Lost A Lightweight Quadcopter? Here Are The Best Ways To Find It

March 6, 2021 by Donald Papp 24 Comments

Lost aircraft are harder to find when they are physically small to begin with. Not only are they harder to see, but the smaller units lack features like GPS tracking; it’s not normally possible to add it to a tiny aircraft that can’t handle much more than its own weight in the first place. As a result, little lost quads tend to be trickier to recover in general.

Fluorescent tape adds negligible weight, and will glow brightly at night under a UV light.

The good news is that [Eric Brasseur] has shared some concise tips on how to more easily locate and recover lost aircraft, especially lightweight ones. Recovering aircraft is something every aircraft hobbyist has had to deal with in one way or another, but [Eric] really has gathered an impressive list of tricks and techniques, and some of them go into some really useful additional detail. It occurs to us that a lot of these tips could apply equally well to outdoor robots, or rovers.

Even simple techniques can be refined. For example, using bright colors on an aircraft is an obvious way to increase visibility, but some colors are better choices than others. Bright orange, white, and red are good choices because they are easily detected by the human eye while still being uncommon in nature. Violet, blue, and even cyan on the other hand may seem to be good choices when viewed indoors on a workbench, but if the quad is stuck in dark bushes, those colors will no longer stand out. Another good tip is to consider also adding a few patches of fluorescent tape to the aircraft. If all else fails, return at night with a UV lamp; those patches will glow brightly, and be easily seen from tens of meters.

Some of the tips are used while the device still has power, while others don’t depend on batteries holding out. [Eric] does a great job of summing up those and many more, so take a look. They might come in handy when test flying quadcopters that are little more than an 18650 cell, motors, and a 3D-printable frame.

Demonstrating The Mars Rover Pendulum Problem With A Drone On Earth

February 25, 2021 by Danie Conradie 39 Comments

The sky crane system used on the Perseverance and Curiosity Mars rovers is a challenging control system problem that piqued [Nicholas Rehm]’s curiosity. Constrained to Earth, he decided to investigate the problem using a drone and a rock.

The setup and the tests are simple, but clearly illustrate the problem faced by NASA engineers. [Nicholas] attached a winch mechanism to the bottom of a racing-type quadcopter, and tied a mass to the end of the winch line. At first, he built a foam model of the rover, but it proved to be unstable in the wake of the quadcopter’s propellers, so he used a rock instead. The tests start with the quadcopter taking off with the rock completely retracted, which is then slowly lowered in flight until it reaches the end of the line and drops free. As soon as the rock was lowered, it started swinging like a pendulum, which only got worse as the line got longer. [Nicholas] attempted to reduce the oscillations with manual control inputs, but this only made it worse. The quadcopter is also running [Nicholas]’s own dRehmFlight flight controller that handles stabilization, but it does not account for the swinging mass.

[Nicholas] goes into detail on the dynamics of this system, which is basically a two-body pendulum. The challenges of accurately controlling a two-body pendulum are one of the main reasons the sky crane concept was shelved when first proposed in 1999. Any horizontal movement of either the drone or the rock exerts a force on the other body and will cause a pendulum motion to start, which the control system will not be able to recover from if it does not account for it. The real sky crane probably has some sort of angle sensing on the tether which can be used to compensate for any motion of the suspended rover. Continue reading “Demonstrating The Mars Rover Pendulum Problem With A Drone On Earth” →

Orphaned Gimbal Gets Second Chance To Fly

February 3, 2021 by Tom Nardi 1 Comment

A reality of flying RC aircraft is that at some point, one of your birds is going to fall in the line of duty. It could get lost in the clouds never to be seen again, or perhaps it will become suddenly reacquainted with terra firma. Whatever the reason, your overall enjoyment of the hobby depends greatly on how well you can adapt to the occasional loss.

Based on what we’ve seen so far, we’d say [Rural Flyer] has the right temperament for the job. After losing one of his quadcopters in an unfortunate FPV incident, he decided to repurpose the proprietary gimbal it left behind. If he still had the drone he could have slipped a logic analyzer in between its connection with the motorized camera to sniff out the communication protocol, but since that was no longer an option, he had to get a little creative.

Figuring out the power side of things was easy enough thanks to the silkscreen on the camera’s board, and a common 5 V battery eliminator circuit (BEC) connected to the drone’s 7.4 V battery pack got it online. A cobbled together adapter allowed him to mount it to one of his other quads, but unfortunately the angle wasn’t quite right.

