The 1st gimbal.
Results with the 1st gimbal:
The 1st gimbal was a beast to carry around, requiring an 11.1V 5Ah battery to go 2 hours. It was limited by the fabrication tools.
The 2nd gimbal:
The Feiyu Mini 3D was a miracle of brushless gimbals in terms of its small size & price, but it didn't really work because of nagging firmware problems. This is alternative firmware to get the essential functionality, but not a complete feature set. Once installed, the original firmware will be completely lost. It's more for documenting how a brushless gimbal works.
After their 1st appearance, brushless gimbals quickly faded from miracles to a part of every quad copter as forgettable as landing gear. Open source firmware development stopped. Future generations were happy using them without knowing how they worked.
Getting good results is a tricky problem involving feedback control & multivariable calculus. Sadly, anyone wanting to build one or fix one would be hard pressed to find examples.
Convenient carrying case.
Results with the Feiyu:
It goes 2 hours on a 2Ah 7.4V battery. This is still not a complete implementation. It doesn't handle roll/pitch offsets properly & there's still quite a shake which was subdued by sampling every 20 frames.
Download source code without support
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