Transcript Final Presentation (2-24-08)

P08009: Audible Memo Board Phase II
Friday, February 22, 2008
P08009
Audible Memo Board
Phase II
Sponsor: Dr. Hopkins
Advisor: Professor Slack
Jon Gosliga
Electrical Engineering
Loic Hureau
Electrical Engineering
Jim Varghese
Electrical Engineering
Alex Gorevski
Computer Engineering
P08009: Audible Memo Board Phase II
Overview
•Project Description
•Ergonomics
•Software & Hardware Design
•Technical Issues
•MSD II Timeline
•Test Plan & Results
•Future Considerations
•Conclusion
•Questions / Comments
Friday, February 22, 2008
P08009: Audible Memo Board Phase II
Friday, February 22, 2008
Project Description
•Device is able to Record/Playback audio messages.
•Features implemented to aid a person without the use of
vision and limited feeling in the fingers.
–Velcro on every Wednesday to distinguish days of the week
–Verification logic in case of accidental button presses
–Audible instructions that are interruptible
•Key customer needs / engineering specs:
–Reduce steps in recording and playing back messages
–Layout should resemble a traditional calendar
–Time and data are retained when the power is off
•NAND Flash memory incorporated to retain audio data
•Clock Chip with an internal battery on power-down
–The user can record, delete, and playback messages & the
messages are easy to find
P08009: Audible Memo Board Phase II
Friday, February 22, 2008
Design Concept
Button Functions
Change Month
Record
Next/Previous
Message
Playback
Erase
Mode
Change
Calendar/Memo
Friday, February 22, 2008
Software Logic
Friday, February 22, 2008
Electrical Sub-system
P08009: Audible Memo Board Phase II
Friday, February 22, 2008
Major Technical issues
How do we keep the memory from running out?
• Automatic checking of old appointments (idle state of 5 minutes)
• Check only takes 0.5 seconds (1200 locations)
• Maximum downtime is 4 seconds
• Dynamic memory allocation and deletion (no memory leaks)
Clock Chip Data Acquisition
• Evaluation board is able to run at 5.5 Volts (non-extended
operation)
• Data only accessed when necessary
• Data lines turned off instantly after the data access (5 uSeconds)
DC Charge Pump
• -12 Volt supply did not generate enough current
• Part was replaced with a better component with better specs
P08009: Audible Memo Board Phase II
Friday, February 22, 2008
Major Technical issues
Speaker Fidelity
• Additional stereo jack equipped to box
• Option to plug in standalone speaker system
• Noise was reduced with additional high & low pass filters
Battery Life on the Microphone
• Power supplied directly to microphone from perf. board
• Batteries are still used for microphone stability
Input Signal
• Increase gain in the amplifiers to send a stronger signal to the ADC
Physical Connections to the Evaluation Board
• 30 Gauge wire & wire-wrapping was too fragile
• 26 Gauge wire & solder points found to be sufficient
MSD II Schedule
• Week1:
•
•
Clock Chip Testing
Update Schematics
• Week 2:
•
•
•
Finish testing the clock chip
Write key-debug code
Perf Board Layout
• Week 3:
•
•
Finalize Device Code
Verify the power conditioning
circuit
• Week 4:
•
•
Make Calendar Mode functional
Build Circuit on new Perf Board
• Week 5:
•
•
Make Memo Mode functional
Debug new Perf Board
• Week 6:
•
•
•
•
Debug Code
Re-solder all connection on back
of board
Finalize all connections
Debug Board
• Week 7:
•
•
•
Verification Testing
Debug Board
Secure wires in box
• Week 8:
•
•
Debug
Functional and performance
review.
• Week 9:
•
•
Debug Board and Software
Poster/Conference Paper
• Week 10:
•
•
•
Debug Board and Software
Conference Paper
Final Schematic
P08009: Audible Memo Board Phase II
Test Plan
Major Topics Addressed
•Device Functionality
• Key Debug Code
• Clock Chip Debug Code
• Idle State Debug Code
•ADC Sampling Frequency
•ADC Input Voltage Levels
• 0 - 3.3 V
• Obtain Maximum Signal Without Clipping
•Power Supply Testing
•Anti-Aliasing / Smoothing Filters
Friday, February 22, 2008
Test Results
Frequency Response of Filter
2.50E+01
2.00E+01
Voltage (V)
1.50E+01
Series1
1.00E+01
5.00E+00
0.00E+00
0
500
1000
1500
2000
2500
Frequency (Hz)
3000
3500
4000
4500
P08009: Audible Memo Board Phase II
Friday, February 22, 2008
Future Considerations
Possible Next Steps
• PCB Board can be designed with the up-to-date
schematic
• Evaluation board could be avoided, money saved
• Clock chip to be replaced with one that is not obsolete
• Software logic would use actually interrupt routines (for
readability)
• Rather than simulated interrupts through polling
• Design a power amp to better drive the internal speaker
• Increase memory size (to allow for more appointments
with little overhead)
• Better quality microphone to compensate for voices at
far distances
• Smaller box design to accompany PCB design
P08009: Audible Memo Board Phase II
Friday, February 22, 2008
Conclusion
Many design changes would be made in the
future
• Many unforeseen problems during design
• These problems ate up more time than was
expected
•Tradeoffs for functionality vs. time constraints
were made
• Power Button & External Speaker
•Project was an overall success
P08009: Audible Memo Board Phase II
Thank you for
attending.
Questions?
Monday, October 22, 2007