[Rural Flyer] wanted the camera tilted down about 15 degrees, but since he didn’t know how to talk to it, he employed a clever brute force solution. After identifying the accelerometer board responsible for determining the camera’s position, he use a glob of hot glue to push the sensor off of the horizontal. Providing this physical offset to the sensor data caused the camera to automatically move itself to exactly where he wanted it.

Continue reading “Orphaned Gimbal Gets Second Chance To Fly” →

Mavic Mini Gets Custom Clear Case

January 19, 2021 by Lewin Day 4 Comments

Apparently, in the drone scene, sticker wraps are popular for a custom aesthetic. [Useless Mod] wanted to go a little further, however, and decided to build a full crystal enclosure for his Mavic Mini, facing some hurdles along the way. (Video, embedded below.)

The first stage of the build was disassembly, with the compact 249 gram drone requiring a deft touch to avoid damaging the delicate ribbon cables and mechanisms inside. With the drone stripped down to its bare components, a silicone mould was made of each individual piece of the case, with new parts being cast in clear epoxy. It’s not a job for the faint of heart, with many undercuts and complex features to contend with. However, [Useless Mod] managed to produce the parts and get it all back together.

An initial test flight ended poorly, when the drone entered an uncontrollable wobble due to the case not being fully assembled. However, with fresh internals and with everything properly put together, everything worked! It’s not a build we’d suggest for the inexperienced, as the moulds required are complex and the electronics quite fragile. The final result is a good one though, and it even weighs 10 grams less than the original casing!

For those in the US, the world of drones is set to change drastically in short order.

Continue reading “Mavic Mini Gets Custom Clear Case” →

Hackaday Links: January 3, 2021

January 3, 2021 by Dan Maloney 28 Comments

Last week we featured a story on the new rules regarding drone identification going into effect in the US. If you missed the article, the short story is that almost all unmanned aircraft will soon need to transmit their position, altitude, speed, and serial number, as well as the position of its operator, likely via WiFi or Bluetooth. The FAA’s rule change isn’t sitting well with Wing, the drone-based delivery subsidiary of megacorporation Alphabet. In their view, local broadcast of flight particulars would be an invasion of privacy, since observers snooping in on Remote ID traffic could, say, infer that a drone going between a pharmacy and a neighbor’s home might mean that someone is sick. They have a point, but how a Google company managed to cut through the thick clouds of irony to complain about privacy concerns and the rise of the surveillance state is mind boggling.

Speaking of regulatory burdens, it appears that getting an amateur radio license is no longer quite the deal that it once was. The Federal Communications Commission has adopted a $35 fee for new amateur radio licenses, license renewals, and changes to existing licenses, like vanity call signs. While $35 isn’t cheap, it’s not the end of the world, and it’s better than the $50 fee that the FCC was originally proposing. Still, it seems a bit steep for something that’s largely automated. In any case, it looks like we’re still good to go with our “$50 Ham” series.

Staying on the topic of amateur radio for a minute, it looks like there will be a new digital mode to explore soon. The change will come when version 2.4.0 of WSJT-X, the program that forms the heart of digital modes like WSPR and FT8, is released. The newcomer is called Q65, and it’s basically a follow-on to the current QRA64 weak-signal mode. Q65 is optimized for weak, rapidly fading signals in the VHF bands and higher, so it’s likely to prove popular with Earth-Moon-Earth fans and those who like to do things like bounce their signals off of meteor trails. We’d think Q65 should enable airliner-bounce too. We’ll be keen to give it a try whenever it comes out.

Look, we know it’s hard to get used to writing the correct year once a new one rolls around, and that time has taken on a relative feeling in these pandemic times. But we’re pretty sure it isn’t April yet, which is the most reasonable explanation for an ad purporting the unholy coupling of a gaming PC and mass-market fried foods. We strongly suspect this is just a marketing stunt between Cooler Master and Yum! Brands, but taken at face value, the KFConsole — it’s not a gaming console, it’s at best a pre-built gaming PC — is supposed to use excess heat to keep your DoorDashed order of KFC warm while you play. In a year full of incredibly stupid things, this one is clearly in the top five.

