Flies Like A Quadcopter, But This Drone Design Has Only One Propeller

November 2, 2020 by Danie Conradie 35 Comments

When mentioning drones, most people automatically think of fixed-wing designs like the military Reaper UAV or of small quadcopters. However, thanks in large part to modern electronics, motors, and open-source control systems, it is possible to build them in a variety of shapes and sizes. [Benjamin Prescher] is working on the second version of his single rotor Ball-Drone, which uses four servo-actuated fins for control.

The first version of the ball drone flew but was barely controllable and had a tendency to tip over. After a bit of research, he found that he had fallen victim to the drone pendulum fallacy by mounting the heavy components below the propeller and control fins. Initially, he also used conventional fin control that caused the servos to jitter due to high torque loading. By changing to grid fins, the actuation torque was reduced, eliminating the servo jitter.

Mk2 corrected the pendulum problem by moving most of the components to the top of the drone. The 3D printed frame (available on Thingiverse) was also dramatically changed and simplified to reduce weight. Although [Benjamin] designed a custom flight controller with custom control software, the latest parts list contains an off-the-shelf flight controller. He mentions that he had started working with Betaflight. The most complex part of a drone is not the mechanics or even the electronics, but the control software. Thanks to open source projects like Betaflight and Ardupilot, you don’t need to write control software from scratch to get something in the air.

The ball drone seems well suited to an indoor environment, but we’re not sure if it has any real advantages over a quadcopter with ducted propellers. Servos are cheaper than motors and ESCs, so there might be a small cost saving. Drop your thoughts on the advantages/disadvantages in the comments below. Continue reading “Flies Like A Quadcopter, But This Drone Design Has Only One Propeller” →

Fuel Cell Drone Aims For Extended Flight Times

October 31, 2020 by Lewin Day 15 Comments

The RC world was changed forever by the development of the lithium-polymer battery. No longer did models have to rely on expensive, complicated combustion engines for good performance. However, batteries still lack the energy density of other fuels, and so flying times can be limited. Aiming to build a drone with impressively long endurance, [Игорь Негода] instead turned to hydrogen power.

The team fitted a power meter to the plane, aiming a camera at it to measure power draw during flight.

With a wingspan of five meters, and similar length, the build is necessarily large in order to carry the hydrogen tank and fuel cell that will eventually propel the plane, which uses a conventional brushless motor for propulsion. Weighing in at 6 kilograms, plenty of wing is needed to carry the heavy components aloft. Capable of putting out a maximum of 200W for many hours at a time, the team plans to use a booster battery to supply extra power for short bursts, such as during takeoff. Thus far, the plane has flown successfully on battery power, with work ongoing to solve handling issues and determine whether the platform can successfully fly on such low power.

We’re eager to see how the project develops, particularly in regards to loiter time. We can imagine having a few pilots on hand may be necessary with such a long flight time planned — other drones of similar design have already surpassed the 60-minute mark. Video after the break.

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Scratching That Itch

October 31, 2020 by Elliot Williams 11 Comments

I did something silly. I bought a lot of ten “broken” cheesy indoor quadcopters on eBay — to hopefully cobble one working one together and to amuse my son. At this point, I’ve got eight working. The bad news is that they all come with dirt-cheap transmitters that aren’t really conducive to flying at all. They’d be a lot more fun if they could be controlled with a real remote. Enter the hackers.

Most all of the cheap quads are based on one of a handful of radio chipsets, although they use different protocols. An enterprising hacker could conceivably just bundle together this handful of radio modules, and the rest would be a simple matter of software. That’s exactly what Pascal Langer’s DIY Multiprotocol TX and supporting firmware does. This hobby project was so successful that compatible hardware is manufactured by more than a few Chinese companies, and non-geeks have them installed in their radios. The module lets you control virtually anything that uses 2.4 GHz. Of course, I’ve got one of them.

I opened up the cheesy drone’s transmitter, found that it used a popular chipset, and worked through all the different supported protocols that used it. No dice. But the radio module did have nicely labeled SPI lines, so I reached out to Pascal. A couple of Sigrok sessions later, he’d figured out that it was trying to bind on a different channel, I’d recompiled the firmware, and was playing with the drone’s other functions.

I just love a good SPI-sniffing session. sigrok-cli -d fx2lafw -c samplerate=4000000 -P spi:clk=D0:mosi=D1:cs=D2 -A spi="mosi transfer" --continuous | grep A0 | uniq reads the SPI lines, decodes the packets, filters out the commands, and removes duplicates, in real-time. All that’s left to do is wiggle the sticks, mash buttons, and take good notes.

None of this was hard, and certainly none of it was expensive. I got my drones under the control of my fancy-schmancy remote, and have a good foothold into controlling them algorithmically later on thanks to everyone’s previous work on reverse engineering these protocols. Support for DF Drone’s SkyTumbler will be included in the next DIY Multiprotocol TX release, and I spent about four or five pleasant hours on this project. Maybe only a handful of people will stumble on this particular protocol — or maybe it will just be me. I did it mostly just to scratch my own particular itch.

But that’s one way open source works, thrives, and grows. Here’s to you all out there, from the Deviation team, who did a lot of the early drone protocol reverse engineering, to Pascal for the DIY Module, to the Sigrok folks who made the tools accessible for me to piggyback on everyone’s previous work. Keep on hacking!

You Don’t Need A Weatherman To Know Which Way The Drone Blows

September 7, 2020 by Al Williams 11 Comments

“How’s the weather?” is a common enough question down here on the ground, but it’s even more important to pilots. Even if they might not physically be in the cockpit of the craft they are flying. [Justin Parsons] explains how weather affects drone flights and how having API access to micro weather data can help ensure safe operations.

