Your Quadcopter Has Three Propellers Too Many

While studying failure modes for quadcopters, and how to get them safely to the ground with less than a full quad of propellers, a group of researchers at the Institute for Dynamic Systems and Control at ETH Zurich came up with a great idea: a mode of flight that’s like the controlled spinning descent of a maple seed.

The Monospinner runs on the absolute minimum number of moving parts. Namely, one. Even a normal helicopter has a swash plate for adjustable blade pitch, and a tail rotor to keep it from spinning. Give up the idea that you want to keep it from spinning, and you can achieve controlled flight with a lot less. Well, one motor and a whole lot of math and simulation.

The Monospinner is carefully weighted so that it’s as stable as possible while spinning, but so far it’s unable to spin itself up from a standstill. In initial tests, they attached it to a pivot to help. The best part of the video (below) is when the researcher throws it, spinning, into the air and it eventually stabilizes. Very cool.

Continue reading “Your Quadcopter Has Three Propellers Too Many”

Debunking the Drone Versus Plane Hysteria

The mass media are funny in the way they deal with new technology. First it’s all “Wow, that’s Cool!”, then it’s “Ooh, that’s scary”, and finally it’s “BURN THE WITCH!”. Then a year or so later it’s part of normal life and they treat it as such. We’ve seen the same pattern repeated time and time again over the years.

The mass media tech story cycle. Our apologies to Gartner. Curve image: Jeremykemp [ CC BY-SA 3.0 ], via Wikimedia Commons
The mass media tech story cycle. Our apologies to Gartner. Curve image: Jeremykemp [ CC BY-SA 3.0 ], via Wikimedia Commons
Seasoned readers may remember silly stories in the papers claiming that the Soviets could somehow use the technology in Western 8-bit home computers for nefarious purposes, since then a myriad breathless exclusives have predicted a youth meltdown which never materialised as the inevitable result of computer gaming, and more recently groundless panics have erupted over 3D printing of gun parts. There might be a British flavour to the examples in this piece because that’s where it is being written, but it’s a universal phenomenon wherever in the world technologically clueless journalists are required to fill column inches on technical stories.

The latest piece of technology to feel the heat in this way is the multirotor. Popularly referred to as the drone, you will probably be most familiar with them as model-sized aircraft usually with four rotors. We have been fed a continuous stream of stories involving tales of near-misses between commercial aircraft and drones, and there is a subtext in the air that Something Must Be Done.

The catalyst for this piece is the recent story of a collision with a British Airways plane 1700ft over West London approaching London Heathrow. The ever-hyperbolic Daily Mail sets the tabloid tone for the story as a drone strike, while the BBC’s coverage is more measured and holds a handy list of links to near-miss reports from other recent incidents. This incident is notable in particular because a Government minister announced that it is now believed to have been caused by a plastic bag, and since there is already appropriate legislation there was little need for more. A rare piece of sense on a drone story from a politician. The multirotor community is awash with plastic bag jokes but this important twist did not seem to receive the same level of media attention as the original collision.

Are multirotors unfairly being given bad press? It certainly seems that way as the common thread among all the stories is a complete and utter lack of proof. But before we rush to their defence it’s worth taking a look at the recent stories and examining their credibility. After all if there really are a set of irresponsible owners flying into commercial aircraft then they should rightly be bought to book and it would do us no favours to defend them. So let’s examine each of those incident reports from that BBC story.

Continue reading “Debunking the Drone Versus Plane Hysteria”

Arduino Quadcopter Game Uses Serial Monitor

Every new generation of computers repeats the techniques used by the earlier generations. [Kim Salmi] created an ASCII-based quadcopter simulation game using an Arduino that displays on the Arduino serial monitor. The modern twist is the controller: an accelerometer supplements the joystick for immersive play. And of course there are flashing LEDs.

An Arduino Uno provides the processing power and drives the serial monitor. A joystick and a Hitachi H48C accelerometer are mounted on a breadboard and wired to the Uno. The tilting of the accelerometer controls the height and left-right motion of the quadcopter on the screen. The joystick sets the the ‘copter in hover mode and lowers a ‘rescue’ line. Another LED warns when the maximum height, the vertical limit of the screen, is reached. The joystick also selects one of the three quadcopters, which have different performance characteristics.

There’s a video after the break. [Kim] provides the source code so  you use it as a reference for handling the joystick and accelerometer inputs.

More proof that what is old is new.  Continue reading “Arduino Quadcopter Game Uses Serial Monitor”

A Friendly Flying Robot Pet

[luca] has always wanted a flying robot, but despite the recent popularity of quadcopters and drones [luca] has never seen a drone that is truly autonomous. Although sometimes billed as autonomous, quadcopters and fixed wing aircraft have always had someone holding a remote, had to stay in a controlled environment, or had some off-board vision system.

Computers are always getting smaller and faster, battery and motor technology is always getting better. That’s why [luca] is building a truly autonomous flying robot for the 2016 Hackaday Prize.

Since [luca] is building a coaxial copter – something that looks like a ducted fan with a few vanes at the bottom – there will be control issues. Normal helicopters use the pitch of the blades and the torque produced by the tail rotor to keep flying straight. A quadcopter uses two pairs of motors spinning in opposite directions to stay level. With just two rotors mounted on top of each other, you would think [luca]’s coaxial copter is an intractable problem. Not so; there are bizarre control systems for this type of flying machine that make it as nimble in the sky as any other helicopter.

