Balancing A Motor With An Oscilloscope

With all things in life, one must seek to achieve balance. That may sound a little like New Age woo-woo, but if you think it’s not literally true, just try tolerating a washing machine with a single comforter on spin cycle, or driving a few miles on unbalanced tires.

Anything that rotates can quickly spin itself into shrapnel if it’s not properly balanced, and the DIY power tools in [Matthias Wandel]’s shop are no exception. Recent upgrades to his jointer have left the tool a bit noisy, so he’s exploring machine vibrations with this simple but clever setup. Using nothing but a cheap loudspeaker and an oscilloscope, [Matthias] was able to characterize vibrations in a small squirrel-cage blower — he wisely chose to start small to validate his method before diving into the potentially dangerous jointer. There was quite a lot to be learned from the complex waveforms coming back from the transducer, analysis of which was greatly helped by the scope’s spectrum analyzer function. The video below shows the process of probing various parts of the blower, differentiating spectral peaks due to electrical noise rather than vibration, and actually using the setup to dynamically balance the fan.

We’d rate this as yet another handy shop tip from [Matthias], and we’ll be looking out for the analysis of his jointer. Want to do the same but you don’t have an oscilloscope? No problem — an earbud and Audacity might be all you need.

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Prototype Robot For Omniwheel Bicycle

For all its ability to advance modern society in basically every appreciable way, science still has yet to explain some seemingly basic concepts. One thing that still has a few holes in our understanding is the method by which a bicycle works. Surely, we know enough to build functional bicycles, but like gravity’s inclusion into the standard model we have yet to figure out a set of equations that govern all bicycles in the universe. To push our understanding of bicycles further, however, some are performing experiments like this self-balancing omniwheel bicycle robot.

Functional steering is important to get the bicycle going in the right direction, but it’s also critical for keeping the bike upright. This is where [James Bruton] is putting the omniwheel to the test. By placing it at the front of the bike, oriented perpendicularly to the direction of travel, he can both steer the bicycle robot and keep it balanced. This does take the computational efforts of an Arduino Mega paired with an inertial measurement unit but at the end [James] has a functional bicycle robot that he can use to experiment with the effects of different steering methods on bicycles.

While he doesn’t have a working omniwheel bicycle for a human yet, we at least hope that the build is an important step on the way to [James] or anyone else building a real bike with an omniwheel at the front. Hopefully this becomes a reality soon, but in the meantime we’ll have to be content with bicycles with normal wheels that can balance and drive themselves.

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Cheap Lab Balance Needs Upgrades, Gets Gutted Instead

What is this world coming to when you spend seven bucks on a digital scale and you have to completely rebuild it to get the functionality you need? Is nothing sacred anymore?

Such were the straits [Jana Marie] found herself in with his AliExpress special, a portable digital scale that certainly looks like it’s capable of its basic task. Sadly, though, [Jana] was looking for a few more digits of resolution and a lot more in the way of hackability. And so literally almost every original component was ripped out of the scale, replaced by a custom PCB carrying an STM32 microcontroller and OLED display. The PCB has a complicated shape that allows the original lid to attach to it, as well as the stainless steel pan and load cell. [Jana] developed new firmware that fixes some annoying traits, for example powering down after 30 seconds, and adds new functionality, such as piece-counting by weight. The video below shows some of the new features in action.

Alas, [Jana] reports that even the original load cell must go, as it lacks the accuracy her application requires. So she’ll essentially end up building the scale from scratch, which we respect, of course. At this rate, she might even try to build her own load cell from SMD resistors too.

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Open-Source Analytical Balance Pits Gravity Against Electromagnetism

As the open-source movement has brought its influence to more and more fields, we’ve seen an astonishing variety of things once only available at significant expense become accessible to anyone with access to the tools required to create them. One such arena is that of scientific instrumentation, and though we have seen many interesting developments there has been one which has so far evaded us. An analytical balance, a very specialised weighing machine designed to measure the tiniest of masses, remains available only as a new unit costing a fortune, or as a second-hand one with uncertain history and possible contamination. Fortunately, friend of Hackaday [Zach Fredin] is on the case, and as part of one of his MIT courses he chose to create an open-source analytical balance.