As drone capability and flight time increase, the missions they will fly are getting more and more complex. [Justin] uses a service called ClimaCell which has real-time, forecast, and historical weather data available across the globe. The service isn’t totally free, but if you make fewer than 1,000 calls a day you might be able to use a developer account which doesn’t cost anything.

According to [Justin], weather data can help with pre-flight planning, in-flight operations, and post-flight analysis. The value of accurate forecasting is indisputable. However, a drone or its ground controller could certainly understand real-time weather in a variety of ways and record it for later use, so the other two use cases maybe a little less valuable.

While on the subject, it seems to us that accurate forecasting could be important for other kinds of projects. Will you have enough sun to catch a charge on your robot lawnmower tomorrow? If your beach kiosk is expecting rain, it could deploy an umbrella or close some doors and shutdown for a bit.

If you insist on using a free service, the ClimaCell blog actually lists their top 8 APIs. Naturally, their service is number one, but they do have an assessment of others that seems fair enough. Nearly all of these will have some cost if you use it enough, but many of them are pretty reasonable unless you’re making a huge number of calls.

How would you use accurate micro weather data? Let us know in the comments. Then again, sometimes you want to know the weather right from your couch. Or maybe you’d like your umbrella to tell you how long the storm is going to last.

“A Guy In A Jet Pack” Reported Flying Next To Aircraft Near LAX

September 1, 2020 by Mike Szczys 63 Comments

In case you needed more confirmation that we’re living in the future, a flight on approach to Los Angeles International Airport on Sunday night reported “a guy in a jet pack” flying within about 300 yards of them. A second pilot confirmed the sighting. It’s worth watching the video after the break just to hear the recordings of the conversation between air traffic control and the pilots.

The sighting was reported at about 3,000 feet which is an incredible height for any of the jet packs powerful enough to carry humans we’ve seen. The current state of the art limits jet pack tech to very short flight times and it’s hard to image doing anything more than getting to that altitude and back to the ground safely. Without further evidence it’s impossible to say, which has been an ongoing problem with sightings of unidentified flying objects near airports.

While superheros (or idiots pretending to be superheros) flying at altitude over the skies of LA sounds far fetched, the RC super hero hack we saw nine years ago now comes to mind. At 300 yards, that human-shaped drone might pass for an actual person rather than a dummy. This is of course pure speculation and we don’t want to give the responsible members for the RC aircraft community a bad name. It could have just as easily been trash, balloons, aliens, or Mothra. Or perhaps the pilot was correct and it was “some guy” flying past at 3,000 feet. That’s not impossible.

We anxiously await the results of the FAA’s investigation on this one.

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Drone Buoy Drifts Along The Gulf Stream For Citizen Science

August 13, 2020 by Dan Maloney 26 Comments

It may be named after the most famous volleyball in history, but “Wilson” isn’t just a great conversationalist. [Hayden Brophy] built the free-drifting satellite buoy to see if useful science can be done with off-the-shelf hardware and on a shoestring budget. And from the look of the data so far, Wilson is doing pretty well.

Wilson belongs to a class of autonomous vessels known as drifters, designed to float along passively in the currents of the world’s ocean. The hull of [Hayden]’s drifter is a small Pelican watertight case, which contains all the electronics: Arduino Pro Trinket, GPS receiver, a satellite modem, and a charger for the LiPo battery. The lid of the case is dominated by a 9 W solar panel, plus the needed antennas for GPS and the Iridium uplink and a couple of sensors, like a hygrometer and a thermometer. To keep Wilson bobbing along with his solar panel up, there’s a keel mounted to the bottom of the case, weighted with chains and rocks, and containing a temperature sensor for the water.

Wilson is programmed to wake up every 12 hours and uplink position and environmental data as he drifts along. The drifter was launched into the heart of the Gulf Stream on August 8, about 15 nautical miles off Marathon Key in Florida, by [Captain Jim] and the very happy crew of the “Raw Deal”. As of this writing, the tracking data shows that Wilson is just off the coast of Miami, 113 nautical miles from launch, and drifting along at a stately pace of 2.5 knots. Where the buoy ends up is anyone’s guess, but we’ve seen similar buoys make it all the way across the Atlantic, so here’s hoping that hurricane season is kind to Wilson.

We think this is great, and congratulations to [Hayden] for organizing a useful and interesting project.

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True Craftsmanship: Pneumatic Powered Drone Wasn’t Made To Fly

August 10, 2020 by Danie Conradie 16 Comments

From time to time it’s good to be reminded that mechanical engineering can also be art. [José Manuel Hermo Barreiro], also known as [Patelo], is a retired naval mechanic with a love for scale model engines. Using only basic tools and a lathe, he has built a non-flying hexacopter display model, each propeller turned by a tiny single cylinder motor that runs on compressed air. From the tiny components of the valve systems, the brass framed acrylic windows into the crankcases, and the persistence of vision disc on the exhaust, the attention to detail is breathtaking.

One of the six hand crafted pneumatic motors

[Patelo] started the project on paper, and created a set of detailed hand-drawn blueprints to work from. Sadly a large part of the build took place during lockdown, and was not filmed, but we still get to see some work on a crankcase, connecting rod, camshaft, propellers, flywheel, and exhaust tubes. It is very clear that [Patelo] knows his way around his lathe very well, and is very creative with custom tools and jigs. The beautiful machine took approximately 1,560 hours to build, consists of 265 individually made parts held together with 362 screws.

We previously featured tiny V-12 engine that [Patelo] built around 2012. At that time he was 72 years of age, which means he should be around 80 now. We can only hope to come to emulate him one day, and that we get to see more of what comes out of his workshop. Hats off to you, sir.