An odd looking apparatus for cleaning floppy disks. A neon green disk tray is suspended on metal linear rails in a vertical orientation. It can move back and forth through a set of cleaning heads and a set of drying fans. There are some control buttons on the font as well as a string of addressable LEDs and two speakers.

Rube Goldberg Floppy Disk Cleaner

Floppies were once the standard method of information exchange, but decades of storage can render them unreadable, especially if mold sets in. [Rob Smith] wanted to clean some floppies in style and made a Disco Rube Goldberg-Style device for the job.

Starting with a disk caddy on linear rails, [Smith] has a track for the floppy to follow. First it goes through a set of pads with cleaning solution on them, and is then dried off with heating elements. To make it more fun, the device has LEDs and a set of speakers at the bottom to treat the disk to a more complete car wash-esque experience.

Cotton swabs and a cleaning solution are all you really need to do the job by hand, but if you have a lot of floppies, that can get tedious quickly. [Smith] compares his machine’s performance to doing it by hand with both IPA and a dish soap solution showing that his machine does indeed clean the disks and usually makes them more readable than they were before. He cautions that it might be best to make multiple copies of the disk during the cleaning process as it isn’t always constructive though.

Thinking about archiving that stack of floppies under your workbench? While Linux doesn’t support the drives anymore, we’ve covered a couple different methods in the past and the importance of reading the flux.

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A finger points at a diagram of a battery with two green bars. Above it is another battery with four smaller green bars with a similar area to the first battery's two. The bottom batter is next to a blue box with a blue wave emanating from it and the top battery has a red box with a red wave emanating from it. Below the red wave is written "2x wavelength" and below the top battery is "1/2 energy in a photon."

What Are Photons, Anyway?

Photons are particles of light, or waves, or something like that, right? [Mithuna Yoganathan] explains this conundrum in more detail than you probably got in your high school physics class.

While quantum physics has been around for over a century, it can still be a bit tricky to wrap one’s head around since some of the behaviors of energy and matter at such a small scale aren’t what we’d expect based on our day-to-day experiences. In classical optics, for instance, a brighter light has more energy, and a greater amplitude of its electromagnetic wave. But, when it comes to ejecting an electron from a material via the photoelectric effect, if your wavelength of light is above a certain threshold (bigger wavelengths are less energetic), then nothing happens no matter how bright the light is.

Scientists pondered this for some time until the early 20th Century when Max Planck and Albert Einstein theorized that electromagnetic waves could only release energy in packets of energy, or photons. These quanta can be approximated as particles, but as [Yoganathan] explains, that’s not exactly what’s happening. Despite taking a few classes in quantum mechanics, I still learned something from this video myself. I definitely appreciate her including a failed experiment as anyone who has worked in a lab knows happens all the time. Science is never as tidy as it’s portrayed on TV.

If you want to do some quantum mechanics experiments at home (hopefully with more luck than [Yoganathan]), then how about trying to measure Planck’s Constant with a multimeter or LEGO? If you’re wondering how you might better explain electromagnetism to others, maybe this museum exhibit will be inspiring.

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A painted RC plane made of cardboard. It has an orange propeller and camo-esque markings along with concentric blue, white, and red circles near the wingtips.

Cardboard R/C Plane Actually Flies

Many makers start by building mock-ups from cardboard, but [Alex-08] has managed to build an R/C plane that actually flies, out of cardboard.

If you’ve been thinking of building an R/C plane from scratch yourself, this guide is an excellent place to start. [Alex-08] goes through excruciating detail on how he designed and constructed this marvel. The section on building the wings is particularly detailed since that’s the most crucial element in making sure this plane can get airborne.

Some off-the-shelf R/C parts and 3D printed components round out the parts list to complement the large cardboard box used for most of the structural components. The build instructions even go through some tips on getting that vintage aircraft feel and how to adjust everything for a smooth flight.

Need a wind tunnel instead? You can build that out of cardboard too. If paper airplanes are more your thing, how about launching them from space? And if you’re just trying to get a head start on Halloween, why not laser cut an airplane costume from cardboard?

A map of the US showing the potential changes to passenger rail service due to the Corridor ID Program

A New Era For US Passenger Rail?

Here in the United States, we’re lagging behind the rest of the world when it comes to shiny new passenger rail, despite being leaders in previous centuries. The Federal Railroad Administration (FRA) has just released a story map of how the US could close the gap (a little).

A new blue and white high speed train crosses a brick bridge. There is what looks like a park beneath and a cityscape in the background.The Corridor Identification and Development (CID) Program is a way for FRA to provide both funding and technical assistance as corridor sponsors (mostly state Departments of Transportation) evaluate either new intercity service or expansion of existing services. While it isn’t a guarantee of anything, it is a step in the right direction to rebuilding passenger rail capacity in the US.

