The quadcopter I wrote about in Getting in to Quadcopters met an untimely demise recently. In that post I wrote aboout how I flew it into a tree. That caused one of the motor mounts to break. Looking more closely at the design, I realized some of the comments I’d read online were accurate. There’s a weak point in the frame, right where the outermost part of each arm has the motor mounted on it. If that gets hit too hard it’ll just snap.
And so it goes.
Luckily, I was able to find a repalcement frame a couple weeks ago. I bought the now discontinued Micro Quad Kit from Polakium Engineering. It was roughly $20 for a new set of arms, as well as an upper and lower plate. So I spent several hours last Saturday taking the old one apart, gluing the new parts together, and mounting the motors and componenets. All in all it was a pretty easy seutp to work with.
Full pictures of the process are in my Micro Quad Replacement album on Picasa.
I also have to highly recommend his on-line book The Beginner’s Guide to Multicopters which contains a wealth of good information, most of which I learned the hard way over the last several months. If I had discovered this first, I’d have been much farther along.
The whole process took a bit longer than I expected, but that’s partly because I was being really careful to preserve and salvage as much of the old setup as possible. Not bad for a 3D printed replacememnt.
Once it was reasonably secure, I mounted the KK2 flight contols board on it and hooked everything up.
And what I should have done next was to fly it and just have some fun. But I decided I’d take the opportunity to upgrade the firmware on the KK2. It was still running the relatively old 1.2 and 1.5 was supposedly much improved–especially in the auto-level department. So I grabbed a copy of LazyZero’s KKMulticopter Flashtool and upgraded by board to 1.5.
The process worked as advertised, thanks to the USBasp AVR Programming Device for AMTEL processors that I picked up from HobbyKing.
After flashing it, I went thru the menu again to check the settings. I made sure that auto-level was back on Channel 5, the motor layout matched, reciever test passed, etc. And then I did a few low-power tests to make sure the motors all spun in the right direction. Things seemd to work well.
So I put it on the floor and intended to apply just enough power to get it off the ground. When I did it seemed very unstable–so much so that it flipped over and I cut the power. Then I double-checked things again and spent some time trying to see what might have been wrong. Everything checked out well.
I had some problems with instability on the original frame and learned that the best thing to do was apply a bit of extra power to it would “leap” into the air and then I could fine-tune the control. So I decided to use that appraoch with this frame too.
Bad idea. Very bad.
The copter flipped over quickly and self-destructed. One prop broke, two motors ripped off from the frame, and things kind of fell appart. Clearly something was wrong. Either I messed up in re-assembling it all. Or, as I suspect, something in the change from version 1.2 to 1.5 of the KK2 firmware really changed and I completely missed it.
The bottom line is that I think I need to retire this Micro Quad and work on a something a bit larger and more stable. If I’m lucky, Santa will bring me a DJI 450 kit to build. :-)
Here’s an overview of a DJI 450 with a GoPro on it:
And here’s a video of it flying.
Note that he also used the KK2 board on his. I’d like to do the same and then upgrade to using APM 2.5+ at some point so that I can program semi-autonomous flight missions.
He has a ton of useful RC flying videos that I’ve used for inspiration and pointers to more information and gear that I can use at some point. Highly recommended.
Next up, the first (long-overdue) flight of my R/C plane (weather permitting)…