Someone asked about the magneto (or lack of it) in my previous post, so here's the reason it was absent…


I could've just soldered the cable on, but figured i might want to use it for other Arduino projects occasionally. This makes it a much simpler task:


Word of advice: don't push the pins all the way down when soldering, or they'll stick out too much from the bottom of the magneto PCB (it's pretty thin) and you won't be able to mount it flat on the carrier plate. Oh, and G on the plug stands for GND.

Anyways, let's move on. Ever noticed how the ArduCopter frame's GPS carrier plate and dome center come with two M3 screws, but *four* M3 nuts? Ever wondered why?


Mmmm. Bendy. Here it is with four nuts:


Much better.

As i was about to put the dome and legs on my ArduCopter, i found another thing off. Can anyone spot what's wrong with this picture?


That's right, i can't plug the USB in the IMU. The standoff is in the way. I'm an idiot and have to unscrew everything again. Yay… Here's the wrong way to mount the APM/IMU sandwich (smack dab in the middle of the carrier plate on both axes):


… and here's the right way (moved one hole towards the front):


Oh, by the by, do not tighten the nuts on the upper carrier board. Leave them slightly loose. Why? So you can do this:


… when you want to take the upper board off (to access the APM/IMU). Unscrewing the standoffs is much easier than unscrewing the nuts, plus, it doesn't require any tools.

Speaking of tightening, careful with those plastic screws. They crack like eggshell. The moment it goes "crick" the first time, it's tight enough. Here's how, where and why they crack:



As you'd have probably guessed by now, i'm a heat-shrink tubing junkie. As far as i'm concerned, it's the best and most convenient thing since sliced bread. It makes mess not look like mess, it protects and isolates, it marks and identifies… I can never have too much of it.

Or can i?

Turns out i can. Because it also makes cables rigid. Which leads me to the first no-no of arducopter frame-building. This:


… seemed like a good idea at the time (bright yellow makes the battery cable easy to spot when i'm plugging/unplugging it in a hurry), but makes my life miserable every time i try to plug the battery in, because the heat-shrink tubing keeps trying to straighten the cable out when i want it to curve underneath the ArduCopter main plate. Re-heating it while keeping the cable curved helped somewhat, but in retrospect, it could've done without it.

On the other hand, here:


… the rigidness turned out to be useful, because it keeps the PDB<->RX connectors neatly grouped and packed together so i can unplug/plug them into the receiver all at once.

Finally, motor mount LED covers. I didn't get any with my ArduCopter frame kit. Because, apparently, they don't come with version 1.0 (despite there being a hole in the motormounts for the LED, which is kinda daft, but oh well).

So i've decided to make my own, with stuff i had lying around. Sawing isn't my thing, plus, i didn't have any scrap PCBs to saw. Plus, white and red LEDs shining through a green or yellow PCB? Yish.

I did, however, have this:


It's a plastic pad meant for furniture. Obviously, the two plugs are a nuisance and the whole thing is much wider than the motor mount, but otherwise, it looks like precisely the thing i need. So:


… from one came many. Well, two. The color makes for a somewhat jarring contrast on black arms, but hey - it does its job:


Coming up next: first flight (hopefully).

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  • It's the stock jdrones/diydrones arducopter frame. Check store.diydrones.com and www.jdrones.com.

  • Where do you get the frame?

  • Ante, great post, good info - you saved me some time on my build today!  Thanks,



  • Maybe, if i manage to get it stable enough to hold a camera with one hand ;)

    Or maybe if i manage to film the prop vibration and mistracking blades.

  • Yeah Good Job!   Will part 4 Have a Video?

  • Oh, wow! Thank you :)
  • 3D Robotics
    Ante: This build log is really excellent--many thanks! I think it's the best I've seen.

    I've linked to it in the manual here:
  • @T.D.: I've had my share of problems with ESCs too. One of them was faulty and i couldn't find a replacement locally, so i've ripped two of them out and replaced them with 30A Hobby Wings. They're mixed now - 30A Hobby Wings on front and rear, 20A jDrones on left and right. So far (judging from the initial quick hover test), the mix seems to be working just fine.

    @Gord Likar: Yeah, looking at that distro board made me a bit queasy as well. I was thinking about maybe spraying or painting some lacquer or vinyl on the traces. Although... most people seem to be running their ArduCopter frames with unprotected PDBs just fine, and the PDB is buried pretty deep under other components (there virtually isn't a single face of it that's exposed directly).

    I had a quick hover test in a yard covered by pretty tall, wet grass (it was raining a few hours earlier). And there were no ill effects on any of the electronics. I don't really plan on using the quad in wet conditions anyways (for now).
  • Gord: as you can see in the 6th picture the board is secured between two plates, there is now chance that anything touches it
  • Nice post, very informative. Don't mean to be presumptuous, but isn't the power distribution board an accident waiting to happen. Exposed as it is, or do you normally seal it up from the elements? I splashed water on my China built inverter tig welder. Twenty minutes after it was turned off suddenly all the lites in the house went off. Turned out that the switch turns off the inverter electronics but not the power supply. A drop of water got between the can of a capacitor and a grd. plane. Burnt up a patch of copper. Sorry if I went off topic - it's sort of related.
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