Tag: rc

This is part 2 of 2.  To see part 1, click here.

In part 1, I described the new sport of FPV Drone Racing.  In this posting, I’ll tell what it’s like to try and take those Youtube videos and star-eyed ideas and make them real – IE, build and fly my own drone.

Once I understood the details of what a 250mm racing drone was, I had to buy one. Getting parts and pieces and assembling the entire series from scratch was daunting. What sort of ESC’s, what sort of flight controller, etc etc.

I found an eBay posting for a configuration that seemed right. Motors, props, ESC’s, frame, flight controller, all the pieces were there, for $108, delivered.  Win!  I’m in. I hit purchase.

That was March 14th. Little did I realize, I had made a classic blunder that’s all too common in this new sport. The frame I ordered was from China, and would take at least 3 weeks to arrive. Agony! Oh well. Lets make the best of it. I spent the intervening time building out my secondary parts inventory. A transmitter and receiver. Batteries. A carrying case to hold it all. Charger. I would be ready.

Finally, the frame arrived, and it was time to get to work. I unpacked the (small) box and laid out all the parts. Have to admit, the box looked less than promising. After driving myself bonkers looking at FPV videos, talking with folks online, etc, this sure didn’t look like what I had hoped it would be.

Opening it up and sorting through parts, things started looking better. Everything was there, and it even looked pretty good. Machining was good, parts were as expected, all I needed to do now was put it together. I had chalked off the evening to do the assembly, and it took all of that to get from “piles of parts” to something that started to look like an actual drone.

Anyone who has ever built an RC model knows what comes next. Doesn’t matter that this thing you’ve dreamed about sorta looks like what you imagined, you have a long road between “Looks done” and “it’s in the air”. The first trick was wiring the power harness so all of the ESC’s would have power to drive the motors. Some drones use a Power Distribution Board (or PDB), but this particular configuration didn’t have one, so I needed to wire up my own. Lots of soldering later, I realized the power connectors on my batteries didn’t match anything I had, nor did they match the charger I was using. Arrrgh. I suppose this is what happens when you build something from scratch, on a platform that really hasn’t solidified.

Somewhere around here I joined up with the MakeIt Labs folks up in Nashua, NH. They have a pretty rabid drone group there, and these guys were unbelieveably helpful in guiding me up this steep learning curve. I learned that most folks use XT60 power connectors, so I ordered up a handful of those.

So, ready to go, right? Yeah, not so much. My FC (Flight Controller – a CC3D from the OpenPilot) needed to be programmed and calibrated with my motors and ESC’s. This is not a trivial process, and I was getting frustrated that my motors were not spinning up appropriately. Turns out, I had a blown ESC. ANOTHER BLOCKER. After much hand-wringing about ‘can you mix different kinds of ESC’s on a single quadcopter’, I took the plunge, ordered 4 more ESC’s, and after they came in, installed one onto the drone. More calibration, and… okay, now the motors are spinning under test, but are not responding to radio control at all. On the other hand, it LOOKED like a drone, smelled like a drone, it just… wouldn’t fly like one. (BTW, after sharing this picture, the folks at the lab were like “That’s a STUPIDLY large battery. You know most folks fly with a 1300mAh battery, right? You’ll save weight and space using a more appropriately sized battery). So, 2 new batteries ordered.

Here I have to give a bit of a shout out to the OpenPilot peeps.  I understand there’s a little back and forth in the community about who owns the software, who owns the boards, and the like, but the OpenPilot GCS (ground control station) software is outstanding – running flawlessly on my Mac and giving me enormous control and detailed information about my flight controller.  The CC3D controller itself can be had for around $25, and, as a geek who has seen some pretty complex little controller boards, what this thing can do is nothing short of amazing, for such a low cost.  Very fast signal processing, control, and durned good communication / feedback to the groundstation software.  The CC3D flight controller is being slowly replaced by the Revolution board, but that’ll be an upgrade for the future.  Right now, I love my little flight controller, and am so grateful to the developers and community that made it possible.

Eventually I got all the factors aligned, and my drone took to the air.  Flying Line Of Sight (or “LOS”) is the normal way people expect RC planes to fly.  Watch the craft in the air, learn the controls, and fly around.  My first few flights were just this… zipping around, feeling what it could do.  I quickly learned what most pilots learn – it’s easy to fly your craft when it’s oriented directly away from you.  Where left is left, right is right, forward is forward, etc.  But once that vehicle turns and is coming toward you, all the controls are reversed.  Thing flying toward you too fast?  You pull back on the pitch stick (pull it toward you) to slow it down and pitch up.  That’s not intuitive!  I still have not worked this out – and in talking with other new pilots, I’m not alone here.

Eventually though it was time for the next step.  First Person View, or FPV flying.  In a nutshell, my drone has a small digital camera mounted on the front, and that is in turn wired to what amounts to a television transmitter.  This signal can be sent back to a ‘groundstation’, or a set of goggles with a receiver and antenna.  After some back and forth determining how to use goggles with my glasses (I ended up removing my glasses and wearing the goggles in a way that puts the screens a half inch further away from my eyes than normal.  This works) – I was ready to fly.

This video is pretty much what happened.  Did I fly?  Yep.  Was I able to be ‘on board’ and see what the drone sees?  Sure enough.  Was it the leaping, “Lo, I have slipped the bonds of earth” experience I was hoping for?  Not even remotely. Next big lesson:  Flying FPV is REALLY REALLY HARD.  A drone doesn’t fly like an airplane – it doesn’t bank and swoop.  In a wind, it behaves erratically and unintuitively.  So naturally I crashed.  A lot.  Dozens of times.  And each time, something would come off, something would break, things needed to be tuned… it was… exhausting.

