Return to Home

(Author’s Note: The following events took place earlier this year, prior to Maine’s Department of Agriculture, Conservation, and Forestry issuing new rules regarding the use of sUAS in state parks. If you intend to fly your sUAS in a Maine state park, I advise you to contact the DACF for information on getting permission.)

I made it to Popham Beach sometime after 4 AM. I had just enough time to walk from the car, find a good spot for my timelapse camera, walk over to Fox Island, and catch my breath before the sun came up. It was a perfect morning for filming. The skies were clear. There was barely any wind. It was near low tide, which was super important because I wouldn’t have been able to make it to Fox Island otherwise. And best of all, I was the only one around for as far as I could see. At this hour, I owned the beach.

The sunrise was spectacular. It came up slow and steady. I watched it as I finished off a bottle of water and listened to the waves crash against the rocks. It took about 10 minutes before I felt the light was good enough to launch my drone. I then positioned my landing pad (a square piece of plywood). I unpacked my Phantom and calibrated its compass. A quick hover to make sure it sounded normal. And then it was off!

Fox Island, for those who don’t know, is a small little rock outcropping that sits almost half a mile from the Popham Beach State Park parking lot. It’s only possible to get to during low tide. And it provides a magnificent view of the park in all directions.

After 15 minutes of flying around the island, I decided to fly the Phantom out a good distance over the water. I really wanted some footage of it coming back low, close to the waves.

At a distance of 1,534 feet, my Nexus 7 tablet locks up. Thinking it might have just been a frozen video feed, which happens sometimes if there’s bad interference, I tap the sticks a few times trying to elicit a change in the on-screen video. And then a few seconds later, the tablet reboots.

Panic.

I’m flying blind. I have no idea what the drone’s orientation is. Worse still, I flew it in the direction of the sun which meant I couldn’t see the thing even if it were 20 feet in front of me.

I press and hold the “Return to Home” button on the controller.

“Beep, beep, beep, beep….”

I scan the horizon looking for a sign of my little robot friend. Nothing.

“Please come back, please come back, please…”

An eternity passes by and the beeping on the controller stops. No other sounds but the crashing waves and my heartbeat pounding in my ears. “It gave up,” I thought. “It’s somewhere out there hovering above the water just waiting for its battery to die.”

I sit down, I lay the controller on the rocks, and then hang my head in defeat. It was lost. What would I do? I had hoped to start a photography business with this drone. How would I do that now? And how much crap is my wife, who already hated everything about this little hobby, going to give me?

“Bzzz…” So very faint. The sound would disappear almost as fast as it appeared. I scanned the horizon all around me. Nothing. “I’m hearing what I want to hear.”

“I’m effed,” I thought. More eternity passes.

I was just about to start packing up my gear when I suddenly heard, “Bzzz….” The sound was very strong now. But it was above me.

I looked up and there it was 200ft above my head. The Phantom came back! It was hovering awaiting my instructions. I immediately grabbed the controller and brought it down manually, very careful to land it on its little plywood landing pad. I shutdown the motors and powered down the battery. I picked it up in my arms and hugged it as if it were my child.

“Thank you! Thank you! Thank you! Thank you!”

The lesson, boys and girls, is always ALWAYS set and reset your home location. Make sure “Return to Home” is configured the way you want it to work. And do one better than me – test it before you actually need to use it. It can, and probably will, save your drone one day. Also, line-of-sight can be lost without something getting between you and the drone. That’s worth keeping in mind too.

On the plus side, video was being recorded the whole time. The entire moment at which the Phantom rotates, rises, and begins its voyage back to me was captured. And although it isn’t exciting for most people to watch, for me it’s the most dramatic.

Practice Flight – 05/27/2017

I took my 250-class quad to Popham Beach over the holiday weekend. It was a little chilly. And it was windier than I would have liked. But, the quad performed like a champ.

Here’s the video. Enjoy!

Tech Specs:

  • Quad Size: 250mm
  • Quad Weight: 976.7 g (she’s a fatty, I know)
  • FPV: Fatshark Predator V2
  • Recording Camera: RunCam 2
  • FC: Flip MWC 1.5
  • ESCs: ReadyToFlyQuads F-30A
  • Motors: RTF Motor 2208 – 2300KV
  • Props: 5×4.5×3 Bullnose
  • Batteries: Turnigy 2200mAh 25-35C 3S
  • Radio: FlySky FS-T6

-Shane

Review: The Barr Group’s “Embedded Software Training in a Box”

I first heard about the Barr Group’s “Embedded Software Training in a Box” at Dan Saks’ CppCon talk “extern C: Talking to C Programmers about C++”. During the Q&A portion of the talk, someone had asked about breaking into the embedded software industry. Dan suggested the Barr Group’s course as a possible first step. I’ve worked in the embedded software world for a while. And I recognize weak areas in my skillset. Always looking for opportunities to learn and improve, I decided to give this course a spin.

