Inertial navigation peripheral/91108


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Initial Design/Project Goals

Want Has

  • real world coordinate plane
    • "no mindfucks"
  • attach to laptop
    • conducive to running, doesn't fall off and break
  • aesthetically pleasing
  • unobtrusive


  • collaborative paint tool
    • less features, more people
  • Tron
  • Pong (small scale demo app)
  • tennis? (kind of Wiimote like)
  • tutorial app

Making things work

USB HID device

  • don't get full access to variables
  • three axes of acceleration
  • three axes of gyro


  • delta x, y, z
    • z is an optional channel
  • need 18-series pic for support
  • pic math is bad! --jay
  • would prefer to make XO do number crunching
  • This pic math is doable -- numerical integration, trig by lookup table
  • rich communication vs laptop
    • smarter
    • Want to know...
      • (a) Where I am
      • (b) What my bearing is
  • Greg says we should write a library for this.

Proposed interaction storyboard

  1. Obtain XO and peripheral
  2. Connect peripheral to XO
  3. Launch paint
  4. put XO in tablet mode
  5. (your friends do the same!)
  6. shows dot where you are, where other folk are (similar to GPS dot) --- *)))) <-- dot plus waves
    • ping button -- where am I? (or a subtle constant ping)
  7. run: "dot should ping in the direction you're running" (or place you've been. Will decide later)
    • "pheromone trail thing"
  8. When done... you've painted American Gothic! :)

moar design considerations

  • pen up/pen down
  • toggle vs momentary
  • four button control scheme
    • up - pen up
    • left - LOL
    • right - rotate
    • down - pen down
  • super simple broad interaction - plug in and RUN

Good practices

  • UOCD
    • Make paper thingies to show people
    • physical thing to show


  • magnetically
    • "null field magnetometer"

(compass method)

    • likely to be slow (Greg)

To Do

  • experiments
    • tolerance of hall effect sensors
    • response time of compass method
    • play with ADC and an accelerometer
    • Synchronization of multiperson activities
      • host system
      • how do we utilize mesh?
        • Which person at 1cc knows about mesh?
        • API

Personal Goals

  • how an accelerometer works
  • Precision
    • drift/location error should be less than 10% (if you move 10 meters, hit 9 or 11)
    • Calibration will be necessary
    • OPTIMISTIC goal
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