Saturday, June 6, 2015

The Life, Death, and Rebirth of a Quadcopter.

      Some time ago, my job required the use of a “drone” to do some visual survey work.  Research for that project led us to the DJI Phantom FC40.   That project went off without a hitch, and the FC40 stayed with me as I gradually paid the company back for the purchase.  This thing was a great platform for aerial photo and video!

Here is is in its original configuration.  One photo is a stock pic from DJI’s website, and the other is from a night flight I did here at home.13H-DJI-Phantom-RTF-58G-With-FC40-2

original-fc40-night-flight_17238965534_oI ran the FC40 thru many recharges, picked up a second battery pack, and did some very cool flights into cloud cover.  When the FC40 disappeared from view, I had a reasonable certainty that its GPS system would be able to bring it back home.

From the beginning I viewed the FC40 as really fancy training wheels, knowing as soon as I flew it the first time that I was hooked.  More RC flight definitely lies in my future!


Here is a video tour of our yard from March 2015.  Pay no attention to the people in the driveway.


Notice tho, that I speak of the FC40 in the past tense….   That is not an accident.  In April of 2015, I had done some repair work on the FC40.  After some hard landings the legs were cracked, as was the body shell where the legs attached.  So I got new legs for it, a new body shell (which I painted red), and rebuilt it.     While I was at the rebuild, I also added a 2-axis gimbal so that my videos would stabilize and I would be able to tilt the camera down.


   This image was taken as I rebuilt it, just a few days before the final tragic crash.  Note the gimbal hanging under it, and the altimeter mounted out front on a carbon-fiber and balsa outrigger.  This pic shows the red casing still open, as there was still some wiring to do.


   On doomsday, as I took it out for its first test flight since the rebuild, I had a stock battery in the compartment and the camera mounted to the gimbal for testing.  It was not filming however.  I wish it had been, I might have more of an idea what happened.

The FC40 lifted off from the ground, and hovered at about head height for a few minutes as I carefully tested the controls in each direction and worked the camera gimbal up and down a few times.   Seeming to have everything under control, I eased it into forward flight.  This is where everything went wrong.

The quadcopter suddenly went into full climb and took of to the south.  As soon as I saw what was happening, I pulled the mode switch out of GPS mode and back into “ATTI” (attitude control with no GPS).  This done I was able to turn it and begin bringing it down.  However, once it was turned to face back toward home it kept on coming full speed.  When it hit the side of the house, it appeared to be up on its side, as if it was trying to accelerate for everything it had.  The noise was horrendous, and I will probably never forget the sad slide to the ground.  Given the behavior, I had either a terrible GPS malfunction or the ‘Center of Gravity’ was way wrong.  Either way, I only had control over climb, roll, and yaw, but not pitch.  And climb control was not responding either right at the end.

    The wreck sat on a shelf for a couple weeks, while I just looked at it and debated with myself how to rebuild it.  Fast forward a month……

Meet the Phoenix.  Rising from the ashes of the smashed FC40, using the motors, props, camera, and batteries of the FC40.  And all the lessons learned…..









   This new quadcopter has a much more advanced flight computer, a telemetry radio that talks back to my tablet,  and a Sonar module that gives it more accurate altitude readings than the onboard barometer.  The mast sticking up near the back is the GPS antenna and compass.

  The telemetry system is a USB module that can also plug into a computer, and it is with that that I do calibrations and programming of the flight controller.  When running on the tablet, it overlays the aircraft position on a google map, and displays a dashboard of flight data to the right.  The smaller screen (my phone) recieves the image from the FC40 camera, just as it did before.


   Still to come on this newly reborn quadcopter:   A 2-axis gimbal ( I still want stabilized video), and maybe a GoPro camera instead of the DJI unit.  

    The Sonar is still in test mode, and I am waiting on a software patch (for the flight computer) to come out before I do more than careful test flights in the driveway.  So far, it has flown once and had zero problems.  Once I get comfortable with it in this form, I may upgrade the motors and props to larger models that can lift more battery.  More battery = longer flights.  The frame I chose can take up to 12” blades, which should lift more than the current 9” set.


