3D Printed Quadcopter Props

Here’s something that isn’t quite a hack; he’s just using a 3D printer as a 3D printer. It is extremely interesting, though. Over on Hackaday.io [Anton] is creating 3D printable propellers for quadcopters and RC planes. Conventional wisdom says that propellers require exceedingly exacting tolerances, but [Anton] is making it work with the right 3D file and some creative post-processing treatment of his prints.

These 3D printed props are a remix of an earlier project on Thingiverse. In [Anton]’s testing, he didn’t get the expected lift from these original props, so a few small modifications were required. The props fit on his 3D printer bed along their long edge allowing for ease of slicing and removal of support material. For post-processing, [Anton] is using acetone vapor smoothing on his ABS printed design. They come out with a nice glossy sheen, and should be reasonably more aerodynamic than a prop with visible layer lines.

Although [Anton]’s prop is basically a replica of a normal, off-the-shelf quadcopter prop, 3D printing unique, custom props does open up a lot of room for innovation. The most efficient propeller you’ll ever find is actually a single-bladed propeller, and with a lot of experimentation, it’s possible anyone with a well-designed 3D printer could make turn out their own single-blade prop.

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You Might Want To Buy A Quadcopter Now

NBC News has reported the US Government may implement regulations in the coming days that would require anyone who buys an unmanned aircraft system to register that device with the US Department of Transportation.

The most simplistic interpretation of this news is that anyone with a DJI Phantom or a model aircraft made out of Dollar Tree foam board would be required to license their toys. This may not be the case; the FAA – an agency of the US DoT – differentiates between unmanned aircraft systems and model aircraft.

This will most likely be the key thing to watch out for in any coming regulation. The FAA defines model aircraft as, “an unmanned aircraft that is capable of sustained flight in the atmosphere; flown within visual line of sight of the person operating the aircraft; and flown for hobby or recreational purposes.” Additionally, the FAA may not make any regulations for model aircraft. While this means planes and quads flown without FPV equipment may be left out of this regulation, anything flown ‘through a camera’ would be subject to regulation.

Show a Quadcopter Flight on Google Earth for Under Ten Bucks

[Joop Brokking] wanted to know where his quadcopter was and had been. He thought about Google Earth, but assumed it would be difficult to get the GPS data and integrate it with Google’s imagery. But he discovered it was easier than he thought. He wound up spending around $10, although if his ‘copter didn’t already have GPS, it would have been more.

Hardware-wise, [Joop] made a pretty straightforward data logger using a small Arduino (a Pro Mini) and an SD Card (along with an SD breakout board). With this setup, NMEA data from the GPS comes in the Arduino’s serial port and winds up on the SD Card.

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Hijacking Quadcopters with a MAVLink Exploit

Not many people would like a quadcopter with an HD camera hovering above their property, and until now there’s no technical resource to tell drone pilots to buzz off. That would require actually talking to a person. Horrors. Why be reasonable when you can use a Raspberry Pi to hijack a drone? It’s the only reasonable thing to do, really.

The folks at shellIntel have been messing around with quads for a while, and have recently stumbled upon a vulnerability in the Pixhawk flight controller and every other quadcopter that uses the MAVLink protocol. This includes the Parrot AR.drone, ArduPilot, PX4FMU, pxIMU, SmartAP, MatrixPilot, Armazila 10dM3UOP88, Hexo+, TauLabs and AutoQuad. Right now, the only requirement to make a drone fall out of the sky is a simple radio module and a computer. A Raspberry Pi was used in shellIntel’s demo.

The exploit is a consequence of the MAVLink sending the channel or NetID used to send commands from the transmitter to the quadcopter in each radio frame. This NetID number is used so multiple transmitters don’t interfere with each other; if two transmitters use the same NetID, there will be a conflict and two very confused pilots. Unfortunately, this also means anyone with a MAVLink radio using the same NetID can disarm a quadcopter remotely, and anyone with a MAVLink radio can tell a quad to turn off, or even emulate the DJI Phantom’s ‘Return to China’ function.

The only required hardware for this exploit is a $100 radio and three lines of code. It is certainly possible to build a Raspberry Pi-based box that would shut down any Pixhawk-equipped quadcopter within radio range, although the folks at shellIntel didn’t go that far just yet. Now it’s just a proof of concept to demonstrate that there’s always a technical solution to your privacy concerns. Video below.

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No, Mounting A Gun To A Quadcopter (Probably) Isn’t Illegal

Earlier this month, [Austin Haghwout] posted a video on YouTube of a remote controlled quadcopter armed with a semiautomatic handgun. While there are no details of this build, it’s safe to say any reasonably sized quadcopter could be armed in such a manner; just strap a pistol to the frame, add a servo, and connect the servo to the RC receiver. We don’t think this is the first time it’s been done, but has garnered the most attention.

There is nothing novel about mounting a handgun to a quadcopter. Anyone with any experience with RC flying could replicate this build, and the only interesting part of watching a video of a quad firing a gun is seeing how the flight controller reacts to the recoil. However, in the pursuit of the exploitation of a fear of technology, this video has gone viral.

The Verge calls it, ‘totally illegal’, while The Christian Science Monitor asks how it is legal. Wired posits it is, ‘most likely illegal,’ while CNET suggests, ‘surely this isn’t legal.’ In a rare break from reality, YouTube commentors have demonstrated a larger vocabulary than normal, calling the build, ‘felonious.’

