It’s Autumn, and that means the MPU-9250 is running outside of its ideal temperature zone. Every year, what flies beautifully during the summer deteriorates once the temperature falls firmly into the teens. That’s what’s happened yesterday with ambient @ 15°C. What was a rock solid hover two days ago has become unstable. Previous years, I’ve been able to move indoors with one of my smaller models, but that’s not an option this year. Hermione is simply too big to fly in the house and she needs to be this big to incorporate all the sensors and RPi 3B. Additionally, GPS is virtually inaccessible indoors.
To make things worse, all summer Hermione has been running an IMU which is outside of the spec accuracy range: it reads gravity as 0.88g – her accuracy should be 3% not 12%. She just about got away with it during the summer temperatures, but not now down in the teens.
Net? I’ve a new MPU-9250 on the way which will meet their spec; this should help somewhat, but at the same time, I think it’s fair to say that like the hedgehogs and squirrels round here, Hermione will be going into GPS hibernation, and only waking occassionally to test the sweep mapping of the indoors with very limited lateral flight movement.
As I result, I have updated the latest code onto GitHub.