You Are Already Traveling At The Speed Of Light

March 10, 2025 by Al Williams 40 Comments

Science fiction authors and readers dream of travelling at the speed of light, but Einstein tells us we can’t. You might think that’s an arbitrary rule, but [FloatHeadPhysics] shows a different way to think about it. Based on a book he’s been reading, “Relativity Visualized,” he provides a graphic argument for relativity that you can see in the video below.

The argument starts off by explaining how a three-dimensional object might appear in a two-dimensional world. In this world, everything is climbing in the hidden height dimension at the exact same speed.

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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.

This Laser Knows About Gasses

March 7, 2025 by Al Williams 5 Comments

What’s that smell? If you can’t tell, maybe a new laser system from CU Bolder and NIST can help. The device is simple and sensitive enough to detect gasses at concentrations down to parts per trillion.

The laser at the system’s heart is a frequency comb laser, originally made for optical atomic clocks. The laser has multiple optical frequencies in its output. The gas molecules absorb light of different wavelengths differently, giving each type of molecule a unique fingerprint.

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China Claims Commercial Nuclear Fusion By 2050 As Germany Goes Stellarator

March 5, 2025 by Maya Posch 49 Comments

Things are heating up in the world of nuclear fusion research, with most fundamental issues resolved and an increasing rate of announcements being made regarding commercial fusion power. China’s CNNC is one of the most recent voices here, with their statement that they expect to have commercial nuclear fusion plants online by 2050. Although scarce on details, China is one of the leading nations when it comes to nuclear fusion research, with multiple large tokamaks, including the HL-2M and the upcoming CFETR which we covered a few years ago.

Stellaris stellarator. (Credit: Proxima Fusion)

In addition to China’s fusion-related news, a German startup called Proxima Fusion announced their Stellaris commercial fusion plant design concept, with a targeted grid connection by the 2030s. Of note is that this involves a stellarator design, which has the major advantage of inherent plasma stability, dodging the confinement mode and Greenwald density issues that plague tokamaks. The Stellaris design is an evolution of the famous Wendelstein 7-X research stellarator at the Max Planck Institute.

While Wendelstein 7-X was not designed to produce power, it features everything from the complex coiled design and cooled divertors plus demonstrated long-term operation that a commercial reactor would need. This makes it quite likely that the coming decades we’ll be seeing the end spurt for commercial fusion power, with conceivably stellarators being the unlikely winner long before tokamaks cross the finish line.

Make Your Own Air Knife And Air Amplifier

March 3, 2025 by Maya Posch 20 Comments

Want to make your own air knife to cut things with? Unfortunately that’s not what these devices are intended for, but [This Old Tony] will show you how to make your own, while explaining what they are generally intended for. His version deviates from the commercial version which he got his hands on in that he makes a round version instead of the straight one, but the concept is the same.

In short, an air knife is a laminar pressurized airflow device that provides a very strong and narrow air pattern, using either compressed air or that from a blower. Generally air knives will use the Coandă effect to keep the laminar flow attached to the device for as long as possible to multiply the air pressure above that from the laminar flow from the air knife itself. These are commonly used for cleaning debris and dust off surfaces in e.g. production lines.

As [Tony] shows in the disassembly of a commercial device, they are quite basic, with just two aluminium plates and a thin shim that creates the narrow opening through which the air can escape. The keyword here is ‘thin shim’, as [Tony] discovers that even a paper shim is too thick already. Amusingly, although he makes a working round air knife this way, it turns out that these are generally called an air amplifier, such as those from Exair and are often used for cooling and ventilation, with some having an adjustable opening to adjust the resulting airflow.

Some may recognize this principle for those fancy ‘bladeless’ fans that companies like Dyson sell, as they use essentially the same principle, just with a fan providing the pressure rather than a compressor.

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Sensory Substitution Device Tingles Back Of Your Hand

March 3, 2025 by Arya Voronova 3 Comments

A team from the University of Chicago brings us a new spin on sensory substitution, the “Seeing with the Hands” project, turning external environment input into sensations. Here specifically, the focus is on substituting vision into hand sensations, aimed at blind and vision disabled. The prototype is quite inspiration-worthy!

On the input side, we have a wrist-mounted camera, sprinkled with a healthy amount of image processing, of course. As for the output, no vibromotors or actuators are in use – instead, tactile receptors are stimulated by passing small amounts of current through your skin, triggering your touch receptors electrically. An 5×6 array of such “tactile” pixels is placed on the back of the hand and fingers. The examples provided show it to be a decent substitution.

This technique depends on the type of image processing being used, as well as the “resolution” of the pixels, but it’s a fun concept nevertheless, and the study preprint has some great stories to tell. This one’s far from the first sensory substitution devices we’ve covered, though, as quite a few of them were mechanical in nature – the less moving parts, the better, we reckon!

A PCR machine with its side cover taken off exposing its guts, and the tray extended out

Making A PCR Machine Crypto Sign Its Results

March 1, 2025 by Arya Voronova 20 Comments

Money, status, or even survival – there’s no shortage of incentives for faking results in the scientific community. What can we do to prevent it, or at least make it noticeable? One possible solution is cryptographic signing of measurement results.

Here’s a proof-of-concept from [Clement Heyd] and [Arbion Halili]. They took a ThermoFisher Scientific 7500 Fast PCR (Polymerase Chain Reaction) machine, isolated its daughter-software, and confined it into a pipeline that automatically signs each result with help of a HSM (Hardware Security Module).

A many machines do, this one has to be paired to a PC, running bespoke software. This one’s running Windows XP, at least! The software got shoved into a heavily isolated virtual machine running XP, protected by TEE (Trusted Execution Environment). The software’s output is now piped into a data diode virtual serial port out of the VM, immediately signed with the HSM, and signed data is accessible through a read-only interface. Want to verify the results’ authenticity? Check them against the system’s public key, and you’re golden – in theory.

This design is just a part of the puzzle, given a typical chain of custody for samples in medical research, but it’s a solid start – and it happens to help make the Windows XP setup more resilient, too.

Wondering what PCR testing is good for? Tons of things all over the medical field, for instance, we’ve talked about PCR in a fair bit of detail in this article about COVID-19 testing. We’ve also covered a number of hacker-built PCR and PCR-enabling machines, from deceivingly simple to reasonably complex!