GSoC 2008

Andy Green andy at
Tue Mar 25 09:29:59 CET 2008

Hash: SHA1

Somebody in the thread at some point said:
> Niluge KiWi wrote:
>> With the two accelerometers in the FreeRunner, I think we can recognise
>> lots of gestures, not only simple ones like a "click" (which is already
>> recognised by the accelerometers used in the FreeRunner). The main
>> difficulty is probably to extract the useful data from the gestures
>> noise : calibration may take time. The goal is to have an almost
>> pre-calibrated library (an idea from the wish-list in the Wiki is to
>> allow the user to record its own gestures, but I think it's not easy to
>> do it simple for the end-user).
> Good idea, but consider to store calibration data separately. This will
> made the library more general. You want reuse it in other devices.
> So the "recorded" gestures.

There's another constraint on this, in the future a very weak 16-bit MPU
may have the duty to interpret the sensor data into gestures.  Whatever
we do for Freerunner and get it right, it would be perfect to port it to
this proposed future "sensor management" MPU.

It means that a perfect solution is predicated around

 - 16 bit integer arithmetic -- ha "no float" is too easy
 - per-sample short processing rather than large batching
 - multiply is expensive (but hey shifting is cheap :-) )

The raw accelerometer data is predicated around byte data for X Y Z per
sample per motion sensor.

- -Andy
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