That video was made around 6 weeks ago.  Since then I’ve replaced all my motors, rebuilt the camera mount,installed a new camera and video transmitter, heck I’ve remounted virtually every component on the frame.

The result?  I’m… starting to enjoy it!  Flight times are up, crashes are down, maneuverability is comfortable – we’re not yet ready to go tearing through concrete tunnels, but I can make loops around the field and mostly not crash into trees now.  My drone is still tuned to a very basic level of responsiveness.  I’m not doing crazy flips and the like – and frankly, ain’t gonna do that anytime soon.  But… well, take a look at how I’m flying now.  This was in the same field as the first video.  Check it:

Am I super-pilot? Not even remotely. Am I starting to feel like this is fun, and lets me experience, in a weird way, what it means to fly? It comes close… and I’ll keep trying.

It started innocently enough. A video linked on youtube showing some “pilots” gathered in the woods. An obviously well organized group, with safety crews, a well marked course, and referees. The pilots were several guys sitting in camping chairs, with goofy looking goggles on, or staring intently into small video screens.

Then the racing started, and the viewpoint shifted to the nose of the craft zipping in and out of the trees. It immediately evoked memories of the speeder bikes from Return of the Jedi, tearing in and out and around trees in the forest. The craft in the video were lit up with LEDs that made them glow brightly… even as your competitor passed above you on a fast straight, or swung wide on a turn.

Quickly, other videos started appearing up showing similar craft and activities. People were getting together to race small remote controlled ‘drones’.  I was intrigued.  These were custom built, complicated radio control models, but I felt they were within my skill set to construct and fly.

I had to do this.

First though, I had to figure out what the heck I was looking at!  I was no stranger to radio control aircraft.  People have been building planes with cameras attached to them for ages.  I knew that in the last year or three, some Makers have build ‘quadcopters’.  Small, maneuverable aircraft that could move up, down, sideways, and spin in place either autonomously or via remote control.  As I saw these being demontrated, I thought the idea was interesting, but the limited flight time, carrying capacity, and expense were just not worth getting involved in.

Then several things changed.

First, the wide availability of Lithium Polymer, or LiPO batteries. In the Radio Control world, LiPO’s had been gaining ground, and in 2013 they’d reached a density and weight where they made sense on very small, light craft.

Second, small portable HD cameras were becoming more available. By far, the best known are the GoPro Hero Cameras, but more recently, the Mobius camera has become the unit of choice. It’s small, well built, has excellent resolution, and fits well on small flying vehicles.

Last but not least is the availability of relatively inexpensive First Person View, or FPV equipment. FPV had been possible in the past, but the equipment was bulky and expensive. Modern gear can be extremely small and light, and easily installed by a new model builder.

All these things came together to produce what can only be described as a skyrocketing interest in building small, highly maneuverable ‘drones’, getting ‘behind the wheel’ of one (via goggles or video link), and going flying. Or, even more fascinating… going RACING.

I had to do it.

I watched tons of videos on Youtube. This sport is still relatively new. Most races and groups have only been flying for 6-8 months. The equipment design and processes for building and flying are still being worked out, but the basics are pretty well set. I spent my first 2-3 weeks just understanding all the parts of a drone, what was needed, how they worked, and how things came together.

Here’s the gist of it.

First, there’s a heck of a lot of weird terminology.  Here’s a good glosssary of terms to start you off.

What is commonly known as a “Racing Drone” is a 250mm (that’s corner to corner) lightweight frame with 4 brushless motors on the limbs. The motors are told what to do starting with a Flight Controller, an on board computer that provides stability to the drone, as well as takes commands from the radio receiver, and tells the motors what to do.  The Flight Controller (or “FC”) communicates with Electronic Speed Controllers (or “ESC”) – one per motor – that varies the speed of the motor based on commands from the flight controller. Powering all this is a LiPO battery that’s usually set up to provide 5-7 minutes of flight time per charge. The drone receives it’s commands via radio link using a radio receiver, which is paired to a handheld radio transmitter the pilot carries.

That describes the drone platform itself, but if you want to do FPV, you’ll also need a camera (FPV cameras are small and relatively low resolution), a video transmitter and antenna, and a video receiver and display setup.

That, in a nutshell, describes an 250mm FPV Mini Racing Drone. From this basic design, many things can be added or enhanced. Adding an HD camera is very common (the HD camera records the flying sessions for viewing later. The pilot flies just via the FPV camera) – this is where the cool videos come from. Adding other features such as a GPS receiver, a system that can interface the flight controller data with the FPV display (called an On Screen Display, or OSD) can let the pilot see realtime data from the drone as it’s flying (Altitude, speed, position, battery level, distance from pilot, even an indicator showing the pilot how to get the drone back to them). These are fun additions, but aren’t required for racing (some pilots will argue having all that junk on the OSD can just distract you from the racing).

In addition to the parts needed to build a drone, every pilot has a whole infrastructure of materials to make the flying possible. A LiPO battery charger is required. Because LiPO batteries are pretty complex, the chargers tend to be fairly involved pieces of equipment, and pilots need to understand how a LiPO works, how it’s rated, what configuration it’s in, how to charge it, etc.

Spare parts are also a requirement. It’s common to break props many times a day, so keeping spares is a necessity. Zip ties, velcro straps, spare motors, ESC’s, these are all tools in the arsenal.

But enough about that, how’d I get from “What a cool thing!” to being out and flying?

That will come in my next blog post!

Update:  check out part 2 !