And finally, it looks like we can all breathe a sigh of relief that our airline pilots, or at least a subset of them, aren’t seeing things. There has been a steady stream of reports from pilots flying in and out of Los Angeles lately of a person in a jetpack buzzing around. Well, someone finally captured video of the daredevil, and even though it’s shaky and unclear — as are seemingly all videos of cryptids — it sure seems to be a human-sized biped flying around in a standing position. The video description says this was shot by a flight instructor at 3,000 feet (914 meters) near Palos Verdes with Catalina Island in the background. That’s about 20 miles (32 km) from the mainland, so whatever this person is flying has amazing range. And, the pilot has incredible faith in the equipment — that’s a long way to fall in something with the same glide ratio as a brick.

Transforming Drone Can Be A Square Or A Dragon

January 1, 2021 by Danie Conradie 8 Comments

When flying drones in and around structures, the size of the drone is generally limited by the openings you want to fit through. Researchers at the University of Tokyo got around this problem by using an articulating structure for the drone frame, allowing the drone to transform from a large square to a narrow, elongated form to fit through smaller gaps.

The drone is called DRAGON, which is somehow an acronym for the tongue twisting description “Dual-Rotor Embedded Multilink Robot with the Ability of Multi-Degree-of-Freedom Aerial Transformation“. The drone consists of four segments, with a 2-DOF actuated joint between each segment. A pair of ducted fan motors are attached to the middle of each segment with a 2-DOF gimbal that allows it to direct thrust in any direction relative to the segment. For normal flight the segments would be arranged in the square shape, with minimal movement between the segments. When a small gap is encountered, as demonstrated in the video after the break, the segments rearrange into a dragon-like shape, that can pass through a gap in any plane.

Each segment has its own power source and controller, and the control software required to make everything work together is rather complex. The full research paper is unfortunately behind a paywall. The small diameter of the propellers, and all the added components would be a severe limiting factor in terms of lifting capacity and flight time, but the concept is to definitely interesting.

The idea of shape shifting robots has been around for a while, and can become even more interesting when the different segment can detach and reattach themselves to become modular robots. The 2016 Hackaday Grand Prize winner DTTO is a perfect example of this, although it did lack the ability to fly. Continue reading “Transforming Drone Can Be A Square Or A Dragon” →

Federal Aviation Administration Announces Major Drone Rule Changes

December 29, 2020 by Dan Maloney 61 Comments

If new rules from the FAA regarding unmanned aircraft operations in the US are any indication, drones are becoming less of a niche hobby and more integrated into everyday life. Of course, the devil is in the details, and what the Federal Aviation Administration appears to give with one hand, it takes away with the other.

The rule changes, announced on December 28, are billed as “advanc[ing] safety and innovation” of the drone industry in the United States. The exciting part, and the aspect that garnered the most attention with headline writers, is the relaxation of rules against night operation and operating above people and moving vehicles. Since 2016, it has been against FAA regulations to operate drones less than 55 pounds (25 kg) at night or over people without a waiver. This rule can be seen as stifling innovations in drone delivery, since any useful delivery service will likely need to overfly populated areas and roadways and probably do so at night. The new rules allow these operations without a waiver for four categories of drones, classified by how much damage they would do if they were to lose control and hit someone. The rules also define the inspection and certification regimes for both aircraft and pilot, as well as stipulating that operators have to have their certificate and ID on their person while flying.

While this seems like great news, the flip side of the coin is perhaps less shiny. The rule changes also impose the requirement for “Remote ID” (PDF link), which is said to be “a major step toward full integration of drones into the national airspace system.” Certain drones will be required to carry a system that transmits identification messages directly from the aircraft, including such data as serial number, location and speed of the drone, as well as the location of the operator. The rules speculate that this would likely be done over WiFi or Bluetooth, and would need to be receivable with personal wireless devices. The exact technical implementation of these rules is left as an exercise to manufacturers, who have 30 months from the time the rules go into effect in January to design systems, submit them for certification, and get them built into their aircraft. Drone operators have an additional year to actually start using the Remote ID drones.

For the drone community, these rule changes seem like a mixed bag. To be fair, it’s not exactly unexpected that drones would be radio tagged like this, and the lead time allowed by the FAA for compliance on Remote ID seems generous. The ability to operate in riskier environments will no doubt be welcomed by commercial drone operators. So who knows — maybe the rules will do what they say they will, and this will stimulate a little innovation in the industry. If so, it could make this whole thing a net positive.