greghgradwell

8. The Dolt of Volt

Throughout my career, I've had the nasty habit of holding on to preconceived notions for far too long without questioning their validity. Often times, I will let a single bad experience with a product or technology cause me to discount it for months or years, until I am introduced to it again and realize what I've been missing. Sometimes I just make a boneheaded decision up front and then live with it (one of the many dangers of working mostly alone). And thus was the case when it came to me and voltage regulators.

Buck the trend

I don't know why, but I've got a propensity for step-down regulators. Not just, like, in general. That would be weird. But if one of my devices needs a particular voltage, I'm more inclined to use a step-down (buck) converter than a step-up (boost) converter. Honestly, I think it's just because in my mind I've managed to conflate voltage with gravity, and OBVIOUSLY it's easier to go downhill. In my defense, buck converters tend to be more efficient than boos

greghgradwell

9. Con Air(frame)

1

I've been reading imagining all your feedback, and I couldn't agree more. The action movie references have really dwindled lately, and it's unacceptable. The engineering should probably take a back seat. Hey, you want to feel old? Con Air came out in 1997. Oof.

2

Airframe Integration

Alright, down to business. Today we'll be commiserating about how difficult it can be to take all your hardware from the bench and mount it in your vehicle. It's like when you see a gigantic couch at Costco that looks like it will fit in your studio apartment simply because it's surrounded by 140,000 square

greghgradwell

10. Plan it, Janet!

Is it weird that two of my favorite fictional characters are both named Riff Raff? Well, technically one them is real, but he goes so hard in the paint that he makes me wonder if maybe I'm the one who's fabricated.

1

Unfortunately we're not going to be discussing the amazing freestyle that is "Introducing the Icon". Instead we will talk about the far less exciting topic of knowing where you are and where you're going (lest you end up someplace else). But don't worry, this is not a self-help seminar. Unless you are an autopilot, in which case the Singularity has arrived and I would like to be the first to welcome our robot overlords.

They're All Going To Laugh At You

If there is one thing I can count on when it comes to testing my inventi

greghgradwell

11. Kibbles 'n Wits

Welcome back! If you noticed that there wasn't a write-up last week when there should have been, then I think you're the only one. So congratulations, and please head over to the online store where you can pick up a free t-shirt using the coupon code THEREISNOSTORE. Unfortunately, I am still waiting on some new hardware to arrive that will allow me to illustrate the next step in the journey. So this post is a bit of an interlude, although it is still relevant to the autopilot development. We're going to have a quick discussion on the subject of dogfooding. If you're not familiar with the concept (and have an aversion to hyperlinks), it refers to the practice of using (and relying on) the product you are developing. For example, if I were making an email client (is the name G-mail taken?), as soon as I had a viable prototype I would begin to use it for all of my emailing needs. And although I don't have much experience in deve

greghgradwell

12a. Real to Reel

Welcome back, everyone! I hope you all enjoyed not leaving the house for the holidays. Isn't it crazy that people used to wear pants like every day? Wild.

During the break I finally got hold of the new computer I needed to help make this next demo possible. For starters, about a month ago I switched simulators, from X-Plane 11 to RealFlight 9.5. In case you're not familiar with RealFlight, it is an RC flight simulator, designed to recreate the experience of flying model airplanes (from the comfort of your home). If you've thought about getting involved with RC but don't know where to start, this is a great tool. It does an impressive job of replicating the RC experience, with the added benefit of not having to cry over all your crashed airplanes. But why did I choose to switch simulators? After all, you know I've cried plenty of tears over destroyed aircraft, so that ship has sailed.

• The aircraft in RealFlight are the same scale as the vehicles I will be t

greghgradwell

12b. A Eye in the Sky

Welcome to the thrilling continuation of our RealFlight simulator discussion. If you remember from last time (I had to go back and look too), we were able to capture video from a downward-facing view in RealFlight and transmit its data via UDP. These images could be collected by a separate process, thereby creating the presence of a third-party "camera". Now we will actually put that camera to work. To give you some context, here's a quick glimpse of what the camera sees on takeoff:

Now somewhere out in the grass lies a giant red circle. Our camera has been equipped with a clever algorithm to identify this red circle and tell the aircraft to orbit around it. You know what's cool about game engines? The pixels are perfect. So it really only takes like 4 lines of OpenCV code to find the circle. The hardest part is calculating the distance from the aircraft to the circle (whi

greghgradwell

13. 1+1=1

No need to pull out your calculator, folks, the math here isn't literal. Today we're talking about how it was possible to add a multirotor controller to our fixed-wing autopilot in just 4 days thanks to the awesomeness of Elixir. Now, if you're thinking "4 days is not nearly enough time to make a good multirotor controller", you're absolutely right. Let's call it the Little Caesar's Hot-N-Ready Controller.

I mean, I absolutely love their pizza, but certain (former) friends of mine... Anyway, just to prove that the controller isn't terrible, I offer you a video of this quadcopter flying in RealFlight. It's the same mission as the one we've used for our Cessna 150, with a bonus orbit added in the middle. But if you don't have two minutes to spare, I'll save you the trouble: it flies just fine. Would I trust this controller on a real quadcopter that had