The design of this flying robot is a bit unlike anything on the market. It looks like a flying ducted fan, with a few electronics strapped to the bottom. It’s big, but also has the minimum number of rotors, to have the highest power density possible with current technology. With a few calculations, [luca] predicted this robot will be able to hoist an IMU, GPS, ultrasonic range finder, optical flow camera, and a LIDAR module in the air for about fifty minutes. That’s a remarkably long flight time for something that hovers, and we can’t wait to see how [luca]’s build turns out.

The HackadayPrize2016 is Sponsored by:

Strandmaus, Small R/C Strandbeest

[Jeremy Cook] has been playing around with strandbeests for a while, but never had one that walked until he put a motor on it and made it R/C controlled.

These remote controlled strandbeests can’t be too heavy or they have trouble moving. He didn’t want to get too complicated, either. [Jeremy] decided his first idea – hacking a cheap R/C car – wouldn’t work. The motors and AA batteries in these cars are just too heavy. Then he realized he had a broken quadcopter lying around. The motors were all burnt out, but the battery, controller, and driver board still works. On a hunch, he hooked up beefier motors to the front and left rotor control, and found that it worked just fine.

The rest of the work was just coupling it to the mechanism. The mechanism is made of wood and metal tubes. [Jeremy] found that the strandmaus had a tendency to fall down. He figures that’s why the original strandbeests had so many legs.

For his next iteration he wants to try to make it more stable, but for now he’s just having fun seeing his little legged contraption scoot around the floor. Video after the break.

Continue reading “Strandmaus, Small R/C Strandbeest”

FAA Reauthorization Bill Includes Provisions For Hobbyists

Every year, Congress passes bills directing the funding for various departments and agencies. Sometimes, this goes swimmingly: congress recently told NASA to attempt a landing on Europa, Jupiter’s ice-covered moon. Sometimes, it doesn’t go as well. The draft of the FAA Reauthorization act of 2016 (PDF) includes provisions for drones and model airplanes amid fears of privacy-encroaching quadcopters.

As would be expected, the 2016 FAA Reauthorization act includes a number of provisions for unmanned aerial systems, a class of aircraft that ranges from a Phantom quadcopter to a Predator drone. The draft of the act includes provisions for manufacturers to prevent tampering of modification of their product, and provide the FAA with a statement of compliance, and prohibit these devices from being sold unless these conditions are met.

For a very long time, the Congress and the FAA have had special rules for model aircraft. Since 2012, the special rules for model aircraft have been simple enough: model aircraft are flown for hobby or recreational use, must operate in accordance with community-set safety guidelines, weigh less than 55 pounds, give way to manned aircraft, and not be flown within five miles of an airport. The 2016 FAA Reauthorization bill adds several updates. No model aircraft may be flown higher than 400 feet above ground level, and the operator of a model aircraft must pass a knowledge and safety test administered by the FAA. Under this draft of the FAA Reauthorization bill, you will have to pass a test to fly a quadcopter or model plane.

While this is only a draft of the 2016 FAA Reauthorization bill, there is a considerable risk flying model planes could quickly go the way of amateur radio with a Morse requirement for the license. This, of course, is due to Congress’ fears of the impact drones and model airplanes could have on safety, despite recent studies that show a 2kg drone is likely to cause injury to a human passenger once every 187 million years of operation. In other words, politicians don’t understand statistics.

Polyhedrone

[Brainsmoke] had a simple plan. Make a quadcopter with lots of addressable LEDs.

Not just a normal quadcopter with ugly festoons of LED tape though. [Brainsmoke] wanted to put his LEDs in a ball. Thus was born the polyhedrone, the idea of a flying deltoidal hexecontahedron covered as you might expect with all those addressable LEDs.

polyhedrone-PCB-kicadA Catalan solid makes a good choice for the homebrew polyhedron builder because its faces are all identical. Thus if you are making PCBs to carry LEDs, for example, you need only create a single PCB design to use on all faces. A bit of work in KiCAD, and a single face design with interlocking edges was ready. The boards were tested, a wiring layout was worked out, and the polyhedron was assembled.

But [Brainsmoke] didn’t stop there. He produced a flight case for the polyhedron, in the form of a larger polyhedron from what looks like lasercut thin ply.

Having a finished polyhedron, the next thing was to hook up a Raspberry Pi and write some software. First in Python, then in Go.

polyhedrone-light-1The results are simply stunning. If the mathematics and construction of a polyhedron were not enough to make this project worth a second look, then the gallery of images should be enough. You’ll notice that this is ostensibly a quadcopter project, yet no mention of flying has been made on this page. That’s because this is still a work in progress at Tech Inc Amsterdam, and there is more to come. But it honestly doesn’t matter if this project never moves a millimeter off the ground, as far as we are concerned [Brainsmoke] has created a superbly built thing of beauty in its own right, and we like that.

As you might expect, this is just the latest of many projects featured here that have involved addressable LEDs or quadcopters. Of note among them is this LED polyhedron that cleverly closes in all its bits, and this LED-equipped quadcopter that generates very pleasing patterns with a hi-res cross of pixels.