A Paddle Wheel Ground Effect Vehicle

January 25, 2024 by Danie Conradie 17 Comments

Who said paddle wheels were just for leisurely riverboat cruises? [rctestflight] is smashing that image with a high-speed twist on the concept, using paddle wheels to propel a ground effect vehicle across water. In the video after the break, witness this blend of old and new as he tests various designs.

Over the past few years he’s worked on a series of ground effect vehicles which exploits the increased lift and reduced drag when flying close to a surface. Unlike full-sized counterparts, smaller RC models struggle to stay in this sweet spot due to less pronounced self-stabilizing feedback loops. This means a small scale vehicle tends to touch the water rather often, and bleeding a lot of momentum in the process.

He wanted to convert these losses into gains by giving the vehicles a boost of speed whenever it touches the water. It’s a popular trick with RC cars which will hydroplane for long distances as long as they can maintain speed. All the designs still required air propellers for takeoff and to help maintain speed. The final design didn’t really need the paddle wheel when the air and water was calm, but it definitely helped when things got choppy. He is already experimenting with different paddle designs but also plans to test some other types of surface drives.

For covered a number off small scale ekranoplans, including a previous version by [rctestflight] that uses lidar for altitude control. He has also collaborated with [Think Flight] to build a autonomous small scale prototype for a maritime shipping startup.

Continue reading “A Paddle Wheel Ground Effect Vehicle” →

Steamboat Willie Never Sounded Better

January 24, 2024 by Al Williams 13 Comments

Mickey Mouse’s introduction to the world was the 1928 cartoon, Steamboat Willie. Not only was it the first appearance of Mickey with sound, it was also one of the first cartoons to employ synchronized sound. The problem is, the sound is awful. Sure, after nearly a century, what do you expect? But [Oona Räisänen] thought it wasn’t just age, but flutter from the original recording. Could it be made better? What follows that question is a self-described geek’s journey into the depths of recorded sound.

The first step was to find a high quality source. The Internet Archive had a copy that was mostly clean. But it also has a lossless scan of the movie including the original optical soundtrack. A quick script played back the original soundtrack and — you guessed it — the flutter is already there. You can see the original 7-minute short from Disney’s channel, below.

Continue reading “Steamboat Willie Never Sounded Better” →

Read QR Codes Without A Computer

January 22, 2024 by Al Williams 23 Comments

Did you ever watch Star Wars and wondered how people understood what R2D2 was saying? Maybe [Luke Skywalker] would enjoy learning to decode QR Codes by hand, too. While it might not be very practical, it would be a good party trick — assuming, like us, you party with nerds.

You can start by scanning a code, or the site will create one according to your specifications or generate one randomly. It then takes the selected code and shows you how it is put together. Fun fact: 21×21 “modules” (QR-speak for pixels) is the size of a version 1 QR code. Each version increases the size by four modules.

Continue reading “Read QR Codes Without A Computer” →

Predicting The A-Bomb: The Cartmill Affair

January 18, 2024 by Al Williams 18 Comments

The cover of the infamous issue of Astounding, March 1944

There’s an upcoming movie, Argylle, about an author whose spy novels are a little too accurate, and she becomes a target of a real-life spy game. We haven’t seen the movie, but it made us think of a similar espionage caper from 1944 involving science fiction author Cleve Cartmill. The whole thing played out in the pages of Astounding magazine (now Analog) and involved several other science fiction luminaries ranging from John W. Campbell to Isaac Asimov. It is a great story about how science is — well, science — and no amount of secrecy or legislation can hide it.

In 1943, Cartmill queried Campbell about the possibility of a story that would be known as “Deadline.” It wasn’t his first story, nor would it be his last. But it nearly put him in a Federal prison. Why? The story dealt with an atomic bomb.

Nothing New

By itself, that’s probably not a big deal. H.G. Wells wrote “The World Set Free” in 1914, where he predicted nuclear weapons. But in 1914, it wasn’t clear how that would work exactly. Wells mentioned “uranium and thorium” and wrote a reasonable account of the destructive power: Continue reading “Predicting The A-Bomb: The Cartmill Affair” →

Need A Refresher On RMS?

January 16, 2024 by Al Williams 21 Comments

If you mostly deal with DC current, you might not think much of root mean square or RMS measurements. Sure, you’ve seen meters that have “true RMS” settings, but what does it mean? If you don’t know — or you want a refresher — watch [Prof MAD’s] recent video explaining the topic.

There are two things to remember when working with RMS. If you put, say, 100VDC through a 100-ohm resistor, you’ll draw 1A and use 100W of power. However, since AC gradually makes its way to a peak value and then starts ramping down immediately, you can’t use the peak value or anything like it to figure out AC power. After all, the voltage is only at that peak for an instant. That’s where RMS comes in. 100 VAC RMS through a 100-ohm resistor will also consume an average of 100W over time.

Continue reading “Need A Refresher On RMS?” →

E-Ink Photo Frame Is A Simple, Pleasing Design

January 11, 2024 by Lewin Day 3 Comments

Regular photo frames are good, but they tend to only display a single photo unless you pull them to bits and swap out what’s inside. [Ben] decided to make a digital photo frame using an e-ink display to change things up, and unlike some commercial versions we’ve seen, it’s actually pretty tasteful!

The build is based on a Nook Simple Touch Reader, which can be had pretty cheaply on the used market. It was chosen for the fact it runs Android, which makes it comparatively easy to hack and customize compared to some other e-readers on the market. Once it’s running a custom Android brew, it can be set to run an app called Electric Sign which simply shows a given website fullscreen and updates it at regular intervals. That turns the Nook into a remotely updateable photo frame in one fell swoop. From there, it just took a little trickery to access an iCloud album to update the frame with fresh pics. Then [Ben] just had to customize a nice photo frame to neatly mount the e-reader with room for the cable to subtly snake out the back.

It’s a simple build that relies on some existing tools already laying around the Internet. That’s nice, because it makes it easy for anyone to replicate themselves at home given the same materials. We’ve seen some other great digital photo frames before, too. If you’ve built your own neat and creative way to display your pics, don’t hesitate to drop us a line!

19th Century Copy Machine: The Cyclostyle

January 10, 2024 by Al Williams 15 Comments

In the 2020s photocopiers are getting a bit exotic, although they are not gone yet. But these days, you are more likely to simply print multiple copies of a document. However, it wasn’t long ago that making a copy of a document was a tall order. Carbon paper was fine if you were typing and only needed a few copies. But in the late 1800s to early 1900s, several solutions were available, including a beautiful early mimeograph known as the Cyclostyle at [Our Own Devices], examined in the video below.

The Cyclostyle was possibly inspired by a hectograph (something we looked at before). The Cyclostyle was originally a special stylus used to remove wax from a paper stencil. Then, a process similar to screen printing would make copies for you.

Continue reading “19th Century Copy Machine: The Cyclostyle” →