So it's changed a bit from what came in the original box...

Now got the long legs on the copter, and the two-axis camera mount and a camera, so I can show everyone that I

can't fly very well...

Some points on this airframe that are going to serve me well:

• Lots of room underneath the main body for mounting various sensors (see below for notes)
• Now an X configuration
• Can adjust the balance a bit so I can accommodate a 6000maH battery (basically right under the center point of the frame
• Modified electronics stack with APM on the top shelf, and various radios in the middle.
• Got a new 2.4 radio GHz (Futaba) with a bunch of extra channels
• Still need to dress the wires so it looks less like a cat toy
• need to put the bracing back on the central body, else the legs get all saggy
• Added a spur arm at the back.

What's that for?

• I will mount the altitude sonar sensor back there, away from the electronic noise
• White ball gives me a visual marker so I can hazard a guess as to which way the copter is pointing

So what next?
Well, I'm having a lot of fun just flying the thing again. I had some electrical problems which made me take everything apart so I could get to the power distribution board (which then turned out not to be the problem).

I now have a copy of VMware Fusion and Windows, so I can for the first time run the mission planner on a computer that I own.  So I might explore some of that Waypoint navigation stuff as well.

But the longer term plan is also why I bought a radio with a bunch of extra channels. And deep down, why I wanted a "drone" in the first place.

I am working on adding a second Arduino (probably an APM because I've got a couple of the old ones and one of the new purple ones).  The second processor will run a sensor array under the main body, with sonar, infrared and possibly optical flow sensors pointing in many directions. This will let me do object avoidance, and dynamic path planning based on knowledge of where we are, where we want to be and what is happening around us. This processor will communicate with the main (original) APM using MAVlink commands, and will be controlled/adjusted by some of the spare channels on the radio. Will be interesting to run "multi-station MAVlink" with both the flight control and navigation computers listening on the same channel.  May end up using some of the secondary pins as flow control between the two APMs

This will let me use the main APM as a "flight control computer" which will take inputs from the R/C channels and the MAVlink, That's also why I'm moving the "altitude sonar" away from the main body, so with luck there won't be a lot of noise/cross-talk.

I will be using one of the spare r/c channels as a fail-safe switch (I might reuse CH 8) so that I can tell the flight control computer to ignore any input from the navigation computer; then I'm back to having a slightly over-weight Arducopter.

I've got some diagrams and notes up on Google Docs; once I get a few evenings to tidy it up, I'll share it here.

OK, OK, technically this is the second  flight..  First flight is here: http://youtu.be/0yKjbtFW-u4  ; I just like the second video better.

The vertical instability was caused by me not having the throttle curve set right on the Transmitter; by default it is just a straight line from 0 to 100. Setting the throttle curve to something more curvy makes it much more stable up and down.

Took me a while to get back to this, mostly because I was waiting for a  replacement motor installed after a brief but terminal "magic smoke event".

Thought I also needed a new ESC, but found a post here (http://diydrones.com/profiles/blogs/one-esc-is-not-like-the-others) which set me straight.

Spent a bunch of time at the workbench running through things, including

• pretty much all of the RC inputs need to be reversed for me (JR790)
• you really do need to arm the motors before anything happens; it is amazing how much time you will spend trying to figure why nothing is going on (but see previous point as to why I may have been having difficulty.
• taping and wrapping connections, I'm toying with the idea of heat-shrinking the motor wires to the end of the arm:

Next steps:

• Wrap the remaining motor wires
• Replace nylon screws with metal ones 
• Add XBee modules to airframe
• lots and lots of flying

Anyway, that's enough for now -- I'm off to fly some more...

Well, after a week busy at work (err, and running through Portal 2), it's back to the bench.

The second APM showed up, and this time I managed to solder the connectors on correctly.  That was a good feeling.

Got the IMU connectors on, hooked up the GPS and the magnetometer, and fired up the APM on the bench.  Ran several diagnostics successfully (using 2.0 Beta for now). Took  the numbers out of the GPS, plugged them into Google, and the little arrow was on my house. That was a great feeling.

Noticed that the magnetometer seems to oscillate around  ±8º ; don't know if this is a feature or something that is tweakable.  Time will tell. 

