Sunday, November 30, 2014

Quadcopter, it talks to computers, and it hovers!

Saturday morning, a package arrived. It had bigger motors in it. And, those motors came with all the right screws to mount them. So I got those installed.

Motors need something to make them spin. Those "should" be placed somewhere they'll get airflow.

The frame I'm going to be flying has the sprung lower chassis and the upper "x" frame. I think that to get the most benefit of the shock mounted upper "x" frame, I'm going to try to mount everything I can on the lower pod.

Also, to have the lightest install I can manage, I want to have the motor leads as short as I can manage.. that means mounting the speed controls close to the motors. The closest I can get the speed controls to the motor is on the wings of the pod.  I think they look good there too.

Quadcopters are not stable.  They need a controller to make them manageable.  And even then they can be a bit of an adventure.  As I'll explain later.

Our choice of controller is the Naze32.  They come soldered, and unsoldered, and this time.. we got the unsoldered version.  So out came the soldering gear.  Well.. actually SwitchElectricians soldering gear.

And here's the Naze32 mounted, properly, to my quad-copters top plate.  We chose to mount our controllers up there because the battery is less likely to bash into it, and an impact with the ground isn't likely to cause anything to come up and interfere with it.  Or at least that's the thought.

Mounting the boards where we did, also lead to some problems.  My board is inverted.  And the board assumes it will be right side up and looking forward.  However, that can be handled later.

While I had the soldering iron out, I built the power harness.  I want all of the motors to run the same, and I have a moderate dislike for the PDB (Power Distribution Board) systems out there.

PDB's have a limit on how much copper is available to pass power.  Given that these motors will only draw a maximum of 10 amps each, I doubt a PDB would be a big voltage drop.  Still, I don't like them, and I'm pretty good with a soldering iron.

My harness is a U shape of 14ga wire.  Each speed control is fed by 20ga wire.  I think it looks good, and it keeps the high amperage stuff away from the signal wires.  This setup still needs a few more zip ties.

It almost looks alive here.  Standing on it's tippy toes.  Here we are programming it for the first time.  Mistakes are being made as this photo was being shot.

For lack of damper balls, I have some rolled up cardboard and zip ties holding the "x" frame to the lower pod.  So for now the joint is rigid.  The receiver doesn't care if it gets shaken, so I mounted that on top.

I really like how the back end turned out.  There's an XT60 connector on there because that's what SwitchElectrican had on hand.  I use Deans connectors for the most part.  I'll be swapping that as soon as I get this thing home.

Testing the quadcopter didn't go very well.  Every time I got the throttle high enough to have it fly, it would sort of respond to inputs, then flip over.  Faster than I could do anything about it the heli was on it's top.

This happened three times.  I ate two props the first time, and another prop the second time.  And for the third time around, we flew on top of a towel, which saved the props...

The speed at which the thing was flipping made me think the thing was feeding back into itself wrong.  We sat down and watched a video on how to set up the Naze32.  And while we learned a bit from it, such as what "angle" and "horizon" modes were, that didn't seem to pin down why the thing was inverting so quickly.

And then we took a close look at the setup page.  Both SwitchElectrician and I had our boards in non-standard directions.  So any time the board tried to tip, the controller tried to compensate in a wrong direction.

Once we sorted out the proper directions, I was able to lift off and hover the thing.  However, due to the time of night, I wasn't able to really take it for a flight.

My advice to you, is make sure that your board knows what direction it's in on your airframe, and the motions you make with the airframe match what you see on the screen.

Oh look the quadcopter is home.  It needs a name.  I'm open to suggestions.

Next time, the quadcopter will get it's FPV rig, and it's 720p video camera mount.

Wednesday, November 26, 2014

Building a quadcopter: finding out what's missing.

A couple weeks ago, a youtube video surfaced of people racing quadcopters through the woods. Well, here's the video.

Kinda exciting isn't it? But what does a setup like that cost? How much effort would it take to do.  My buddy SwitchElectrician said he wanted to do it.  I...  well couldn't resist. 

I did some digging, and found a quad frame that looked good to me.  He and I both bought this:

 It's a good looking platform to me.  A solid X shape with a pod suspended on anti vibration balls.  The controller boards don't like vibration, so isolation is a good thing.  Amusingly, it's on the expensive end of quadcopter frames, at an astounding $20. 

Orders were placed.  Items were shipped.  SwitchElectrican and I both got our quad "kits" within a week.

Look, it's a flat pack Quadcopter.

The kit looks pretty complete.  Lets dig in.

SwitchElectrican had contacted me, and told me that his was missing some parts.  I was hoping mine wasn't going to be missing those bits.  So I start digging, and the disappointment sets in. 

You'll notice that the only paper in there is the little business card, with the picture of the quad on it.  There are no instructions, and that kinda matters on this thing, as we'll get to later.  And no damper balls. 

So I started with the bad, lets cover the good.  The aluminum standoffs are all perfect.  The screws and standoffs have good threads on them.  The screws are of high quality.  The milling of the FRP is almost flawless.  Suffice it to say, I'd buy this kit again, and again, and recommend it to others.

The bottom plate is some very thin fiberglass.  It's downright floppy.  But as you can see, it's got nice sharp edges everywhere, and no fuzzy bits like you'd get from a dull cutter.  I couldn't resist starting the assembly.  With eight standoffs, this should end up being a very rigid pod.
 After assembling the pod, I found that the top plate goes on the pod just one way.  This is where a manual would have been handy.  I think it would also help to dictate which side your camera should be mounted on.  

I couldn't help but throw a motor on, and a speed control, just to see what it looked like.  For now the build is stalled until I get the damper balls in. 
Next update should be the completed build, and the first hover. 

Thursday, November 6, 2014

Stinky stuff from China?

I love getting new stuff in the mail.  This time it was a stack of protoboards from China.  When I opened the package though, I was struck by the smell.  It smells like a zoo.  Weird...  Oh well, I get to build circuits tonight.