Clever Control Loop Makes This Spinning Drone Fault-Tolerant

November 9, 2022 by 18 Comments

Most multi-rotor aircraft are about as aerodynamic as a brick. Unless all its motors are turning and the control electronics are doing their thing, most UAVs are quickly destined to become UGVs, and generally in spectacular fashion. But by switching up things a bit, it’s possible to make a multi-rotor drone that keeps on flying even without two-thirds of its motors running.

We’ve been keeping a close eye on [Nick Rehm]’s cool spinning drone project, which basically eschews a rigid airframe for a set of three airfoils joined to a central hub. The collective pitch of the blades can be controlled via a servo in the hub, and the whole thing can be made to rotate and provide lift thanks to the thrust of tip-mounted motors and props. We’ve seen [Nick] manage to get this contraption airborne, and hovering is pretty straightforward. The video below covers the next step: getting pitch, roll, and yaw control over the spinning blades of doom.

The problem isn’t trivial. First off, [Nick] had to decide what the front of a spinning aircraft even means. Through the clever uses of LED strips mounted to the airfoils and some POV magic, he was able to visually indicate a reference axis. From there he was able to come up with a scheme to vary the power to each motor as it moves relative to the reference axis, modulating it in either a sine or cosine function to achieve roll and pitch control. This basically imitates the cyclic pitch control of a classic helicopter — a sort of virtual swashplate.

The results of all this are impressive, if a bit terrifying. [Nick] clearly has control of the aircraft even though it’s spinning at 250 RPM, but even cooler is the bit where he kills first one then two motors. It struggles, but it’s still controllable enough for a bumpy but safe landing.

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Bare-Metal STM32: Setting Up And Using SPI

October 24, 2022 by 52 Comments

The Serial Peripheral Interface (SPI) interface was initially standardized by Motorola in 1979 for short-distance communication in embedded systems. In its most common four-wire configuration, full-duplex data transfer is possible on the two data (MOSI, MISO) lines with data rates well exceeding 10 Mb/s. This makes SPI suitable for high-bandwidth, full-duplex applications like SD storage cards and large resolution, high-refresh displays.

STM32 devices come with a variable number of SPI peripherals, two in the F042 at 18 Mb/s and five in the F411. Across the STM32 families, the SPI peripheral is relatively similar, with fairly minor differences in the register layout. In this article we’ll look at configuring an SPI peripheral in master mode.

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Organizational Inspiration From The Discount Tool Company

October 15, 2022 by 13 Comments

When in need of any tool to get a job done quickly, or only for a small number of times, it’s great to have a local “discount tool” company locally for some working, yet often low-quality solution to whatever problem might arise. While there are some gems, most of these tools won’t last through heavy, sustained use like their more expensive counterparts will. On the other hand, there are other things to be had at these discount shops, such as inspiration for tackling a storage problem.

This particular storage system comes from Harbor Freight, and uses a set linked crosshairs, the center of which is hollowed out. A set of movable compartments sits on top with feet that can interlock inside the crosshairs. This allows much more efficient use of space within the toolboxes, but [Alan] wanted it to be useful for more that that. He designed and implemented the Storage Case Base Template (SCBT) which allows for a container of any size to be fitted with a similar crosshair network.

With this non-proprietary system implemented and printed, the original goal of reducing the clutter in [Alan]’s workspace was accomplished. The 3D printing files can be modified easily for any space, and are available both on Thingiverse and Printables. For some other ways of packing a lot into a small space, we featured this tiny workshop a while back that’s packed with storage hacks.

Toteable PC Is Inspired By Macs Of Days Gone By

October 14, 2022 by 7 Comments

Back in the 1980s, the personal computer was a hip new thing, and the form this new technology would take was still up for debate. Back then, all kinds of weird clamshells, breadbins, and all-in-one designs hit the market, with the Apple Macintosh proving to be a successful example of the latter. Inspired by the Macintosh 128K that served as their first computer, [Arnov Sharma] decided to whip up a modern all-in-one of their very own.

It’s nicknamed the LATTEintosh, as it’s built around the Latte Panda 3 Delta. This is a single-board computer with an Intel Celeron N5105 CPU, 8GB of RAM, and 64GB of eMMC storage on board. It’s capable of running full-fat x86 operating systems, and here, it’s running Windows 10.

