Aside from Thanksgiving, I had a fun weekend.
I've been using a Feiyu-Tech gimbal on my Solo (because I wanted to see if I could get it to work), and wanted to be able to control the camera from my Solo's transmitter. The camera is a Xiaomi Yi, which I like. It's a great little camera that does a ton of cool things for an impressive price.
It turns out it wasn't hard to do at all. All I needed to do was get the camera onto the Solo's wifi network with a static IP address, and then detect when the camera button on the Solo's transmitter was clicked so I could send a command to the camera to start or stop video (or take a still picture).
Some Xiaomi-hacking geniuses have already figured how to set up the camera and what commands to send to it, and I built on that to control the camera.
It's not the "Solo with 3DR gimbal and GoPro" setup that most people are using, which is kind of the point. "Solo with Feiyu-Tech gimbal and Xiaomi Yi" is harder to pronounce, and harder to implement. But it works pretty well, and putting it together has been fun.
Here's some details about the camera setup, for whoever's interested:
Here's one: https://www.youtube.com/watch?v=_0oG2tTDunw
I've been fighting the mounting a bit. If I mount the gimbal normally, the Yi has to be oriented right-side-up so the HDMI cable can be plugged in. That puts the lens at the left side of the Solo. So any time I yaw right, I get a nice close-up of the left/front leg. To compensate, I fabricated a little mount that moves the camera forward about 1". That takes care of most of the "left leg" problem, but also messes with the CoG on the pitch axis. So I'm getting a lot of bounce in the picture. I'm currently waiting for the glue to dry on "Gimbal mount r2" (wood is still a great material for prototyping), and then I'll test it out. Hopefully that will cure the problem.
Ideally, I could offset the gimbal mount to the right about 1", which would bring the lens closer to the center line. But of course that would cause weird behavior in the gimbal. :-)
Great. most of the brushless gimbals (AlexMos, SToRM32) have their own attitude estimation so they work even just being held in your hand. The only ones that I know of that work in concert with the flight controller's IMU is the Solo gimbal and DJI gimbals. It's not really that difficult for us to send down the centrifugal (or is it centripetal?) corrections to the gimbal and it's on the to-do list. Once we do that the supported gimbals would all work a little better (probably) during high speed maneuvers.
Cool. I watched some footage from a Solo gimbal, and it's really smooth. I think I worked out what was causing the shaking. I had made a camera mount that offset the camera about 1 1/2" forward to help solve my "intimate portrait of Solo Leg when yawing right" issue. Bad idea! It's like mounting the camera on the end of a diving board. Putting it back in the normal position (and keeping my HDMI ribbon cable out of the prop wash) seems to make it much smoother.
Paul Riseborough (and Jon, Sid) did a huge amount of work on the Solo Gimbal to make it smooth like that. They did all kinds of analysis on the "resonances" of the gimbal (i.e. frequencies at which it vibrates) so that the controllers do the absolute best they can. I wasn't directly involved but watching from the sidelines I gained a new appreciation for their abilities in that area and how hard a gimbal is to get right.
From what I've seen in videos from that gimbal, they did a good job. $400 to a "gimbal newbie" like me seems kind of high, but the difference in the output between the two is obvious. At my rate, after messing with this $160 gimbal for as long as I have, I could have bought probably 4 Solo gimbals. :-)
A fair bit of the Solo's gimbal control is open source. It's in the AP_Mount_MAVLink library. We will probably eventually rename that to AP_Mount_Solo. There's a bit more that needs to be merged from the solo/ardupilot fork but it's on it's way. Anyway, the open source part is the complex part including the "SmallEKF". What's closed is the lower (and simpler) rate controllers that run on the gimbal itself.
Of course, I'm not saying it would be easy to get a gimbal working with the Solo libraries but I thought I'd point it out anyway. It would actually be easier to add the missing bits (i.e. the centrefugal corrections) into the SToRM32 or AlexMos drivers... of course neither of those two gimbals are open source either.
Good to know, thanks for the heads-up. I actually "discovered" the SToRM32 after I bought the Feiyu-Tech gimbal. I didn't realize there was someone making a Solo-compatible gimbal (which I understand the Storm is).
Could you elaborate on this SToRM32 Solo compatible gimbal someone is making? Do you have any links to that project?
I wonder then what the reason is for complaints about shaking in the Solo gimbal videos? Is it a mounting issue, location of cables etc.? I was very careful in mounting the cable to make sure no cables were touching the motor inside.
The videos I made does have some stuttering. Can that be caused by lighting conditions and camera settings? What about using a filter? There is so much I don't know about using a GP with the Solo gimbal, but think a lot of it may be in settings and whether a filter is used.
Where is a good place to read about getting nice smooth video from Solo? I've seen a number of them, but if it involves modding the Solo I'm not too keen on that.
It seems like stuttering/shaking can be caused by the slightest vibration, frames being skipped (if the camera has a low-grade SD card), low frame rate (looks like shaking, actually is just failure to capture movement smoothly), or a combination of the above. My Feiyu-Tech seems to be really smooth now as long as I'm in motion, but as soon as I stop to look at something and hold position, I see some shaking.
Yesterday I was experimenting with counterweights on the gimbal to balance it, and took it out for a test. I was flying about 30 mph about 1200' out and the cable that runs between the gimbal and its surrounding frame (which provides power, etc) popped out. The gimbal suddenly went dead. Talk about "shaking"... The gimbal went limp in the air and was flapping in the breeze. I thought for a second the Solo was about to crash because of all the tumbling and random trees and grass whirling around in the video. But no, just a crappy connector that doesn't lock into place. So I had to take it all apart and silicone the connector so it doesn't fall apart again.
Ah, looks like I was mistaken. I guess it's not specifically Solo-compatible. There's some support in it for APM though: http://copter.ardupilot.com/wiki/common-storm32-gimbal/
How is the video quality compared to the go pro hero4 black?