Monowheel Mayhem: When Good Gyroscopic Precession Goes Bad

January 19, 2022 by Ryan Flowers 11 Comments

Since the dawn of the age of the automobile, motorheads have been obsessed with using as few wheels as possible. Not satisfied with the prospect of being incompletely maimed by a motorcycle, the monocycle was born. Gracing the covers of Popular magazines and other periodicals, these futuristic wheels of doom have transfixed hackers of all kinds. [James Bruton] is one such hacker, and in the video below the break you can see his second iteration of a 3d printed monowheel.

[James]’ wonderful monowheel is beautifully engineered. Bearing surfaces, gears, idlers, motors, and yes, twin gyroscopes are all contained within the circumference of the tire. The gyroscopes are actuated by a rather large servo, and are tied together by a gear that keeps their positions in sync. Their job is to keep the monowheel balanced at all times.

But as [James] discovered, the chief difficulty of only having one wheel isn’t lateral balancing. Ask any monocyclist and they’ll assure you that it’s possible. The real trick is balancing the machine fore and aft. Unlike a two wheeled velocipede, the monowheel has nothing to exert torque against save for a bit of gravity.

As [James] found out the hard way, it was within this fore-aft balancing act that the gyroscopic precession reared its ugly head. The concept is explained well in the video. We won’t spoil the surprise ending because the explanation and conclusion are quite good so make sure to watch to the end!

If you’d like to look at [James]’ first version, we covered it here. And if you’re the daredevil type, perhaps we can interest in you in a two stroke human sized monowheel that will probably end in an ER visit. At least they wore a helmet. Thanks to [Baldpower] for the tip!

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1949 Gyroscope Spins Up Again

August 29, 2021 by Al Williams 10 Comments

[Curious Marc] has an Apollo-era gyroscope but isn’t quite ready to put it through this paces without some practice. So he borrowed a 1949 vintage Sperry C5 gyro and did some experiments with it using a 3-phase power supply he plans to use on the other gyro.

There is a little bit of troubleshooting and a lot of gorgeous close up shots of these electromechanical marvels. They sure are noisy, though.

[Marc] wanted a gyro testing table that can control the orientation of a gyro under test. He went the auction route to get a pretty expensive piece of gear for a relatively low price but without the expensive software. In a stroke of luck, he managed to score the required software from the vendor who was intrigued by his project. It looked to us like a table like this wouldn’t be that hard to build from scratch, either.

We are interested in what [Marc] will do with his gyros next. It is hard to imagine that gyros have come from this sort of device to a tiny IC inertial measurement unit that can fit in a phone. Imagine packing the Sperry unit on your next walking robot or self-balancing unicycle.

Need a refresher on how gyro’s work? We got that, too. It even covers the modern kind.

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Actively Balancing A Robot With A Gyroscope

May 17, 2021 by Danie Conradie 9 Comments

Self-balancing robots are a common hacker project, but we don’t often see them using spinning gyroscopes to achieve that balance. Robot master [James Bruton] decided to build a robotic platform with active gyroscopic stabilization, starting from a simple proof of concept.

A gyroscope can balance, but cannot actively counteract external forces directly. However, if the gyroscope is tilted around an axis it will exert a force perpendicular to that axis of tilt, known as gyroscopic precession. By tilting the gyroscope with an actuator, and orienting the gyroscope correctly, gyroscopic precession can be used for stabilization. This is known as a control moment gyroscope. [James] demonstrated this with a 3D printed proof of concept, which is used as an IMU to measure the angle of tilt, and use a PID loop to correct the imbalance with a servo actuating the gyroscope.

His second platform used a pair of gyroscopes spinning in opposite directions to compensate for any unintended gyroscopic precession along another axis. A pair of roller skate wheels allow the entire platform to roll along. Due to a slight imbalance in the platform, [James] noticed that the gyroscopes will continue to creep in one direction, until reaching the end-stops and falling over. By adding a second software controller to keep track of how much the gyroscopes have to move to maintain balance, it can continuously calculate and update the balancing point. This prevents the gyroscopes from hitting the end stops.

Control moment gyroscopes are commonly used for attitude control on spacecraft, and to reduce the rolling motion of boats in waves. [James] has plans to combine a control moment gyroscope with the more conventional balancing method, to balance a robot on a single wheel.