The Barr Group’s “Embedded Software Training in a Box” is a cheaper version of their four day, in-person “Embedded Software Boot Camp”. Both courses share the same material and the same exercises, but the boxed kit is self-directed. There is no instructor and no peer support. At the time of this writing, the “Embedded Software Training in a Box” is $899. That’s a whole lot cheaper than $2,399.00, which is what the in-person boot-camp costs – a price difference of about $1500, plus whatever travel expenses you’d otherwise incur.

The Barr Group’s website provides a syllabus for the boot-camp. Major topics you can expect to learn about include idioms for embedded programming with C, memory management, multitasking, and interrupt handling, real-time OS concepts, and a few other odds and ends sprinkled in for good measure.

The Unboxing

The following is a picture of what I received after purchasing the kit.




Within the box are five things – an RX63N Demonstration Kit from Renesas, ($105.19 from DigiKey at the time of this writing), a USB drive, an “Embedded Software Field Manual”, an exercise manual, and a quick-start letter.

The “Embedded Software Field Manual” is the cornerstone of this course. It’s intended to be the primary course material. This surprised me, however, as the field manual turned out to be a giant, spiral-bound print-out of all of the slides used in the boot-camp.

The USB drive contains a lot of things, including exercise projects, datasheets, various interesting magazine articles, a few e-books, and the Windows installer for IAR Embedded Workbench 7.0 – the compiler/IDE of choice for this course.

It’s worth noting that a license for IAR Embedded Workbench isn’t provided with the training material. In order to do any of the exercises, you have to obtain a trial license from IAR. Directions are included for how to do this. And there are actually two flavors of the trial license – a time boxed evaluation (30 days) and a code-size limited, time-unlimited evaluation. The training materials instruct you to choose the “Code size limited”, which is plenty sufficient for the exercises in this course.

The way the course works is that you read through the slides until you hit a “Hands-On” exercise. At that point, you’re redirected to the exercise manual which provides more details. Once you’ve completed the exercise, you return to the slides and keep going. Wash, rinse, repeat. There are nine hands-on exercises in total, and a “Cap-Stone” project at the end that’s intended to tie everything together. With the exception of the processor user-manual, the rest of the documentation on the USB drive is supplementary and can be read separately from the course.

Course Pros

  • The course covers a wide range of topics, including programming idioms, real-time OS concepts and scheduling algorithms, ADCs, UML state charts, interrupts, multitasking approaches, etc.
  • The Renesas demo board contains a variety of different types of components to play with.
  • Getting up and running with the Renesas board and IAR Workbench is super easy.
  • There are plenty of good supplementary articles and books provided on the flash drive.
  • The flow of the course feels very natural.
  • The hands-on projects are somewhat fun. (You can’t go wrong with blinky lights.)
  • Solutions to the exercises are provided.

Course Cons

  • As I said before, the “field manual” is just a collection of slides. Slides provide talking points. And without discussion around those talking points, a lot of information is lost. The vast majority of the slides are good. But there are a lot of places where more context is sorely needed. Sometimes acronyms are used without being defined, sometimes formulas are defined without any explanation of what they’re used for, and sometimes graphs are included that are just baffling. I confess I had to turn to YouTube at least twice for clarity on a few topics.
  • Many of the hands-on exercises are virtually impossible for the uninitiated to complete without looking at the solutions.
  • If you’ve never read a data sheet before, you may feel a bit “thrown in the deep end”. The course definitely doesn’t provide a gentle introduction in that regard. When the exercise manual says something like, “Familiarize yourself with such and such 50 pages of the processor data manual”, they really mean read all 50 pages.
  • No discussion of embedded Linux.
  • The tooling used for the course isn’t cross-platform. It requires Windows.
  • No course videos.
  • No online forum to discuss material.

Conclusion

This course is just OK, in my opinion. There are definitely some good nuggets of information. The exposure to μC/OS-III was new to me and I enjoyed that. But overall, I was kind of disappointed. The slide format didn’t really work for me. And the exercises, while interesting, sometimes felt a little disconnected from the “field guide” material.

The course could have benefited greatly from some online videos. At the very least, some discussion forums. For a $899 self-directed course this day and age, one expects such things.

The good news is that at the time of this writing if you’re interested in attending the in-person, boot-camp within a month of purchasing the boxed kit, the Barr Group will refund the cost of the kit so long as you bring it with you to the boot camp.

Do I recommend “Embedded Software Training in a Box”? It depends. If the company you work for has a good training budget and is willing to pay for it, sure, go for it. It’s not bad. If you’re paying out of pocket, however, I suggest maybe looking for alternative learning opportunities first.