Digital Notetaker

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Digital Notetaker

• Walter Jordan
• Tom Warsaw

Senior Design Project EECC 657
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Project Objectives

• Allow any standard whiteboard to be used as an
  electronic whiteboard
• Capture all whiteboard strokes digitally to PC
• Save as digital image to PC file

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System Diagram
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Sensor Strip
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Marker Sleeve
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Specifications

• Resolution within 5 mm of actual marker
  displacement
• Precision 2.5mm per pixel
• Accuracy judged at least 90 as readable as
  original writing (est. 50 samples/sec required)
• Range 1.25 x 1.25 meter whiteboard surface
• Time PC must display captured strokes within 1
  second of being written

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Analytical Component

• Marker position calculated using time difference
  observed between simultaneous IR and ultrasonic
  chirps
• Triangulated from two receiver locations

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Analytical Component (2)

• Will read marker position at gt 50Hz
• For accurate representation of motion
• 5mm accuracy for readability
• Time difference will need error less than
• 2.5mm precision
• The marker tip corresponds to 1 pixel on screen

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Recalibration

• Accounts for variance in speed of sound
• User prompted to place marker at predefined
  positions
• System calculates time/distance factor for
  current room temperature and pressure

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Division of Work

• Walter
• Sensor testing
• Circuit assembly
• Mounting board construction
• Tom
• Software Java application
• HC12 assembly program

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Work Progress

• Completed
• Acquisition of system components
• Software basic structure, GUI
• Ultrasonic sensor testing
• Outstanding
• Software serial port interface
• HC12 assembly program
• Infrared sensor testing
• Circuit assembly
• Mounting board construction
• Complete system assembly
• System testing

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Description of Completed Work

• Purchased
• Ultrasonic receivers (APC 40R-10A/W)
• Marker sleeve
• Software
• GUI
• Basic program structure

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GUI Design
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Java Software Class Structure
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Test Plan - Components

• Circuits
• The sensor receiver circuits be tested
  individually, using oscilloscope to check
  waveforms.
• They will then be mounted to whiteboard and
  tested to determine noise sources and maximum
  board size.
• M68HC12
• A terminal program will be used on a PC to view
  the serial port outputs of the HC12.
• PC software
• A test program will be used to generate data
  points for the program and observe the resulting
  marker strokes.

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Test Plan Total System

• Words and diagrams will be written on board
  digital image will be evaluated for readability
• A meter stick will be used to make tick marks 1.5
  cm apart the computer image will be evaluated to
  make sure marks resolve into separate points and
  occur at consistent distances.
• Recalibration will be checked with bad values to
  verify the negative impact

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Questions

• ?

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Performance

• Total power consumption
• Marker stylus 1.5V N-cell battery
• All other components work off wall outlets
• Potential safety problems
• Toxic marker fumes

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Performance System Cost

• Total system cost - 240.55
• 1 marker stylus - 50
• 2 APC 40R-10A/W sensors - 15
• 1 Optek OP954 sensor - 0.55
• M68HC12 microprocessor 150
• Serial connection cable - 15
• Resistors, Capacitors, Op-amps, Transistors,
  Diodes - 5
• Mounting board - 5