The write-up is interspersed with his course notes as he learns a series of fabrication techniques, but in addition to the milled Delrin finished model he treats us to his prototype and gives us an explanation of how these instruments work. It’s a technique that’s rather different to a traditional weighing machine: instead of measuring deformation of a spring in some way it produces a force from an electromagnet to oppose that exerted by gravity on the mass to be measured, and quantifies how much electrical energy is required to do that. The mechanism incorporates feedback through a vane and an optical sensor, which he admits he’s not yet had time to set up properly.

It’s an interesting project not least because it exposes some of the inner workings of an analytical balance, and we look forward to his completing it. If this whet your appetite for the topic it’s worth also looking at [Ben Krasnow’s] video of a balance made using a moving coil meter for an explanation of the technique.

Balance Box Game Requires A Steady Hand

In the distant past, engineers used exotic devices to measure orientation, such as large mechanical gyros and mercury tilt switches. These are all still useful methods, but for many applications MEMS motions devices have become the gold standard. When [g199] set out to build their Balance Box game, it was no exception.

The game consists of a plastic box, upon which a spirit level is fitted, along with a series of LEDs. The aim of the game is to keep the box level while carrying it to a set goal. Inside, an Arduino Uno monitors the output of a MPU 6050, a combined accelerometer and gyroscope chip. If the Arduino detects the box is tilting, it warns the user with the LEDs. Tilt it too far, and a life is lost. When all three lives are gone, the game is over.

It’s a cheap and simple build that would have been inordinately more expensive only 10 to 20 years ago. It goes to show the applications enabled by ubiquitous cheap electronics like MEMS sensors. The technology has other fun applications, too – for example the Stecchino game, or this giant balance board joystick. We’re certainly lucky to have such powerful technology at our fingertips!

Cheating The Perfect Wheelie With Sensors And Servos

Everyone remembers popping their first wheelie on a bike. It’s an exhilarating moment when you figure out just the right mechanics to get balanced over the rear axle for a few glorious seconds of being the coolest kid on the block. Then gravity takes over, and you either learn how to dismount the bike over the rear wheel, or more likely end up looking at the sky wondering how you got on the ground.

Had only this wheelie cheating device been available way back when, many of us could have avoided that ignominious fate. [Tom Stanton]’s quest for the perfect wheelie led him to the design, which is actually pretty simple. The basic idea is to apply the brakes automatically when the bike reaches the critical angle beyond which one dares not go. The brakes slow the bike, the front wheel comes down, and the brakes release to allow you to continue pumping along with the wheelie. The angle is read by an accelerometer hooked to an Arduino, and the rear brake lever is pulled by a hobby servo. We honestly thought the servo would have nowhere near the torque needed, but in fact it did a fine job. As with most of [Tom]’s build his design process had a lot of fits and starts, but that’s all part of the learning. Was it worth it? We’ll let [Tom] discuss that in the video, but suffice it to say that he never hit the pavement in his field testing, although he appeared to be wheelie-proficient going into the project.

Still, it was an interesting build, and begs the question of how the system could be improved. Might there be some clues in this self-balancing motorized unicycle?

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Ask Hackaday: Managing Inspiration

For most of us, hacking is a hobby, something to pass a few idle hours and satisfy our need to create. Precious few of us get to live the dream of being paid to tinker; most of us need some kind of day job to pay the bills and support our hacking habits. This necessarily creates an essential conflict, rooted in the fact that we all only have 24 hours to spread around every day: I need to spend my time working so I can afford to hack, but the time I spend working to earn money eats away at my hacking time. That’s some catch, that Catch-22.

From that primary conflict emerges another one. Hacking is a hugely creative process, and while the artist or the author might not see it that way, it’s true nonetheless. Unless we’re straight-up copying someone else’s work, either because they’ve already solved the same problem we’re working on and we just need to get it done, or perhaps we’re just learning a new skill and want to stick to the script, chances are pretty good that we’re hitting the creative juices hard when we build something new. And that requires something perhaps even more limiting than time: inspiration. How you manage inspiration in large part dictates how productive you are in your creative pursuits.

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