At this stage IMU accuracy is less important that functionality.  

In order of likely utilization:

  • Accel: ability to wake/interrupt processor when accel rises about some arbitrary threshold.
  • Ability to keep gyro, and mags turned off, but accel on until needed – initially all the time.
  • Quaternion output.
  • Accuracy vs range.  My guess is that we need +/- 3G and that accuracy is good enough.
  • Pace detection:  the ability to know that the person is walking, as opposed to just moving around is useful. Accel-only pace detectors are pretty poor generally.  If there are pace detectors that use the full IMU it would be good to know.
  • If we find some really excellent full IMU ded'reckoning code then that could be a significant factor.
  • I think I will try to use off-the-shelf drivers for as much as possible, and just use my own work to help understand how the drivers function, unless there are no drivers, and then I'll have to make them.  Using off-the-shelf means better reliability.

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