Some cities would be getting rail service back for the first time in decades, and perhaps even more exciting is that several of the routes being studied are for high speed rail “primarily or solely on new trackage.” As any railfan can tell you, vintage rails aren’t the best for trains going fast (sorry, Acela). With recent polling showing strong public support for the build out of high speed rail, it’s an exciting time for those who prefer to travel by rail.

We don’t think you’ll be able to ride a gyro monorail, nuclear-powered, or jet train on these proposed routes, but we do hope that Amtrak and FRA are looking to the state-of-the-art when it comes to those high speed alignments. While you’re eagerly awaiting new passenger service, might we recommend this field guide to what all those different freight cars going by are for here in North America?

A man's hand with a black ring touches a white box. It is square on the bottom and has a sloped top. Various AC, 12V, and USB ports adorn its surface. It's approximately the size of a human head.

DIY Off Grid Battery Pack From EV Battery

Car camping gets you out in the great outdoors, but sometimes it’s nice to bring a few comforts from home. [Ed’s Garage] has taken a module from a salvaged EV and turned it into a handy portable power station.

With 2.3 kWh of storage from the single Spark EV module, the battery pack can power [Ed]’s hotplate, lights, fridge, and other electric accessories while camping away from shore power. The inverter he selected can provide up to 1500W of AC power and his 12V converter can do 150W. Several USB ports and a wireless charging pad adorn the outside next to the waterproof AC ports. He even printed a small magnetic flashlight to reuse the light from the inverter which uses an 18650 cell that can be charged from the big battery in a charger built into the exterior of the pack.

The battery management system (BMS) has a Bluetooth module allowing for remote monitoring of state of charge and setting the maximum and minimum charge points for the pack. The whole thing comes in at 73 pounds (33 kg), and while he had originally thought to give it wheels to roll, he changed his mind once he thought more about what sort of wheels he’d need to maneuver the thing in the backcountry.

If you’re thinking of building your own power pack, why not checkout a few other builds for inspiration like this one from tool batteries or one designed to charge directly from a solar panel. Be sure you checkout our guide on how to select a BMS if you’re going to use a lithium-based chemistry.

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Climate Change May Make Days Longer

For those who say there’s never enough time in a day, your wish for more time is getting granted, if ever so slightly. Scientists have now found a new source of our days getting longer — climate change.

You may have already been aware that the length of the day on Earth has been getting longer over time due to the drag exerted on our planet by our friendly neighborhood Moon. Many other factors come into play though, including the Earth’s own mass distribution. As the Earth warms and polar caps melt, the water redistributes to the Earth’s equator causing it to slow more rapidly.

In the worst-case scenario, RCP8.5, it would result in climate-related effects to planetary rotational velocity even larger than those caused by lunar tides. Under that scenario, the earth would probably be a less pleasant place to live in many other ways, but at least you’d have a little more time in your day.

While we’re talking about time, we wonder what ever happened to getting rid of Daylight Savings in the US? If you long for a simpler time, perhaps you should take up repairing mechanical watches and clocks?

A warehouse with concrete floors and at least four subway car rails running off into the distance. On the rails are dozens of R142 series subway cars with refurbished trucks in the foreground. People are visible on the floor moving a truck, and one man is in a bright yellow crane above everything watching what happens.

Overhauling Subway Cars Is A Big Job

Subway cars have a tough life. Moving people through a city efficiently underground every day and night takes a toll on the hardware. To keep things running efficiently, NYC rebuilds its cars every six years.

The enormous job of refurbing a subway car back to factory spec happens in one of two yards, either in Brooklyn or Manhattan. The cars are pulled off their 16,000 lb trucks, and treated to an overhaul of their “doors, windows, signage, seats, floor tiles and HVAC.” The trucks are inspected and wheels can be reground to true at the six year mark; they get all new wheels every 12.

Once everything is repaired, the shiny and like-new components are inspected and reassembled to go back out on the line. While it’s no small job, the overhaul shops can process over 1,000 cars in a year to keep things running smoothly. Before the overhaul program was introduced in the 1980s, NYC subway cars typically experienced failures every 16,000 miles, but between the scheduled maintenance and other advances that number has soared to an average failure rate every 140,000 miles.

For a somewhat less official use of underground spaces, how about this Parisian secret society? If you really want to bring the subway home, how about making an old subway seat into a chair? If you need something more light-hearted, you should really checkout this 90s subway safety video from LA.

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