Micro Quadcopter Designed In OpenSCAD

April 2, 2021 by 20 Comments

Quadcopters are fantastical things, and now come in a huge variety of flavours, from lithe featherweight racers to industrial-grade filming rigs worth tens of thousands of dollars. The Beatle-1 from [masterdezign] comes in at the smaller scale, and its body was created entirely in code.

To create the Beatle-1, [masterdezign] used OpenSCAD, a 3D modelling program that uses code rather than visual tools for producing geometry. Thus, with a series of Boolean operations, extrusions and rotations, a basic lightweight quadcopter frame is created in a handful of lines of text. Then, it’s just a simple job of 3D printing the parts, wiring up four Olimex F1607 motors and hooking up a flight controller and the little drone is ready for takeoff.

The Beatle-1 serves as not only a fun flying toy but also a great example of applying OpenSCAD modelling techniques to real-world applications. Parts are available on Thingiverse for those wishing to roll their own. 3D printed drone frames are popular, and we’ve seen a few around these parts before. Video after the break.

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Open Source Motion Controller For DIY Drones

March 24, 2021 by 7 Comments

DJI recently introduced a slick motion controller that eschews the traditional dual-stick transmitter and allows you to fly their new “FPV Drone” with just one hand. The fact that it looks like it could double as the control stick for an X-Wing is just an added bonus. Unfortunately, that single model is the only thing the $199 USD controller is currently compatible with. Unwilling to get locked into the DJI ecosystem, [Paweł Spychalski] has developed an open source work-alike motion controller that brings gesture flying to home-built quadcopters and airplanes.

Now to be clear, you’ll still need a traditional transmitter to use this device. Rather than trying to reinvent the wheel, [Paweł] decided to implement his motion controller as an add-on for OpenTX hardware like the RadioMaster TX16S. It simply plugs into the trainer port on the back of the transmitter and acts as a secondary input. This greatly simplifies the design, as it essentially just needs to read angle data from its MPU-6050 gyro/accelerometer and forward it along to OpenTX over the serial port. Plus the fact that it’s connected to the trainer port means you can disable it and return to traditional controls in an instant if anything goes wrong.

Outside of the motion sensing gear, the ESP32-powered peripheral also has a thumb stick and a pair of push buttons nestled into its 3D printed frame. An OLED display provides some user feedback, and a holder for a 18650 cell is mounted to the back side as the controller will need its own power source when [Paweł] gets around to making its connection to the transmitter wireless.

In the video below, [Paweł] takes the motion controller for a test flight and comes away largely satisfied with the results. Some tweaks are in the works as you might expect for a first attempt, but nothing that would prevent you from building your own version today and experiencing what might be the next evolution of RC flying.

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Resilient AI Drone Packs It All In Under 250 Grams

March 15, 2021 by 14 Comments

When it was first announced that limits would be placed on recreational RC aircraft heavier than 250 grams, many assumed the new rules meant an end to home built quadcopters. But manufacturers rose to the challenge, and started developing incredibly small and lightweight versions of their hardware. Today, building and flying ultra-lightweight quadcopters with first person view (FPV) cameras has become a dedicated hobby onto itself.

But as impressive as those featherweight flyers might be, the CogniFly Project is really pushing what we thought was possible in this weight class. Designed as a platform for experimenting with artificially intelligent drones, this open source quadcopter is packing a Raspberry Pi Zero and Google’s AIY Vision Kit so it can perform computationally complex tasks such as image recognition while airborne. In case any of those experiments take an unexpected turn, it’s also been enclosed in a unique flexible frame that makes it exceptionally resilient to crash damage. As you can see in the video after the break, even after flying directly into a wall, the CogniFly can continue on its way as if nothing ever happened.

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

March 6, 2021 by 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.

Orphaned Gimbal Gets Second Chance To Fly

February 3, 2021 by 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.

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Controlling A Quadcopter With One Dead Motor

January 28, 2021 by 17 Comments

Quadcopters have incredible flying abilities, but if one loses just a single motor, it drops like a rock. Researchers from the University of Zurich’s Robotics and Perception Group have proven that this does not need to be the case by keeping a quadcopter flying with only three motors.

A quadcopter usually has enough thrust to stay aloft with only three motors, but it will spin uncontrollably in the yaw axis. It is impossible to stop a quadcopter from spinning, so the focus for researchers was on keeping the drone controllable while it’s spinning. To achieve this, accurate position and motion estimation is required, so they attached a pair of cameras to the bottom of the craft for visual-inertial odometry (VIO). One is a normal optical camera, while the other is an event camera, which has pixels that can independently respond to changes in light as they occur. This means that it has better low light performance and does not suffer from motion blur.

The feeds from the cameras are analyzed in real-time by an onboard Nvidia Jetson TX2 for state estimation, which is then used with an optical range sensor and onboard IMU to maintain controlled flight, as demonstrated in the video after the break. The research paper is free to read, and all the code is available on GitHub.

New developments in drone control schemes are always fascinating, like this hexacopter with an innovative motor layout to achieve six degrees of freedom, or a conventional helicopter with a virtual swash plate.
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LEDs From Dubai: The Royal Lights You Can’t Buy

January 17, 2021 by 103 Comments

[Clive] had an interesting video about LED lights from Philips. You can’t buy them unless you live in Dubai. Apparently inspired by the ruler of Dubai, Sheikh Mohammad Bin Rashid Al Maktoum, who wanted more efficient and longer-lasting bulbs. The secret? A normal LED bulb uses an LED “filament” at 1 watt each. The Dubai bulbs run at about a fourth of that which means they need more LEDs to get the same amount of light, but they should last longer and operate more efficiently.

After exploring the brightness and color of different lamps, [Clive] tears one up and finds some surprises inside. The LEDs get over 200V each and the driver circuit has a lot of pairs of components, possibly to keep the size small for the high voltages involved, although it could be to improve reliability, [Clive] wasn’t sure.

By reducing the power, [Clive] was able to count that each LED strip contains 21 LEDs. He also notes some of the oddities in construction that appear to be for reliability and ease of manufacturing. We aren’t sure how that compares to the construction of conventional bulbs. The circuit includes a bridge rectifier and a linear current regulator using a MOSFET.

The bulbs cost a bit more, but if you factor in the probable long life, their total cost over time should be reasonable. Overall, it is interesting that a nice design came from what amounts to government regulation. Of course, there is a price: in exchange for the development of the bulbs, Philips has the exclusive right to make and sell the bulbs for the next several years. They expect to sell 10 million lamps by the end of 2021, although they are only available, currently, in Dubai.

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