Year: 2021

Julius Sumner Miller Made Physics Fun For Everyone

May 5, 2021 by 38 Comments

Let’s face it — for the average person, math and formulas are not the most attractive side of physics. The fun is in the hands-on learning, the lab work, the live action demonstrations of Mother Nature’s power and prowess. And while it’s true that the student must be willing to learn, having a good teacher helps immensely.

Professor Julius Sumner Miller was energetic and enthusiastic about physics to the point of contagiousness. In pictures, his stern face commands respect. But in action, he becomes lovable. His demonstrations are dramatic, delightful, and about as far away from boring old math as possible. Imagine if Cosmo Kramer were a physics professor, or if that doesn’t give you an idea, just picture Doc Brown from Back to the Future (1985) with a thick New England accent and slightly darker eyebrows. Professor Miller’s was a shouting, leaping, arm-waving, whole-bodied approach to physics demonstrations. He was completely fascinated by physics, and deeply desired to understand it as best he could so that he could share the magic with people of all ages.

Professor Miller reached thousands of students in the course of his nearly 40-year teaching career, and inspired millions more throughout North America and Australia via television programs like The Mickey Mouse Club and Miller’s own show entitled Why Is It So? His love for science is indeed infectious, as you can see in this segment about the shock value of capacitors.

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3D Printed Camera Crane For The Workshop

May 5, 2021 by 7 Comments

When you make a living building stuff and documenting the process camera setups take up a lot of time, breaking expensive equipment is an occupational hazard. [Ivan Miranda] knows this all too well, so he built a fully-featured camera crane to save his time and camera equipment. Video after the break.

The basic design is a vertical mast with a pivoting camera mounted to the end. The aluminum mast telescopes for increased vertical adjustability, and rides on a plywood base with caster wheels. The aluminum pivoting arm is counterweighed to offset the camera head, and a parallel bar mechanism allows the camera to hold a constant vertical angle with the ground. Thanks to the explosion of home gyms during the pandemic, gym weights were hard to find, so [Ivan] used an ammo can filled with sand and screws instead. A smaller sliding counterweight on top of the arm allows for fine-tuning. [Ivan] also wanted to be able to do horizontal sliding shots, so he added a pulley system that can be engaged with a clutch mechanism to keep a constant horizontal angle with the camera. Most of the fittings and brackets are 3D printed, some of them no doubt on his giant 3D printer.

We can certainly see this crane meeting its design objectives, and we can’t help but want one ourselves. [Alexandre Chappel] also built a camera crane a while back which utilized a completely different arm mechanism. As cool as these are, they still pale in comparison to [mingul]’s workshop-sized 8-axis CNC camera crane. Continue reading “3D Printed Camera Crane For The Workshop” →

The Soviet RBMK Reactor: 35 Years After The Chernobyl Disaster

May 5, 2021 by 66 Comments

Thirty-five years ago, radiation alarms went off at the Forsmark nuclear power plant in Sweden. After an investigation, it was determined that the radiation did not come from inside the plant, but from somewhere else. Based on the prevailing winds at that time, it was ultimately determined that the radiation came from inside Soviet territory. After some political wrangling, the Soviet government ultimately admitted that the Chernobyl nuclear plant was the source, due to an accident that had taken place there.

Following the disaster, the causes have been investigated in depth so that we now have a fairly good idea of what went wrong. Perhaps the most important lesson taught by the Chernobyl nuclear plant disaster is that it wasn’t about one nuclear reactor design, one control room crew, or one totalitarian regime, but rather the chain of events which enabled the disaster of this scale.

To illustrate this, the remaining RBMK-style reactors — including three at the Chernobyl plant — have operated without noticeable issues since 1986, with nine of these reactors still active today. During the international investigation of the Chernobyl plant disaster, the INSAG reports repeatedly referred to the lack of a ‘safety culture’.

Looking at the circumstances which led to the development and subsequent unsafe usage of the Chernobyl #4 reactor can teach us a lot about disaster prevention. It’s a story of the essential role that a safety culture plays in industries where the cost of accidents is measured in human life.

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Modified Microwave Cures Resin Parts With Style

May 5, 2021 by 18 Comments

Once you make the leap to resin-based 3D printing, you’ll quickly find that putting parts out in the sun to cure isn’t always a viable solution. The best way to get consistent results is with a dedicated curing chamber that not only rotates the parts so they’re evenly exposed to the light, but allows you to dial in a specific curing time. A beeper that goes off when the part is done would be handy as well. Wait, this is starting to sound kind of familiar…

As you might expect, [Stynus] isn’t the first person to notice the similarities between an ideal UV curing machine and the lowly microwave oven. But his conversion is certainly one of the slickest we’ve ever seen. The final product doesn’t look like a hacked microwave so much as a purpose-built curing machine, thanks in large part to the fact that all of the original controls are still functional.

