P08009 Audible Memo Board Phase II Friday, February 22, 2008 P08009: Audible Memo Board Phase II Sponsor: Dr. Hopkins Advisor: Professor Slack Jon GosligaElectrical Engineering Loic HureauElectrical Engineering Jim VargheseElectrical Engineering Alex GorevskiComputer Engineering

Overview Project Description Ergonomics Software & Hardware Design Technical Issues MSD II Timeline Test Plan & Results Future Considerations Conclusion Questions / Comments 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

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 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 Friday, February 22, 2008 P08009: Audible Memo Board Phase II

Design Concept Button Functions Friday, February 22, 2008 P08009: Audible Memo Board Phase II Erase Playback Record Change Month Next/Previous Message Calendar/Memo Mode Change

Software Logic Friday, February 22, 2008

Electrical Sub-system 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 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 Friday, February 22, 2008 P08009: Audible Memo Board Phase II

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 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 Friday, February 22, 2008 P08009: Audible Memo Board Phase II

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 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 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

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 V Obtain Maximum Signal Without Clipping Power Supply Testing Anti-Aliasing / Smoothing Filters Major Topics Addressed Device Functionality Key Debug Code Clock Chip Debug Code Idle State Debug Code ADC Sampling Frequency ADC Input Voltage Levels V Obtain Maximum Signal Without Clipping Power Supply Testing Anti-Aliasing / Smoothing Filters Friday, February 22, 2008 P08009: Audible Memo Board Phase II

Test Results

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 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 Friday, February 22, 2008 P08009: Audible Memo Board Phase II

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 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 Friday, February 22, 2008 P08009: Audible Memo Board Phase II

Thank you for attending. Questions? Monday, October 22, 2007 P08009: Audible Memo Board Phase II