1. David Kim 396 Devin Galutira 396 Calvin Choy 396 Audio Feedback Handwriting Accessor

2. Problem Statement  Writing is easy for non blind people  Visual cues to aid in forming characters  Blind people have no or limited writing capability due to lack of sight  Signatures often done with a mark or x  If we can teach a blind person to write...  Then they can gain independence in the community, workplace & educational settings

3. Approach  Archimedes requests for a device to be used in research to train blind people to use Audio feedback as a substitute for visual feedback.  To develop one’s motor skills and muscle memory through Audio feedback & training.

4. Overview of Project  Handwriting Device characteristics  Device Equipped with Stylus  Sensor – Accelerometer  Microprocessor  Sound Synthesizer  Audio output

5. Initial Goals  Mobile  Device should be small and portable  Easy to set up and use in different places  User friendly  To produce a continuous audio feedback  Intuitive feedback to user  To experiment and discover the optimal set of sounds that is pleasant to the user.

6. Block Diagram Basic Stamp (Microcontroller) Speaker (Audio Output) Accelerometer In Stylus SoundGin Synthesizer - Accelerometer sends time/frequency data to Microcontroller. - Basic Stamp then sends Audio Data in Serial SoundGin Format to Synthesizer - Speaker outputs SoundGin’s audio - Stylus is moving within stencil.

7. Design Decisions  Accelerometer – Memsic 2125  Requested by Archimedes  Ready on Hand, easy to use  Small Package Size  Cheap  Basic STAMP  Requested by Archimedes  Ready on Hand  Versatile & Powerful with many capabilities  I2C, PWM, Serial for General I/O Pins

8. Design Decisions cont  Sound Synthesizer – SoundGin  Capable of producing smooth varying tones  Six Oscillators  Complex sound functions: modulation, mixing sounds  Wired Stylus vs Wireless  Simplicity for initial design  Accelerometer Position  Placed at the bottom of stylus for best sensitivity

9. Final Status  Prototype Complete  Plans for next version

10. Problem 1  Real time processing of accelerometer data  Divided processing work by adding a Sound Synthesizer  Basic Stamp – read & process accelerometer data  SoundGin – create corresponding sounds Solution 1

11. Problem 2  Converting Accelerometer data to Frequency Tones  SoundGin requires three 8 bit strings to the three registers: fine tune, mid tune, coarse -Accelerometer outputs digital PWM T1=time on, T2 = Period Stamp reads in digital PWM via Pulsin Command -T1(microseconds) is stored in a 16bit variable Solution 2

12. Solution 2 cont.  We set the fine tune to 0, since its changes are negligble  We split T1 into two 8bit strings.  Upper 8 bits reserved for controlling middle tones  Lower 8 bits reserved for controlling coarse tones  midy=y & %11111111 'get binary value to  coarsey=(y>>8) & %11111111 'set the oscillators  midx=x & %11111111 'frequency.  coarsex=(x>>8) & %11111111

13. Future Improvements -Reduce size of device to an elegant shaped stylus -Establish wireless communication (bluetooth, zigbee) between sound synthesizer to headset -Change method of reading in user movements, replace accelerometer w/optical mouse to record position -Incorporate panning to produce stereo sound

14. Questions?  Thank You

16. Code  ' {$STAMP BS2}  ' {$PBASIC 2.5}  '--[variables]-------------------  x VAR Word 'store x and y axis pulse width as 16 bit varibales  y VAR Word  midy VAR Word 'store 8 least significant bits of pulse width for adjusting  midx VAR Word 'mid frequency  coarsey VAR Word 'store 8 most significant bits of pulse width for coarse  coarsex VAR Word 'adjustment of frequency  '--[constants]-------------------  fine CON 0  esc CON 27  sec CON 3  osc1 CON 17  osc2 CON 33  soundgin CON 0  T9600 CON 84  OA1 CON 88  OA2 CON 89  Btn PIN 5  Initialize:  PAUSE 1000  GOSUB SGreset 'reset soundgin  SEROUT soundgin, T9600, [esc,OA1,200,esc,OA2,200]'turn on oscilator 

17.  Main:  IF Btn=1 THEN 'check for pen pressure  SEROUT soundgin, T9600,[esc,1,136,127]'set volumne  DEBUG "volume on",CR  DO WHILE Btn = 1'loop until button released  PULSIN 1,1,y 'get acceleration for y  PULSIN 3,1,x 'get acceleration for x  y=y-1000 'set harmonics  x=x-500  DEBUG "y=",DEC y  DEBUG " x=",DEC x,CR  midy=y & %11111111 'get binary value to  coarsey=(y>>8) & %11111111 'set the oscilators  midx=x & %11111111 'frequency.  coarsex=(x>>8) & %11111111  SEROUT soundgin, T9600,[esc,sec,osc1,0,midy,coarsey]'set frequency  SEROUT soundgin, T9600,[esc,sec,osc2,0,midx,coarsex]'for x and y  LOOP  DEBUG "volume off",CR  SEROUT soundgin, T9600,[esc,1,136,0]'turn off volume  'ELSE  'SEROUT soundgin, T9600,[esc,1,136,0]  'DEBUG "?"  ENDIF  GOTO main 'main loop

18.  SGreset:  SEROUT soundgin, T9600, [esc,esc,esc,esc,esc,esc,esc,esc]'clear oscilator settings  RETURN