A Hackable Drone Without All The Wiring

May 2, 2020 by Danie Conradie 13 Comments

Drones have come a long way in the past decade, and a lot of the pioneering work that made them mainstream was done by individual hackers and small teams. This often involves cobbling together components into flying crow’s nests of wiring. To streamline things a bit for hackers, the team at Luminous Bees are working on Ardubee, a small 3″ drone designed from the ground up for hacking.

The Ardubee is built around a single PCB that also acts as the frame of the drone. Onboard is an STM32F427 microcontroller, IMU, barometer and compass, ESCs, ESP8266 for telemetry, and a downward-facing range finder. It’s ready to connect to an SBUS RC receiver and a range of pluggable modules are in development to expand the drone’s capabilities. It’s designed to run the open-source Ardupilot software, which we’ve seen in so many DIY autonomous vehicles. Power is provided by a single 18650, which will probably limit higher speed maneuverability a bit but should be fine for the slower precision flight that such a drone is likely to be used for.

The team already has a swarm of larger 5″ drones that they developed for light shows. In the process they developed their own Ultrawide-band indoor positioning system, which will also be available for the Ardubee. They hope to launch a Kickstarter campaign soon and are asking for input from the community, so they can know what features need to be prioritized. We look forward to seeing where this project goes!

Autonomous vehicles are a popular topic around here for air, land, and water, and we have no doubt there will be many more.

Thanks for the tip [Andreas]!

Giant Scale RC A350 Airliner Using Carbon Fibre And 3D Printing

April 29, 2020 by Danie Conradie 16 Comments

Large scale RC aircraft are pleasure to see on the ground and in the air, but putting in the months of effort required to build them requires special dedication. Especially since there is a real possibility it could end up in pieces on the ground at some point. [Ramy RC] is one of those dedicated craftsman, and he has a thing for RC airliners. His latest project is a large Airbus A350, and the painstaking build process is something to behold.

The outer skin of the aircraft is mostly carbon fibre, with wood internal framing to keep everything rigid. The fuselage and winglets are moulded using 3D printed moulds. These were printed in pieces on a large format 3D printer, and painstakingly glued together and prepared to give a perfect surface finish. The wing surfaces are moulded in flat section and then glued onto the frames. [Ramy RC]’s attention to detail is excellent, making all the control surfaces close as possible to the real thing, and retractable landing gear with servo actuated hatches. Thrust comes from a pair of powerful EDF motors, housed in carbon fibre nacelles.

This project has been in the works for almost 5 months so far and it looks spectacular. We’re looking forward to the first flight, and will be holding thumbs that is remains in one piece for a long time. See the video after the break for final assembly of this beast.

For the next step up from RC aircraft, you can always build your own full size aircraft in your basement. If you have very very deep pockets, get yourself a private hangar/workshop and build a turbine powered bush plane.

Thanks for the tip [tayken]! Continue reading “Giant Scale RC A350 Airliner Using Carbon Fibre And 3D Printing” →

A DIY Functional F-35 Is No Simple Task

April 27, 2020 by Danie Conradie 19 Comments

The advent of affordable gear for radio-controlled aircraft has made the hobby extremely accessible, but also made it possible to build some very complex flying machines on a budget, especially when combined with 3D printing. [Joel Vlashof] really likes VTOL fighter aircraft and is in the process of building a fully functional radio-controlled F-35B.

The F-35 series of aircraft is one of the most expensive defence project to date. The VTOL capable “B” variant is a complex machine, with total of 19 doors on the outside of the aircraft for weapons, landing gear and thrusters. The thruster on the tail can pivot 90° down for VTOL operations, using an interesting 3-bearing swivel mechanism.

[Joel] wants his model to be as close as possible to the real thing, and has integrated all these features into his build. Thrust is provided by two EDF motors, the pivoting nozzle is 3D printed and actuated by three set of small DC motors, and all 5 doors for VTOL are actuated by a single servo in the nose via a series of linkages. For tilt control, air from the main fan is channeled to the wing-tips and controlled by servo-actuated valves. A flight controller intended for use on a multi-rotor is used to help keep the plane stable while hovering. One iteration of this plane bit the dust during development, but [Joel] has done successful test flights for both hover and conventional horizontal flight. The really tricky part will be transitioning between flight modes, and [Joel] hopes to achieve that in the near future.

The real Lockheed Martin F-35 Lightning II project is controversial because of repeated budget overruns and time delays, but the engineering challenges solved in the project are themselves fascinating. The logistics of keeping these complex machines in the air are daunting, and a while back we saw Marine ground crew 3D print components that they were having trouble procuring through normal channels.

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The Drone That Can Play Dodgeball

March 23, 2020 by Rich Hawkes 10 Comments

Drones (and by that we mean actual, self-flying quadcopters) have come a long way. Newer ones have cameras capable of detecting fast moving objects, but aren’t yet capable of getting out of the way of those objects. However, researchers at the University of Zurich have come up with a drone that can not only detect objects coming at them, but can quickly determine that they’re a danger and get out of the way.

