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
- header for
- index (unique ID or GUID)
- Electronic Product Code (EPC): GUID-like standard
- 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?
- verisign certificate?
- 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)
- Cost argument (extensible software application)
- Standard protocol for RFID
- 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)
- Benefits of cell phones
- Rfid reader
- Communicates with cellphone/PDA through :
- Bluetooth
- Device needs it’s own power source
- Unique cellphone plug
- Limits phone types
- Bluetooth
- Communicates with cellphone/PDA through :
- 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
- Cell phones/PDA
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
- Benefits
- Completely new design
- Benefits
- complete control of how we implement features
- Drawbacks
- price (cost of startup and product for user)
- market penetration
- Benefits
- 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