gallinazo.flightgear.orgCurt’s Blog | Aviation and technology ramblings, and sometimes other things.

Curt’s Blog About Categories Model aviation, technology, and other stuff Here are some things that I’ve worked on or thought about. Most of this expresses my love of aviation, love of coding, and love of puzzling through tricky problems. Maybe something here will be interesting, helpful, or spark further thought someday. Most of the code described in these posts can be found on github. Nov 24, 2021 Dynamic Mode Decomposition Fundamentals Fundamentals of Dynamic Mode Decomposition (DMD) May 26, 2021 Flitetest DR1 Triplane Apr 11, 2021 Simplicity in UAS Flight Controller Design Simplicity is an important design goal. I wrote a different post explaining why. How might this principle beconsidered when design a complex system like a UAS autopilot. Apr 11, 2021 Simplicity in Design This is the main point of this post: Simplicity is an important design goal that is often overlooked. Mar 10, 2021 Camera as a sensor Horizon tracking and constructing a virtual gyro. Nov 16, 2020 Virtual Choir Maker There is nothing more magical and wonderful than when our voices unite. Nov 15, 2020 Faith, Music, and Politics The songs we sing Apr 25, 2019 Simple Vignette Correction From wikipedia: In photography and optics, vignetting is a reduction of an image’s brightness or saturation toward the periphery compared to the image center. Apr 12, 2019 DJI Phantom 4 Pro camera vs. Sony A6000 Recently I flew a DJI Phantom 4 Pro v2 head to head with an in-house (U of MN AEM UAS Lab) developed fixed wing UAS. This comparison isn’t entirely apples to apples, but maybe someone will find it useful. Mar 18, 2018 Almost, but not entirely real-time process control with Linux. First, if you are interested in doing real time process control on Linux, go watch this awesome presentation. This is way more important than reading my post! Do it now! Jan 12, 2018 New Hardware Design Project Feb 11, 2018 update: After some amount of tearing my hair out and some help from the beaglebone IRC community, I have the pocketbeagle UART2 configured and working to my external connector. Telemetry is up and running! I also plugged in an SBUS receiver, verified it is getting power correctly, bound it to my transmitter, and then verified the system is seeing my pilot inputs correctly. Next up: verifying all 8 pwm output channels. Jan 11, 2018 Adventures in Aerial Image Stitching Episode #7 Nov 22, 2017 Adventures in Aerial Image Stitching Episode #6 Generating survey area coverage routes Nov 20, 2017 Celebrating the 4000th git commit! Nov 7, 2017 Aerial Survey Flight (with Augmented Reality) Basic Details Oct 4, 2017 Spin Testing Wikipedia Spins : In aviation’s early days, spins were poorly understood and often fatal. Proper recovery procedures were unknown, and a pilot’s instinct to pull back on the stick served only to make a spin worse. Because of this, the spin earned a reputation as an unpredictable danger that might snatch an aviator’s life at any time, and against which there was no defense._ Sep 11, 2017 Sunset Flight This is Skywalker Flight #74, flown on Sept. 7, 2017. It ended up being a 38.5 minute flight–scheduled to land right at sunset. The purpose of the flight was to carry insect traps at 300′ AGL and collect samples of what might be flying up at that altitude. Sep 6, 2017 Field Comparison of MPU6000 vs VN100T The U of MN UAV Lab has flown a variety of sensors in aircraft, ranging from the lowly MPU-6000 (such as is found on an atmel based APM2 board) all the way up to an expensive temperature calibrated VectorNAV VN-100T. I wish to present a quick field comparison of these two sensors. Aug 28, 2017 Drosophila-nator (Prototype) This is a joint Entomology / Aerospace project to look for evidence that Spotted Wing Drosophila (an invasive species to North America) may be migrating at higher altitudes where wind currents can carry them further and faster than otherwise expected. Aug 25, 2017 Flying on the Edge of a