Next step is to put together the Quadcopter airframe, after which we get the joy of the first flights. Hope it will be less traumatic than my first flights in the 400-450 series helicopters.

Waiting on some connectors (Deans female) for the power distribution board so I can unplug and plug the ESCs rather than soldering/unsoldering them,  All my batteries use Eflite EC3 connectors, so I'll be getting a couple of EC3s as well.

Plans

My target for Block 1 is to have a stable platform which can "loiter" at a given position. This will involve the following steps, I think.

1. Manual flight, using my RC Tx to control the craft (hands-on).  Demonstrate that it will perform stable hover and low-speed level flight in the confines of my back yard.  Get some sense for the battery life, and try things like mounting two batteries in parallel.  See how badly the ESCs overheat (if they do).
2. Hands-off stable hover, under autopilot control.  Goal here is to get the craft to hover, maintaining altitude and orientation when I don't have my hands on the controls.   Program one of the channels in the Tx/Rx to get into and out of this mode.
3. Hands-off orientation changes.  Once I can maintain a stable hands-off hover, figure out how to turn 90 º to the left and right and back to an original heading
4. Return to starting point in autonomous stable slow fight. This involves:
   • Stable hands-off hover at starting point
   • controlled manual straight and level flight to some nearby point (line of sight, no obstructions, not too far)
   • Stable hover at far end point
   • slow level autonomous flight from "far end point" back to starting point
   • Stable hover at starting point
5. Ability to automatically self-land from a stable hover.

There should be enough programming, learning and tinkering there to keep me busy for a week month or two.

I'm also writing some Java code on the Mac to act as a base-station. When I get my XBees set up, I'll be taking real-time telemetry from the Coptermatic and ingesting it into some ground monitoring software. Idea here are to save the logs to a file in raw text form,   put up some sort of graphical displays using Graphite or similar, and possibly storing the log data in a MySQL database for later use.  Hey, complex solutions can be fun!

'll be posting some photos and (hopefully) flight videos next time.

Minor background before I start.  

I've been playing with wheeled robots for a while, using the Basic Stamp as a controller.   Just tinkering, and more interested in the software side of things (as well as having something that annoys the cat).  My enthusiasm died out about 7 years ago, then my son gave me a Lego Mindstorms NXT kit for Christmas, and I was off and running again. 

At about the same time, a co-worker got me started on radio controlled helicopters (Blade CP/2 to start with, moving up to Blade 400 and TREX-450 over the last few years).  You can't have too many expensive hobbies :)

Managed to do quite well at this helicopter hovering in the back yard, and was doing quite well until about a year ago when I flew my pride and joy into a tree and broke just about everything except the tree.

"I wonder," I wondered, "if it would be possible to combine my robotic hobby with my RC flying hobby?" 

Poked around teh intarwebs a bit, and ended up here looking at the APM and the Arducopter code. 

Thus started work on what I am now calling Coptermatic, the Automatic Helicopter.  (with apologies to Wallace & Gromit)

So off we go:

Got my workbench set up, got me new Weller soldering station set up, played with some Arduino programming for a practice, and decided that tonight was the night.  

I solder all the pins on the APM. I solder all 48 pins on the right angle servo connector (the three pin monstrosity on the end of the board).  I've got all the pins on the APM,  

But the servo connectors seem a bit fragile, and my attempts to test-connect a couple of servos and Rx connectors seems wonky.    Imagine my amusement when I discover that I've soldered the damned servo connector on backwards.  For that connector ONLY, the black plastic bit doesn't go flush with the top of the board.  What's worse, I compared what I was doing with the pretty picture in the instructions four or five times and didn't notice my error. 

OK, so now I am sort of stuck.   I'm an amateur with the soldering iron (more of a software engineer with a  predilection for tinkering).  I'm not at all sure how to unsolder 48 connections; I think I need something more than desoldering braid and bad language. 

The current plan (as blessed by my long-suffering and patient wife) is to use this APM as the brains for a small wheeled robot which I shall call the Pipbot (in honour of the Fallout series of games) and to buy another APM from DIY Drones for the 'copter. 

So a bit of a (not-so) cheap lesson in following instructions.  This hardware stuff is a lot less forgiving than software.