Bluetooth Auto-Silencer
Final Presentation
Senior Design I
Team Members
Barbara Fountain
Delos McManus
-EE
- Power Controls
and embedded
layout
-EE
-Antenna
control/feedback and
embedded layout
Mike Brokhoff
Brantley Brokaw
-CPE
- Programming
mobile device
-CPE
- Programming
microprocessor
Faculty Advisor
Dr. Pan Li
Assistant Professor
• Ph.D., Electrical and Computer Engineering, University of
Florida, 2009
• B. Eng., Electrical Engineering, Huazhong University of
Science and Technology, Wuhan, China, 2005
Academic/Research and Fields of Interest:Wireless
Networking
• Wireless Communication
• Mobile Computing
• Computer Networks
Overview
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Problem
Solution
System Overview
Constraints
Hardware Testing
o Power Supply
o Microcontroller
Software Testing
o Android Application
Complete System Testing
Remaining Tasks/Timeline
Questions
Problem
As cell phones become more common in
everyday life, the need for cell phone
etiquette has become even more apparent
in certain areas of public life.
Incoming
Call
Solution
Use Bluetooth technology to develop a
hardware and software combination that
will automatically silence cellphones.
Incoming
Call
System Overview
Technical Constraints
Name
Description
Power Supply
Must use 120 VAC.
Software
Must operate on the Android version 2.2 as a test
base. Further expansions of mobile operating
platforms are planned.
Frequency Band
Software Response
Timing
Must transmit in a bandwidth between 2.4 and 2.48
GHz in order to comply with the Bluetooth
standard.
Cannot have a latency longer than 3 seconds.
The transmitter must have a line-of-sight range of
Transmission Distance
100 feet without obstructions.
Practical Constraints
• Economic
• Political
Economic Constraint
The transmitter must cost no more
than $150, and application software
will be free to all mobile device users.
Component
Price
Bluetooth Modem - BlueSMiRF RPSMA
$64.95
2.4GHz Duck Antenna RP-SMA Large
$9.95
PIC24HJ32GP202 Microcontroller
$3.50
PCB Fabrication
Miscellaneous Circuit Elements Total
Total
$35.00
$4.58
$117.98
Political Constraint
The BAS must not violate the
Communications Act of 1934.
[2]
Hardware Testing
• Power Supply
• Microcontroller
Power Supply
• 120 VAC is rectified to 6.0 VDC.
• 6.0 VDC is bucked down to 3.3 VDC.
• The voltage for each device was measured
across its coupling capacitor, as shown below.
Power Supply
• All measure values are within tolerance of both
the PIC24HJ32GP202 and the Bluetooth module.
Expected Value Measured
(Volts)
Value
(Volts)
Percent Error
(%)
Rectifier
6.000
6.182
3.033
Voltage
Regulator
3.300
3.297
-0.009
Microcontroller
• The microcontroller communicates with the
Bluetooth Module.
• The communication was observed via a USB
Logic Analyzer.
USB Logic Analyzer Test
Software Testing
• Android Application
FSM Diagram
Android Application
• Emulator
o Creating Graphical User Interface
o Control Ringer State
o System Timer
• Mobile Device Deployment
o Turn On/Off Bluetooth module
o Control discovery
o Read devices being discovered
o Response Timing
Graphical User Interface
Control Ringer and Timer
Bluetooth Control and
Discovery Reads
Worst case Latency
Latency Testing
Time Delay (seconds)
7.0
6.0
Time Delay (s)
5.0
4.0
3.0
2.0
1.0
0.0
1
2
3
4
5
6
7
Average Delay
Expected Delay
Percent Error
8
9
10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30
Sample Number
2.3 seconds
3.0 seconds
-24.44%
Complete System Test
http://www.youtube.com/watch?v=FSbmphjOzj4
Technical Constraints Overview
Name
Description
Power Supply
Must use 120 VAC.
Software
Must operate on the Android version 2.2
as a test base. Further expansions of
mobile operating platforms are planned.
Frequency Band
Must transmit in a bandwidth between
2.4 and 2.48 GHz in order to comply with
the Bluetooth standard.
Software Response Cannot have a latency longer than 3
Timing
seconds.
Transmission
Distance
The transmitter must have a line-of-sight
range of 100 feet without obstructions.
Complete
Distance Testing
Problem: Transmission Distance
is too large for small rooms
Solution: Switch added to vary
transmission power
Timeline
August
Research
Hardware
Design
Prototyping
Testing
September
October
November
Senior Design II Goals
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Finish Implementing Android GUI
PCB Design
Deploy Application to Android Market
Expand application to another OS
References
[1] Wikipedia, “Mobile phone,” Wikipedia. [Online]. Available: http://en.wikipedia.org/wiki/Mobile_phone.
[Accessed Aug. 31, 2010].
[2] Federal Communications Commission, “Sale or Use of Transmitters Designed to Prevent, Jam or Interfere with
Cell Phone Communications is Prohibited in the United States,” Federal Communications Commission, July 27,2005.
[Online]. Available: http://www.fcc.gov/eb/Public_Notices/DA-05-1776A1.html. [Accessed: Aug. 31, 2010].
Questions?