transmitters
Receivers
Block Diagram
Implementation
Results
References
Questions
WHY WIRELESS EARPHONES?
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Wanted to develop a
device which hasn’t been
explored thoroughly in
the wireless field
Increase our knowledge
in wireless and RF (radio
frequency) technology
Construct a device which
would be useful and fun
to use
PROJECT DESCRIPTION
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Wireless earphones are
lightweight ear-clip stereo
headphones made by
Maxell.
The earphones will be
used in conjunction with a
portable audio player.
Increased range of
listening.
SIMILAR PRODUCTS
GBA-SP Wireless Earphone
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Built-in FM Radio
Transmitter requires no
batteries.
Earphone receiver runs only on
2 AAA batteries.
The right earphone serves as
the control center.
The left earphone houses the
battery compartment.
SIMILAR PRODUCTS
Acoustic Research 900MHz Wireless Stereo Headphones
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Headphones work with audio or
video devices, like TVs, DVD
players, computers, etc.
Transmission range about 300
feet.
Rechargeable batteries
Transmitter is bulky
Headphone vs. Earphone
ORIGINAL PROJECT
SPECIFICATIONS
Suppression of unwanted signals at 45 dB
minimum
 FM modulation
 Battery Life: 8 hours minimum
 Receiver: Ear bud size
 Transmission Range: 300 ft minimum
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ACTUAL PROJECT
SPECIFICATIONS
Suppression of unwanted signals at 40 dB
 FM modulation
 Battery Life of Receiver: 25 hours
 Battery Life of Transmitter: 25 hours
 Receiver: Ear-clip size
 Transmission Range: 200 ft
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COMPONENTS
RF transmitter
 RF receiver
 Battery
 Earphones
 Antenna
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OLD TRANSMITTERS
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RTF3-433 FM RF Transmitter Module
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Quasi AM/FM RF Transmitter Module
TXM-xxx-A/F FM RF Transmitter Module
Originally we had 3
different transmitters
from which to choose.
Each transmitter had a
wide supply voltage, long
transmission range, and
average in cost.
OLD RECEIVERS
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Initially there were two receivers to match the three
transmitters.
Fairly expensive – about $50.00
Dimensions weren’t very small
SILRX-xxx-A/F FM SuperHeterodyne Receiver Module
QMR1-433 Quasi AM/FM Receiver Module
NEW TRANSMITTER
FMST-100 STEREO TRANSMITTER
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Tunable from 76-108MHz
Compatible with any audio
device, like a CD player or
tape deck
Uses a BA1404 IC chip
Transmission range is 200
feet
With 9 V battery, has a
battery life of 25 hours
Price: $29.95
NEW
RECEIVER
TDA7000 FM Radio Receiver
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Supply voltage range: 2.7 to 10 V
Supply current: typical 8 mA
Frequency range: 1.5 to 110 MHz
Sensitivity: 1.5 mV
With 3 V battery, has a battery life of 25 hours
Price: $15.95
BLOCK DIAGRAM IMPLEMENTATION
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A CD player was used for the input signal.
The audio signal was then received by the FMST-100 stereo
transmitter.
Within the FMST-100 stereo transmitter the signal is amplified and
modulated by the BA1404 IC chip.
The signal is then transmitted and received using the antennas.
Inside the TDA7000 FM Radio Receiver chip, the signal is
demodulated and amplified so it can be heard with the wireless
earphones.
RESULTS
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Transmitter is functional
Debugging completed for transmitter
In the process of debugging receiver
Mount transmitter in box
 Increase stability of transmitter
 Design an antenna system
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REFRENCES
www.bestbuy.com
 www.jameco.com
 http://www.semiconductors.philips.com
 http://www.users.bigpond.com/cool386/tda
7000/tda7000.html
 http://www.microbattery.com/Toshiba%20
Webpages/lithium%20coin%20new.htm
 http://www.semiconductors.philips.com/pip
/TDA7000.html
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SPECIAL THANKS TO
Gene Davison
Professor James Hedrick
Professor Ekram Hassib
QUESTIONS?