With so many calling this build illegal, there should be someone who could point out the laws or regulation [Austin Haghwout] is violating. This information is surprisingly absent. In a Newsweek post, a representative from the Bureau of Alcohol, Tobacco, Firearms, and Explosives is quoted as saying:

“ATF has reviewed the video with local law enforcement and other federal agencies. It does not appear that the device violates any existing firearms regulations…”

The Associated Press reports no state laws were broken by [Austin]. With the BAFTE and Connecticut State Police both signing off on this build, the issue of jurisdiction becomes more pronounced. How, exactly, is a gun mounted on a quad illegal?

The answer, as with all things involving quadcopters, comes from the FAA. We could find no regulations explicitly banning handguns on remote controlled quadcopters, but of all stories and posts on [Austin]’s handiwork, this is the closest anyone has come to providing the framework for calling this build illegal:

No pilot in command of a civil aircraft may allow any object to be dropped from that aircraft in flight that creates a hazard to persons or property. However, this section does not prohibit the dropping of any object if reasonable precautions are taken to avoid injury or damage to persons or property.

-FAR Part 91 Sec. 91.15

That’s it. The closest anyone has come to providing a reason why a semiauto quadcopter is illegal: because the cartridge (and bullet), are ‘dropped’ from a quad. The Feds charging [Austin] with “dropping” a bullet from a quadcopter is like taking down [Al Capone] for Income Tax Evasion. The difference being that [Al] was a notorious criminal who had obviously harmed a large swath of people and [Austin] doesn’t seem to be harming anyone.

Although [Austin]’s video of a gun toting quad is only fourteen seconds long, a few reasonable assumptions can be made about his small experiment in flying firepower. The video shows the quad hovering a few feet above the ground. This is surely allowed by the recently published safety guidelines for sUAS users. The gun itself appears to be firing into an offscreen hillside – a sensible precaution. If the only justification for the FAA’s investigation of [Austin]’s video is FAR 91.15, he’s on easy street.

“Drones” Endanger Airborne Wildfire Fighting

usdaThere is no denying that personal drones are in the public eye these days. Unfortunately they tend to receive more negative press than positive. This past weekend, there were news reports of a wildfire in California. Efforts to fight the fire were hampered when no less than five drones were spotted flying in the area. Some reports even stated that two of the drones followed the firefighting aircraft as they returned to local airports. This is the fourth time this month firefighting planes have been grounded due to unmanned aircraft in the area. It’s not a new problem either, I’ve subscribed to a google alert on the word “Drone” for over a year now, and it is rare for a week to go by without a hobby drone flying somewhere they shouldn’t.

The waters are muddied by the fact that mass media loves a good drone story. Any pilotless vehicle is now a drone, much to the chagrin of radio control enthusiasts who were flying before the Wright brothers. In this case there were two fields relatively close to the action – Victor Valley R/C Park, about 10 miles away, and the Cajun Pass slope flying field, which overlooks the section of I-15 that burned. There are claims on the various R/C forums and subreddits that it may have been members from either of those groups who were mistaken as drones in the flight path. Realistically though, Victor Valley is too far away. Furthermore, anyone at the Cajun pass flying site would have been fearing for their own safety. Access requires a drive through 3 miles of dirt road just to reach the site. Not a place you’d want to be trapped by a wildfire for sure. Who or whatever was flying that day is apparently lying low for the moment – but the problem persists.

Rules and Regulations

In the USA, the FAA rules are (finally) relatively clear for recreational drone operations. The layman version can be found on the knowbeforeyoufly.org website, which was put together by the Academy of Model Aeronautics (AMA), The Association for Unmanned Vehicle Systems International (AUVSI), and other groups in partnership with the FAA.

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Send In The Drones: Putting Wheels And Wings On The Internet Of Things

Imagine you’re a farmer trying to grow a crop under drought conditions. Up-to-the-minute data on soil moisture can help you to decide where and when to irrigate, which directly affects your crop yield and your bottom line. More sensors would mean more data and a better spatial picture of conditions, but the cost of wired soil sensors would be crippling. Wireless sensors that tap into GSM or some sort of mesh network would be better, but each sensor would still need power, and maintenance costs would quickly mount. But what if you could deploy a vast number of cheap RFID-linked sensors in your fields? And what if an autonomous vehicle could be tasked with the job of polling the sensors and reporting the data? That’s one scenario imagined in a recent scholarly paper about a mobile Internet of Things (PDF link).


In the paper, authors [Jennifer Wang], [Erik Schluntz], [Brian Otis], and [Travis Deyle] put a commercially available quadcopter and RC car to the hack. Both platforms were fitted with telemetry radios, GPS, and an off-the-shelf RFID tag reader and antenna. For their sensor array, they selected passive UHF RFID tags coupled to a number of different sensors, including a resistance sensor used to measure soil moisture. A ground-control system was developed that allowed both the quad and the car to maneuver to waypoints under GPS guidance to poll sensors and report back.

Beyond agriculture, the possibilities for an IoT based on cheap sensors and autonomous vehicles to poll them are limitless. The authors rightly point out the challenges of building out a commercial system based on these principles, but by starting with COTS components and striving to keep installed costs to a minimum, we think they’ve done a great proof of concept here.