Taming The Wobble: An Arduino Self-Balancing Bot

March 9, 2025 by Heidi Ulrich 12 Comments

Getting a robot to stand on two wheels without tipping over involves a challenging dance with the laws of physics. Self-balancing robots are a great way to get into control systems, sensor fusion, and embedded programming. This build by [mircemk] shows how to make one with just a few common components, an Arduino, and a bit of patience fine-tuning the PID controller.

At the heart of the bot is the MPU6050 – a combo accelerometer/gyroscope sensor that keeps track of tilt and movement. An Arduino Uno takes this data, runs it through a PID loop, and commands an L298N motor driver to adjust the speed and direction of two DC motors. The power comes from two Li-ion batteries feeding everything with enough juice to keep it upright. The rest of the magic lies in the tuning.

PID (Proportional-Integral-Derivative) control is what makes the robot stay balanced. Kp (proportional gain) determines how aggressively the motors respond to tilting. Kd (derivative gain) dampens oscillations, and Ki (integral gain) helps correct slow drifts. Set them wrong, and your bot either wobbles like a confused penguin or falls flat on its face. A good trick is to start with only Kp, then slowly add Kd and Ki until it stabilizes. Then don’t forget to calibrate your MPU6050; each sensor has unique offsets that need to be compensated in the code.

Once dialed in, the result is a robot that looks like it defies gravity. Whether you’re hacking it for fun, turning it into a segway-like ride, or using it as a learning tool, a balancing bot is a great way to sharpen your control system skills. For more inspiration, check out this earlier attempt from 2022, or these self-balancing robots (one with a little work) from a year before that. You can read up on [mircemk]’s project details here.

YouTuber Builds Onewheel With Tracks Instead And It’s Not Great

March 22, 2024 by Lewin Day 15 Comments

The one-wheel is a triumph of modern sensor and control technology. That made it possible to sense the acceleration and position of a platform with a single wheel, and to control that single wheel to keep the platform stable and level, even in motion. [RCLifeOn] has now taken that same concept and made it more hilarious by swapping out the wheel for a track.

The original idea was to build an electric snowboard, which worked just okay. Then, it morphed into a tank-based one-wheel instead. It’s a bit silly on the face of it, because a track is more stable than a wheel. That’s because instead of balancing on a small flattened spot of a tire, it’s got a wider, flatter footprint. But that means there’s no real need for balancing control as the track is statically stable.

The 3D-printed track assembly is driven by a powerful brushless motor via a gear drive for additional torque. Riding it is difficult on 48-volt power as it easily throws [RCLifeOn] off the board with its raw torque. At 24 volts, however, it was just barely ridable with some practice. But it was ultimately pretty terrible. It was either not moving at all, or jerking so hard that it was impossible to stay on the thing.

We’d like to see this concept tried again, perhaps with a rubber track and a more refined controller. Video after the break.

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VR Sickness: A New, Old Problem

November 29, 2022 by Donald Papp 56 Comments

Have you ever experienced dizziness, vertigo, or nausea while in a virtual reality experience? That’s VR sickness, and it’s a form of motion sickness. It is not a completely solved problem, and it affects people differently, but it all comes from the same root cause, and there are better and worse ways of dealing with it.

If you’ve experienced a sudden onset of VR sickness, it was most likely triggered by flying, sliding, or some other kind of movement in VR that caused a strong and sudden feeling of vertigo or dizziness. Or perhaps it was not sudden, and was more like a vague unease that crept up, leaving you nauseated and unwell.

Just like car sickness or sea sickness, people are differently sensitive. But the reason it happens is not a mystery; it all comes down to how the human body interprets and reacts to a particular kind of sensory mismatch.

Why Does It Happen?

The human body’s vestibular system is responsible for our sense of balance. It is in turn responsible for many boring, but important, tasks such as not falling over. To fulfill this responsibility, the brain interprets a mix of sensory information and uses it to build a sense of the body, its movements, and how it fits in to the world around it.

These sensory inputs come from the inner ear, the body, and the eyes. Usually these inputs are in agreement, or they disagree so politely that the brain can confidently make a ruling and carry on without bothering anyone. But what if there is a nontrivial conflict between those inputs, and the brain cannot make sense of whether it is moving or not? For example, if the eyes say the body is moving, but the joints and muscles and inner ear disagree? The result of that kind of conflict is to feel sick.

Common symptoms are dizziness, nausea, sweating, headache, and vomiting. These messy symptoms are purposeful, for the human body’s response to this particular kind of sensory mismatch is to assume it has ingested something poisonous, and go into a failure mode of “throw up, go lie down”. This is what is happening — to a greater or lesser degree — by those experiencing VR sickness.

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Balancing A Motor With An Oscilloscope

June 18, 2022 by Dan Maloney 17 Comments

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

February 24, 2022 by Bryan Cockfield No comments

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

June 12, 2020 by Dan Maloney 29 Comments

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

December 26, 2019 by Jenny List 19 Comments

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.