GoPro Karma Stabilizer Teardown

I crashed my drone. Really bad. It literally snapped the Gimbal arm in half. So I had to order another one because I was stupid and I didn't get the extended warranty because I didn't think I'd ever fly that close to low hanging trees. Sinking this much money into a GoPro drone is worth it, though, because I've had nothing but good experiences with their products (although they're not great at figuring out what to do when upside down on the pavement. But, like my dad says, there are two kinds of remote pilots: those who have crashed and those who are going to crash. I guess technically I'm in both categories now. The point is is that I have a broken gimbal and I can take it apart now because there is a less than 0% chance I can fix it and I already have another one.

Here's the interesting thing, the part that broke wasn't plastic. It was metal. The crash was hard and bad enough that it sheared the metal at the arm. It wasn't from very high up, maybe only five feet high, but gosh it hit hard. One thing I learned through this teardown, however, was that this is, in fact, soft metal.

Whatever, let's take it apart!

First, let's take apart the half that connects to the camera harness. This requires a variety of very small Torx screws (no surprise there), so get out your small star heads and get unscrewing. I unscrewed all of it at once to get the metal and plastic off.

There's a small PCB inside of the arm that has a TI Microcontroller in it. This isn't the exact one in the arm, but it's close. Adjacent to this board, there's a DRV8313 Three Phase Brushless Motor Driver which gives us a very clear indication about the kinds of motors these are. The fact that each motor has three wires was another big hint.

There is also a small chip on the axis of each motor that I can only assume are accelerometers, gyroscopes, or both. I can't find the documentation on them but they're the right size, shape, and package to be an accelerometer. It would certainly make sense to have an accelerometer at the center point of the motors so it can report back an accurate reading of its axis with respect to gravity (instead of encoders which wouldn't really work in this case).

Another small PCB was located where the USB-C connector for the camera is. This is an Invensense MPU-6000 Six Axis Integrated Motion Processor (three axes are acceleration, the other three are the gyroscope). This chip is perpendicular to the normal angle of the camera view, so it's probably the most important sensing chip on the board. This, as well as the USB-C connector, are the main reasons why we have this horrible snaking ribbon cable going throughout the arm. It also delivers power to the motors and boards as well.

That about does it for that half of the gimbal. Now let's deconstruct the other part - the part that plugs into the drone/grip. Again, just remove all of the plastic and screws to see what we're left with. The arm was exactly the same with the same PCB, same microcontroller, etc. It's starting to become clear why this is so expensive.

There's not much on these boards, either. You have another motor driver and a USB-C port. But the main processor is on this board. And, although the package is much bigger, it's probably just a bigger microcontroller from the same or a similar line to the other ones.

So is that it then? Yeah, pretty much. It turns out that a gimbal isn't too complicated, you just have to have really fast microcontrollers to process very accurate positioning and accelerometer data in order to drive fairly accurate and smooth motors. Maybe someday I'll try to make my own gimbal, but definitely out of these parts. Maybe some other time I'll try to drive these motors now that I know they're just three phase brushless motors. They seem super smooth (they have to be, I'm not sure how they got away with only three phases) so maybe I can make them do something. But, despite the lack of a wide variety of components, I have gained a better appreciation for why this gimbal, and others, are so expensive. Not only are the parts of very high quality, but the engineering that goes into making this work the way it's supposed to is impressive as well.