The drone has cameras and accompanying algorithms to detect the movement in the span of a couple of milliseconds, rather than the 20-40 milliseconds that regular quad-copters would take to detect the movement. While regular cameras send the entire screens worth of image data to the copter’s processor, the cameras on the University’s drone are event cameras, which use pixels that detect change in light intensity and only they send their data to the processor, while those that don’t stay silent.

Since these event cameras are a new technology, the quadcopter processor required new algorithms to deal with the way the data is sent. After testing and tweaking, the algorithms are fast enough that the ‘copter can determine that an object is coming toward it and move out of the way.

It’s great to see the development of new techniques that will make drones better and more stable for the jobs they will do. It’s also nice that one day, we can fly a drone around without worrying about the neighborhood kids lobbing basketballs at them. While you’re waiting for your quadcopter delivered goods, check out this article on a quadcopter testbed for algorithm development.

Drones Can Undertake Excavations Without Human Intervention

March 16, 2020 by Sharon Lin 4 Comments

Researchers from Denmark’s Aarhus University have developed a method for autonomous drone scanning and measurement of terrains, allowing drones to independently navigate themselves over excavation grounds. The only human input is a starting location and the desired cliff face for scanning.

For researchers studying quarries, capturing data about gravel, walls, and other natural and man-made formations is important for understanding the properties of the terrain. Controlling the drones can be expensive though, since there’s considerable skill involved in manually flying the drone and keeping its camera steady and perpendicular to the wall it is capturing.

The process designed is a Gaussian model that predicts the wind encountered near the wall, estimating the strength based on the inputs it receives as it moves. It uses both nonlinear model predictive control (NMPC) and a PID controller in its feedback control system, which calculate the values to send to the drone’s motor controller. A long short-term memory (LSTM) model is used for calculating the predictions. It’s been successfully tested in a chalk quarry in Denmark and will continue to be tested as its algorithms are improved.

Getting a drone to hover and move between GPS waypoints is easy enough, but once they need to maneuver around obstacles it starts getting tricky. Research like this will be invaluable for developing systems that help drones navigate in areas where their human operators can’t reach.

[Thanks to Qes for the tip!]

An Epic Story Of 1980s FPV Flight

March 13, 2020 by Jenny List 8 Comments

A staple of today’s remote-controlled flight is the so-called FPV transmitter, allowing the pilot of a multirotor or other craft to see the world from onboard, as a pilot might do. It’s accessible enough that it can be found on toy multirotors starting at not much more than pocket money prices, and reliable enough that in its better incarnations it can send back high definition video at surprisingly long range.

In case you think of FPV flight as a recent innovation, the video below the break from [Larry Mitschke] should come as a revelation. In 1986 he was a bona-fide rockstar playing in a band, whose radio-controlled flight hobby led him into creating an FPV system for his planes and soaring above the Texas countryside at significant distance from his base while flying it watching a CRT screen.

The video is quite long but extremely watchable, all period footage with his narration here in 2020. We see his earliest experiments with a monochrome security camera and a video sender, and a whole host of upgrades until finally he can fly three miles from base with good quality video. 70 cm amateur TV makes an appearance with a steerable tracking antenna, he even makes a talking compass for when he loses himself. It’s an epic tale of hacking with what seems rudimentary equipment by our standards but was in fact the cutting edge of available video technology at a time when the state of the video art was moving rather fast. This is the work that laid the path for today’s $30 FPV toys, and for flying FPV from space.

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Cheap Strain Relief By Casting Hot Glue In A 3D Print

February 11, 2020 by Donald Papp 52 Comments

[Daniel Roibert] found a way to add cheap strain relief to JST-XH connectors, better known to hobby aircraft folks as the charging and balance connectors on lithium-polymer battery packs. His solution is to cast them in hot glue, with the help of 3D printed molds. His project provides molds fitted for connectors with anywhere from two to eight conductors, so just pick the appropriate one and get printing. [Daniel] says to print the mold pieces in PETG, so that they can hold up to the temperature of melted glue.

The 3D models aren’t particularly intuitive to look at, but an instructional video makes everything clear. First coat the inside surfaces of the mold with a release agent (something like silicone oil should do the trick) and then a small amount of hot glue goes in the bottom. Next the connector is laid down on top of the glue, more glue is applied, and the top of the mold is pressed in. The small hole in the top isn’t for filling with glue, it’s to let excess escape as the mold is closed. After things cool completely, just pop apart the mold (little cutouts for a screwdriver tip make this easy) and trim any excess. That’s all there is to it.

One last thing: among the downloads you may notice one additional model. That one is provided in split parts, so that one can make a mold of an arbitrary width just by stretching the middle parts as needed, then merging them together. After all, sometimes the STL file is just not quite right and if sharing CAD files is not an option for whatever reason, providing STLs that can be more easily tweaked is a welcome courtesy. You can watch a short video showing how the whole thing works, below.

Continue reading “Cheap Strain Relief By Casting Hot Glue In A 3D Print” →