The big break there came when [Stynus] noticed that the control panel was powered by a one-time programmable PIC16C65B microcontroller. Swapping that out for the pin-compatible PIC16F877A opened up the possibility of writing custom firmware to interface with all the microwave’s original hardware, he just needed to reverse engineer how it was all wired up. It took some time to figure out how the limited pins on the microcontroller ran the LED display and read the buttons and switches at the same time, but we’d say the final result is more than worth the work.

With full control over the microwave’s hardware, all [Stynus] had to do was strip out all the scary high voltage bits (which were no longer functional to begin with) and install an array of UV LEDs. Now he can just toss a part on the plate, spin the dial to the desired curing time, and press a button. In the video below, you can see he’s even repurposed some of the buttons on the control panel to let him do things like set a new default “cook” time to EEPROM.

Compared to the more traditional fused deposition modeling (FDM) 3D printers, resin printing requires a lot of additional post-processing and equipment. You don’t necessarily have to gut your microwave just to cure your prints, but you’d be wise to fully consider your workflow will look like before pulling the trigger on that shiny new printer.

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RCA Plug Plays Sixteen-Minute Chiptune Piece, All By Itself

May 5, 2021 by 12 Comments

Frequenters of arcades back in the golden age of video games will likely recall the mix of sounds coming from a properly full arcade, the kind where you stacked your quarters on a machine to stake your claim on being next in line to play. They were raucous places, filled with the simple but compelling sounds that accompanied the phosphor and silicon magic unfolding all around.

The days of such simple soundtracks may be gone, but they’re certainly not forgotten, with this chiptunes generator built into an RCA plug being both an homage to the genre and a wonderful example of optimization and miniaturization. It’s the work of [girst] and it came to life as an attempt to implement [Rob Miles]’ Bitshift Variations in C Minor algorithmically generated chiptunes composition in hardware. For the first attempt, [girst] chose an ATtiny4 as the microcontroller, put it and the SMD components needed for a low-pass filter on a flex PCB, and wrapped the whole thing around a button cell battery. Stuffed into the shell of an RCA plug, the generator detects when it has been inserted into an audio input jack and starts the 16-minute piece. [girst] built a second version, too, using the Padauk PSM150c “Three-Cent Microcontroller” chip.

This is quite an achievement in chiptunes minimization. We’ve seen chiptunes in 32 bytes, Altoids tin chiptunes, and an EP on a postage-stamp-sized PCB, but this one might beat them all on size alone.

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Lego Wheels And Tracks Benchmarked For Your Pleasure

May 4, 2021 by 7 Comments

For many people, Lego is their first entry into the world of engineering. With the Technic line of building blocks complete with all manner of gears and shafts and wheels, there’s a ton of fun to be had while learning about the basic principles of mechanical things. The [Brick Experiment Channel] takes Lego quite seriously in this context, and has collected data concerning the performance of a variety of Lego wheels and tracks.

The testing setup is simple. A small vehicle is fitted with a particular set of Lego wheels or tracks. Then, it’s placed on an inclined wooden board. The angle of inclination is then increased until the vehicle neither climbs the board nor slips down it. This angle can then be used to calculate the coefficient of friction of the given tyre or track set. [Brick Experiment Channel] filmed this testing and collected data on 33 different wheel and track combinations, publishing it in the description of the Youtube video.

Interestingly, the date of release of the various parts is recorded with the data. This is interesting as one would expect older rubber parts to lose grip with age, however, the release date of the parts obviously does not correspond with the manufacturing date, so the utility of this is somewhat unclear. There’s also some surprising results, with what appear to be soft, flat and smooth rubber wheels performing somewhat worse than those with curved profiles that you’d expect to have less contact patch. Regardless, it’s the best data we’ve ever seen in this field and we think it’s great that it was collected and shared with the broader Lego community. We look forward to seeing more of this in future, as it’s obviously something of great use to builders. We can imagine it would have proved handy when [Brick Experiment Channel] built their obstacle climbing rover. Video after the break.

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AVR Bare Metal With Lisp

May 4, 2021 by 21 Comments

There are two kinds of programmers: those who don’t use Lisp, and those who need new parenthesis keycaps every six months. Lisp is one of those languages you either really love or really hate. If you love it, you may have checked out ulisp, which runs on Arduino boards of the AVR and ARM variety, as well as ESP chips, RISC-V, and others. A recent update allows the language to insert assembler into AVR programs.

We probably don’t need to convince anyone reading Hackaday why adding assembler is a good thing. It seems to integrate well with the environment, too, so you can write assembler macros in Lisp, which opens up many possibilities.

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