The enclosure is a custom 3D-printed design of [Arnov]’s own creation. It sports a 7-inch HD monitor, fans for cooling, and speakers integrated into the case. Naturally, it’s got a handle on top to make it easy to carry, just like the Macintosh all-in-ones all those years ago.

There’s something to be said for a computer you can just pick up and carry away, and we love the boxy form factor. Sometimes a laptop simply won’t do, and we can imagine many engineers and technicians out there appreciating a build like this. We’ve seen some great all-in-ones before, too. Video after the break.

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2022 Hackaday Supercon Speakers Will Inspire You

October 4, 2022 by 10 Comments

The return of Supercon is taking place in just a month. We’ve got 45 fantastic talks and workshops planned for the three-day weekend, and they are as varied and inspiring as the Hackaday community itself. From molecules to military connectors, here’s an even dozen talks to whet your appetite.

Supercon is the Ultimate Hardware Conference and you need to be there! We’ll continue to announce speakers and workshops over the next couple weeks. Supercon will sell out so get your tickets now before it’s too late. And stay tuned for the next round of talk reveals next week! Continue reading “2022 Hackaday Supercon Speakers Will Inspire You” →

Testing An Inexpensive CNC Spindle

September 12, 2022 by 22 Comments

The old saying “you get what you pay for” is a cautionary cliché, but is directly contrary to several other common sayings. In the case of [Spikee]’s planned CNC machine build, he took the more adventurous idiom of “no risk, no reward” to heart when he purchased these spindles for the machine from AliExpress. While the delivered product seemed fine, there were some problems that needed investigations.

Upon delivery of the spindle, everything seemed to work correctly out-of-the-box. Even the variable frequency drive, which was programmed at the factory, was working properly. But at around 8000 rpm the machine would begin shaking. The suspected part causing the vibration was the tool holder, so after checking the machine’s runout and also using a specialized vibration sensor this was confirmed to be the case.

Luckily [Spikee] was able to get a refund on the tool holders since they were out of spec, but still has a quite capable spindle on his hands for an excellent price. Without some skills in troubleshooting he might have returned the entire machine unnecessarily. If you are looking for some other ideas in setting up an inexpensive CNC machine, you might also like to look at BLDC motors from a remote control vehicle.

A tennis racket and a tennis ball with a spinning motor inside

A Self-Spinning Tennis Ball To Surprise Your Opponent

August 25, 2022 by 6 Comments

In many ball sports like golf, football and tennis, controlling the ball’s spin is an important skill. Expert players can make golf balls curve around obstacles, launch footballs towards goal posts from impossible angles, or confuse their opponents by making a tennis ball bounce in a completely unexpected direction.

[Luis Marx], by his own admission, is not an expert tennis player at all, so when he found himself humiliated on the court by his roommate he set about finding a different way to win. In other words, to cheat. The basic idea was to make a tennis ball that would start spinning at the push of a button, rather than by skillful wielding of a racket: a spinning ball that flies through the air will follow a curved trajectory, so if you can make a ball spin at will, you can change its direction in mid-air.

Making a ball spin by itself is not as hard as it may sound. All you need is an electric motor that’s small enough to fit inside, along with a power source and some way to turn it on. When the motor inside the ball starts to spin, Newton’s third law ensures that the outside will spin in the opposite direction. [Luis] found a suitable DC motor and mounted it on a small custom-designed PCB along with an ESP8266 controller and powered it with a tiny lithium battery. A pushbutton mounted on his tennis racket operates the wireless interface to turn the motor on and off.

Although getting this setup to work wasn’t as easy as [Luis] had hoped, turning it into a ball that’s good enough to play tennis with was not straightforward either. [Luis] decided to 3D-print the outer shell using flexible filament in order to create something that would have the same amount of bounce as an ordinary rubber tennis ball. It took several rounds of trial and error with various types of filament to end up with something that worked, but the final result, as you can see in the video (in German, embedded below), was quite impressive.

Tests on the tennis court showed that [Luis] could now easily beat his roommate, although this was mostly due to the erratic bouncing caused by the ball’s spin rather than any aerodynamic effects. Still, the magic tennis ball achieved its objective and even survived several games without breaking. If you’re looking for a more brute-force approach to cheating at tennis, this 180 mph tennis ball trebuchet might come in handy.

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