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Mar 18, 2016, 11:19 PM
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The brushless gimbal plan


Washington DC Timelapse run (7 min 33 sec)


After making that, a better stabilization system became a lot more desirable. So basically, the brushless gimbal made 3 years ago ended up too big & cumbersome to be useful for most running videos or traveling. There's no way without the power of Chinese manufacturing to miniaturize it. Either that or the cost would be more than a commercial version.

In the future, 360 cams will replace all brushless gimbals, but there is currently no incentive for anyone to make a 360 cam work like a brushless gimbal when it's cheaper to borrow money. There might be a way to hack it. Years ago, there was an attempt to use a phone's internal IMU to stabilize the video from its own camera. The problem was they had to use an off the shelf phone & only the software APIs included. The focal length was too long to give enough overscanning area. The IMU wasn't fast enough to track fast movements. It only worked if the API gave time stamps which could synchronize the video with the IMU data.

The new idea would be capturing IMU data externally from the camera & synchronizing it by reading the VSYNC pulses from the sensor. New cameras may not have an exposed VSYNC signal. It's not likely the clocks would stay synchronized tightly enough to pull it off.

The raw IMU deltas would be recorded on the microcontroller's flash. They would generate offsets for Cinelerra's motion tracker. They would have to be exactly synchronized with the shutter.

The problem is a brushless gimbal doesn't apply just roll, pitch, yaw angles. It applies the raw gyro deltas to the servo motion. The gyro deltas have to be recorded at high speed. 1.5MB of internal flash would last 5 minutes. This could be upgraded to an SD card, once the system was proven. This would be the most compact system but have the risk of losing money on a new camera with no VSYNC signal.

The lens correction to make seemless motion isn't implemented & rolling shutter artifacts would be unsolvable.

Despite the problems, a risky fisheye cam + microcontroller hack would be around $100 & the most compact solution, but would have rolling shutter artifacts.

A Feiyu G3 with the obsolete gopro is $230 but guaranteed to work, with no rolling shutter artifacts. The Feiyu G4 is $250 just to support a gopro 4. The trick with the Feiyu is they don't allow motion control when the axes are locked for a timelapse movie. This requires the $300 G4S, which includes a joystick. The joystick adds $70 to the base price, proof Chinese are bastards.

A Bebop drone just for the camera is $500, well out of reach.

The winner is the Feiyu mini 3D for $140, fashioning a handle & control board from scratch to control it by PWM, powering it from a lipo. It seems identical to the Feiyu G4S without the handle, so simple to upgrade to the full functionality of the G4S without paying $160, people outside China must be hopelessly stupid to pay for a G4S.

None of these solutions provides an LCD viewfinder, but we've come to an age where the human population has evolved to not need viewfinders.
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