On a cold winter’s morning…


Both flights use identical code.  There are two tweaks compared to the previous videos:

  1. I’ve reduced the gyro rate PID P gain from 25 to 20 which has hugely increased the stability
  2. Zoe is using my refined algorithm for picking out the peaks in the macro-block frames – I think this is working better but there’s one further refinement I can make which should make it better yet.

I’d have liked to show Hermione doing the same, but for some reason she’s getting FIFO overflows.  My best guess is that her A+ overclocked to turbo (1GHz CPU) isn’t as fast as a Zero’s default setting of 1GHz – no idea why.  My first attempt on this has been improved scheduling by splitting the macro-block vectors processing into two phases:

  1. build up the dictionary of the set of macro-blocks
  2. processing the dictionary to identify the peaks.

Zoe does this in one fell swoop; Hermione schedules each independently, checking in between that the FIFO hasn’t filled up to a significant level, and if it has, deal with that first.  This isn’t quite working yet in passive test, even on Zoe, and I can’t find out why!  More anon.

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