P.S.  Please don’t call them “Drones”!  That word scares people, and makes the media foam at the mouth.  Call these the more accurate term “Quadcopters”.   Anyone who is involved in the hobby could go on at length why the quadcopters are very different from the “drones” that the military uses. 


P.P.S.   For some entertaining reading on RC technology, check out the website for the flight controller I am using.

Friday, January 30, 2015

“The Committee of the Whole” or “Parallel Processing in My Head”

I heard an interesting statement the other day.  In a discussion about marketing, the internet, and the changes happening over the last few years the concept came up of what really makes ‘ME’ an individual.  Marketing companies think they know who we are, and how to sell us things.  And certainly they can predict, on average, how people will react to this message or that.  But can they really target an individual, predict his tastes, his reactions to a given subject or situation?
The commentator stated, and I agree, that they cannot.  That it is impossible for anyone not riding around in your head to know what is really going on.

He used the phrase “The committee of the whole” to describe his perception of his own individuality.  His concept of himself was a hundred different ‘people’ in his head, each one specializing in a certain set of experiences.  He describes his sanity as the ability of all those ‘people’ to reach a consensus.  I found that it really resonated with my own concept of ‘ME’.  In my head are hundred of variable components of myself, superimposed over one another in a sequence based on the circumstances of the moment.  The resulting cacophony is viewed by the outside world as ‘Jason’.  Our brains function as pattern recognition machines, and each pattern adds to the mix up. 

Consider the factors that might add to a situation:  1:How you feel today,  2:Your relationship with your mom, 3:The weather, 4:How you feel about some family event that is going on, 5:The room is noisy, 6: Some weird smell drifted past just now, 7:Your wife just gave you the raised eyebrows of doom, 8:The music from what you watched on TV last night.  All these factors add up to a really simplistic view of the current situation, but it is enough to make my point.

We might be able to make some broad, general predictions of our own or others behavior.  But there is no way we can read somebody’s mind or heart and really tell what they are thinking.  We, as sentient individuals, are so radically different from one another that it amazes me we are able to agree on what the color ‘red’ is.  Each one of us has constructed our thought patterns from scratch, with no frame of reference except the instinctive sequential pattern recognition system that our creator wired into our brains.  That’s it….   Every other part of our thought patterns are derived from the environment and teachings that surrounded us from the moment our brain became active.  Who teaches somebody to make comparisons?  Who teaches somebody to be creative?  So many things we take for granted.  And yet we have agreed on the set of protocols that we call language, social interaction, etc. and it works!  We can live and work together with relatively little confusion.  That is amazing!

Stop for a moment and consider what trains of thought are running in your head right now.  Not the primary “read this strange article on this dude’s blog” process, but all the lower priority processes running in the background.  For example, in my head at any given time are my personal internal soundtrack  (star wars music, or Orf’s Carmina Burana, DaftPunk, etc.); a working model of the customers Cisco router that I just had to work on; the installation process for the computer parts I will likely have to install on my next service call; some material discussed at a congregation meeting last night; a way to modify my quadcopter to make it fly better; the road I will have to take in a few minutes to meet my boss and pick up the part to install on that next service call; why my spellchecker cant handle the word ‘quadcopter’; the slight ringing in my left ear from an ear infection; a joke my wife told me this morning; and currently moved to the front is the pile of ideas that are becoming this blog post.  All this stuff seems to be simultaneously running in parallel.

Sometimes we joke about ‘'’the voices in our heads’, and yet with all this stuff going on its all in my own voice.  Or at least those parts of it that have words.  Lots of things I think about in the abstract are more like 3d models with lots of moving parts.  But each 3d model, voice, or point of view is always clearly my own.

Yesterday when I first began considering all this the mashup of thoughts was completely different, and I wondered “with all this stuff buzzing round in my head, how can I ever concentrate on anything, solve any problems?”  I don’t have a clue…  Does every person in the world have this circus going on in their heads?