Storm Aug 25, 2017 Flying on the Edge of an Eclipse (2017) Photo credit: Doug Olson Jun 6, 2017 Adventures in Aerial Image Stitching Episode #5 Last Friday I flew an aerial photography test flight using a Skywalker 1900 and a Sony A6000 camera (with 20mm lens.) On final approach we noticed a pair of deer crossing under the airplane. I went back through the image set to see if I could spot the deer in any of the pictures. I found at least one deer in 5 different shots. Here are the zoom/crops: Mar 13, 2017 Continuously Self Calibrating UAV Compass Feb 13, 2017 Autopilot Visualization: Flight Track Circling back around to see our pre-flight, launch, and climb-out trajectory. Jan 21, 2017 Zombie Door Jan 10, 2017 Failure is not fatal Dec 15, 2016 Synthetic Air Data (an afternoon hack) Air France #447 Dec 1, 2016 Howto: Action Cam HUD overlay In this post I share my process and tools for creating HUD overlays on a flight video. Here is a quick overview of the process: (1) Calibrate your camera, (2) Extract the roll rate information from the flight video, (3) Automatically and perfectly time correlate the video with the flight data, (4) Render a new video with the HUD overlay. Nov 30, 2016 Autopilot Visualization Jul 23, 2016 Mistakes! Jan 13, 2016 Automated Movie Frame Extracting and Geotagging This is a short tutorial on an automated method to extract and geotag movie frames. One specific use case is that you have just flown a survey with your quad copter using a 2-axis gimbal pointing straight down, and a gopro action cam in movie mode. Now you’d like to create a stitched map from your data using tools like pix4d or agisoft. Oct 21, 2015 Image Stitching Tutorial Part #2: Direct Georeferencing What is Direct Georeferencing? Oct 20, 2015 Image Stitching Tutorial Part #1: Introduction Oct 7, 2015 Flight Milestones Congratulations! Feb 15, 2015 APM2 Sensor Head Jan 26, 2015 PBY Catalina January 27, 2015 Jan 12, 2015 Sonic 64 Hobbyking Sonic 64 Dec 31, 2014 Polaris Ultra Manufacturer : Model Aero Sep 16, 2014 Coding and Complexity Norris Numbers Sep 15, 2014 Cutting the Cord Update: 10/01/2014 Jun 25, 2014 Adventures in Aerial Image Stitching A small UAV + a camera = aerial pictures. Mar 13, 2014 Smart Trainer Photo Shoot Design Observations Mar 13, 2014 Aerosky 185 Photo Shoot Mar 13, 2014 Aerosky 185 Build Notes I was interested in the Aerosky Sky Trainer 185 because it looks a lot like a Cessna 185. It has the 185 tail and is setup as a taildragger. Technically the rear window is not correct for a 185, but there are a lot of things you could nitpick if you really wanted to go there. The other interesting aspect of this kit is that it includes a full set of float for water operations. I live near a little lake so I am hoping this will fly well off water on a nice calm summer evening. Jan 4, 2014 Build Your Own PC (2014 Edition) The World is Constantly Changing Aug 3, 2013 Wisconsin Dells Jul 29, 2013 BackupPC, LVM, Cloning and Resizing Drives I recently went through the process of trying to move my entire 1.5 Tb BackupPC tree to a new drive. Here are some thoughts and comments from that experience. Jul 15, 2013 Spiraling Under Control One of the staples of fixed wing autopilots is the circle hold. A circle hold is the closest thing you can get to a pause button with a vehicle that must be in constant forward motion to stay aloft. There are a few hidden challenges in the task, including wind compensation and some unexpected coupling that can lead to weird looking oscillations if not handled well. People have been doing circle holds with UAV’s for a long long time, so I don’t bring anything new to the table, but it is always fun to play, err I mean experiment. Jun 25, 2013 RC Aircraft Precision Balancer and Work Stand This morning I whipped together a precision aircraft balancer” (like the Great Planes C.G. Machine”.) I built it out of $5.57 worth of PVC pipe and connectors from Fleet Farm and it probably took me an hour at the most. Jun 20, 2013 Sold the P-47 I sold my P-47 on...