We’ve seen a two wheeled RC cars use gyroscopes before, but without the active control part.
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Gyroscope Level Is Digital

November 15, 2020 by Al Williams 33 Comments

A spirit level, you know the kind of level with a little bubble in a tube of fluid, is a basic construction tool. [DesignBuildDestroy] took an Arduino, a gyroscope chip, and an OLED, and made a 3D printed level with no bubble, but it does have a nice digital display.

It is funny when you realize that at one time a gyroscope was a high tech item reserved for missiles and aircraft. Now you can grab a six-axis sensor for pennies. Even, better, the code used in the project can offload the Arduino for a lot of processing.

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Peripheral Doesn’t Need Deskspace

September 11, 2020 by Brian McEvoy 9 Comments

Some of us are suckers for new hardware. There’s absolutely nothing shameful about a drawer overflowing with gamepads, roll-up keyboards, and those funny-shaped ergonomic mice. MyTeleTouch won’t sate your itch for new hardware because [Dimitar Danailov] didn’t design hardware you hold, because it uses your phone as a catch-all Human Interface Device, HID. A dongle plugs into a standard USB port, and your Android phone can emulate a USB keyboard, mouse, or gamepad over Bluetooth.

Chances are high that you already set up your primary computer with your favorite hardware, but we think we’ve found a practical slant for a minimalist accessory. Remember the last time you booted an obsolete Windows desktop and dug out an old mouse with a questionable USB plug? How long have you poked around the bottom of a moving box trying to find a proprietary wireless keyboard dongle, when you just wanted to type a password on your smart TV? What about RetroPi and a game controller? MyTeleTouch isn’t going to transform your daily experience, but it’ll be there when you don’t want to carry a full-size keyboard down three flights of stairs to press {ENTER} on a machine that spontaneously forgot it has a touch screen. If you don’t have opportunities to play the hero very often, you can choose to play the villain. Hide this in a coworker’s USB port, and while they think you’re sending a text message, you could be fiddling with their cursor.

We enjoy a good prank that everyone can laugh off, and we love little keyboards and this one raises the (space) bar.

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Fighter Jet’s Gyro Stays Upright Before It Self-Destructs

June 3, 2020 by Moritz v. Sivers 18 Comments

Aviation instruments are highly interesting pieces of engineering, and it is quite satisfying to watch the often over-engineered mechanisms behind them. If you are into that sort of thing it is worthwhile to check out [Erik Baigar]’s video where he explains the working principle of the attitude indicator from a Tornado jet.

The attitude indicator or artificial horizon of an airplane is one of the most important instruments, especially during poor sight. The ADI42-124 used in the Tornado jet is completely standalone and only needs a DC power supply which is why [Erik Baigar] can show it off while standing on his balcony. At the heart of this instrument is a gyroscope which consists of a spinning disc attached to a gimbal mount. Due to the conservation of angular momentum, the spin axis will always keep its orientation when the instrument is rotated. However, mechanical gyroscopes tend to drift over time and therefore include a mechanism to keep the spin axis upright with respect to the direction of gravity. The ADI42-124 uses an entirely mechanical mechanism for this based on free swiveling weights. Forget everything we said earlier about overengineering as [Erik Baigar] also uncovers a fatal design flaw which leads to the instrument’s self-destruction as shown in the picture here. Unfortunately, this will render most of the units you can buy on eBay useless.

Be sure to check out [Erik Baigar]’s webpage which is nerd paradise for vintage computer and avionics fans or watch another gyroscope teardown.

Video after the break.

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Gyroscopic Wi-Fi LED Die Is Pretty Fly

March 23, 2020 by Kristina Panos 9 Comments

As cool as sculptural LED cubes are, the only thing you can really do is look at them. They’re not going to stand up to a lot of handling, and as tedious as it is to bend all those leads when building them, you probably wouldn’t want to mess with them anyway.

LED dice on the other hand are robust, blinky playthings with many possibilities, especially if they have a gyroscope and wireless control like the one [moekoe] built. Inside this tiny 25cm³ die is the equally small ESP8285-01F, which lets [moekoe] control the rainbow light show with a Blynk app.

As you will see in the excellent build video that makes this build look challenging instead of impossible, the cube gets permanently sealed up with solder joints. Most but not all of these transfer power, ground, and data around the faces.

Once the cube is together, [moekoe] uses pogo pins to program it, and can charge the little LiPo inside through contact pads. We love the idea of using a cubical printed jig to help solder the PCB edges together, but not as much as we love [moekoe]’s home-brewed SMT soldering setup.

If you want an easier way to make sculptural LED cubes, build yourself a lead-formin’ machine.

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