Physical Design (hardware)

  • Mounting Device on cane vs. holding in hand
    • speaker phone vs. wired or wireless headset
    • directional issues
    • changes weight and balance of cane
    • beeps and vibration
    • access to buttons
    • occupies the user's hand
  • Optional compass
    • default mode that works without comapss use
    • benefits
      • solves issues for compass use (i.e. orientation, calibration, etc)
      • cheaper for user
      • no bluetooth necessary (more phones)
    • issues
      • calibration / orientation
      • error range
        • what is acceptable
        • account/filter oscillations and deviations
      • Where are we putting compass?
        • clip on for flexibility
        • clothes
        • belt
        • shoes
      • orientation
        • is it necessary to calibrate it so that it works in different orientations?
      • unexpected situations
        • i.e. throw in pocket
        • drop on floor
        • strong electromagnetic fields effecting readings
  • RFID
    • Standard protocol for RFID
      • look up current standards
      • identify uniquely that it’s for this navigation system
      • smart node at entrances
        • header
        • index
        • url

        • hash (security feature)
    • Security issues for RFID
      • verisign certificate?
        • We keep track of private keys for people who build maps (gatekeeper)
      • Encryption?
    • Tag collision
      • standard collision algorithms - reads one after the other so quickly that it seems simultaneous
      • interface issues (i.e. how/what to tell user)
    • Benefit for the RFID infrastructure to justify cost (selling point)
      • Cost argument (extensible software application)
        • blind navigation
        • general navigation/directory use
        • multimedia tours
      • Device argument (compared to other available devices)
        • cheapest such marker (i.e. compared to active things such as Bluetooth, IR)
        • range is good for indoor local navigation
        • contains enough data
        • predefined standard (see below)
  • Device requirements
    • Cell phones/PDA
      • Benefits of cell phones
        • Widely used by blind
        • Cheaper than PDA (sometimes)
        • Buttons come with
      • Drawbacks
        • More expensive for Bluetooth, wireless, rfid, etc
        • Private APIs
      • PDA
        • Open source APIs
        • More flexibility for expansion (i.e. CF or SDIO slots)
        • Built in Bluetooth, IR, wireless
        • Possible rfid cards available (though limited range)
        • Can possibly be more widely used since PDAs have standards in terms of attachments
        • Menu navigation issues (directional buttons)
    • Rfid reader
      • Communicates with cellphone/PDA through :
        • Bluetooth
          • Device needs it’s own power source
        • Unique cellphone plug
          • Limits phone types
    • Wireless connection
    • Provider for cell phones and wireless
    • Software & drivers
    • RFID infrastructure in buildings
      • passive RFID tags with about 10 ft range
      • read; write with certificate authorization

Software

  • User features
    • Ability to save maps (cached for future use, identified by RFID GUID)
    • global preferences for routes
      • handicap accessible
      • elevator or stairs
  • Creating map
    • hand-drawn at computer
    • automatically built by walking around environment
      • still need to label data at computer
      • requires more hardware (compass, odometry?)
    • graphing with directions

Interaction

Menus and prompts will be displayed on the screen and spoken using text-to-speech software. Input will be accepted via the number keypad buttons and voice recognition. User may speak the number of the menu item or the item itself.

In-depth look at cell phone

  • Benefits
    • people already have and use them
    • many now have built in wireless, Bluetooth
    • usually run java
    • RFID to predicted to come in the near future
    • Familiar/intuitive interface
    • Doesn’t attract undue attention
    • Already has common built in features we can use such as vibration and speaker phone
    • Voice recognition engine built into some
  • References
    • Businessweek: “Every major cell phone maker around the world is working on RFID-enabled phones in conjunction with banks and credit card companies.”
  • Drawbacks
    • different hardware interface (plug-in RFID)
    • limited by interface (i.e. limited buttons & no common shortcut buttons)
    • share function with communication (i.e. for phone calls)
  • Compared to PDA:
    • Benefits
      • built in wireless, bluetooth, infrared
      • extensible; CF card plug-ins being developed for RFID
      • runs java
      • built in mic and speakers
      • more support for developers
    • Drawbacks
      • people have them, but not as much as cellphones (especially the blind)
      • fewer buttons
      • large screen that blind can’t really make use of
  • Completely new design
    • Benefits
      • complete control of how we implement features

    • Drawbacks
      • price (cost of startup and product for user)
      • market penetration
  • INTERFACE
    • Common assumed cell phone interface available
    • Common Physical Inputs
      • 10 numbered buttons, # and * buttons
      • Directional arrows (up, down, and usually left right)
      • Select button
      • Power, dial, volume up/down shortcut buttons (soft keys)
    • Common Outputs
      • speaker phone
      • vibration
    • Additional Software & Hardware Requirements
      • Wireless (equipment & service)
      • RFID reader
      • Bluetooth ?
      • Compass ?
      • Voice recognition engine
      • Our navigational software
      • Text-to-speech (ideally built in to phone)
      • RFID network in environment