Author: Al Williams

4499 Articles

Toxic Telescope Makes You Mad As A Hatter

January 25, 2023 by 51 Comments

[Hank Green] posted an interesting video about the first liquid mirror telescope from back in the 1850s. At the time, scientists were not impressed. But, these days, people are revisiting the idea. The big problem with the early telescope is that it used mercury. Mercury is really bad for people and the environment.

The good thing about a liquid scope is that you can pretty easily make a large mirror. You just need a shallow pool of liquid and a way to spin it. However, there are downsides. You need to isolate the liquid from vibrations and dust. Another downside is that since gravity makes the shape of the mirror, these telescopes only go one way — straight up.

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I’ve Been Printing On The Dragon Railroad…

January 25, 2023 by 28 Comments

We know many people who put much effort into building model train setups. But [Rambros] has an entire set 3D printed, and the files are open source, so you can print your own or modify it to suit you. When we first read “complete open source ecosystem,” we thought it might have been a bit of hyperbole, but it isn’t. The S-scale set includes two locomotives, a tanker, a box car, a hopper car, and a gondola car. There are different sections of track, customizable with Fusion 360. The “Dragon Railway” takes a few mechanical parts and electronics, of course. You can see one of several videos about the system below.

You can control the whole system using Bluetooth and a smartphone. The electronics are pretty simple, consisting of an ESP32 board, some motor drivers, N20 motors, and a few miscellaneous parts. We expect it would be compatible with other off-the-shelf S scale tracks and cars, but we don’t know that for sure.

Although you’ll need Fusion 360 to customize, there are plenty of ready-made STL files if you want to get started quickly. Some of the track items, like the crossing and turnout are not customizable, anyway. One particularly  impressive item is a printed auto-coupler; while a small item, getting that to work reliably with printed parts seems like it may be the most difficult part of the whole thing.

Maybe an OLED display would be the next thing? We’ve seen other printed trains, but this seems like a real labor of love.

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Old Ham Wisdom Leads To Better Aluminum Painting

January 24, 2023 by 50 Comments

When [bdk6] tried painting aluminum for electronic projects, he found it didn’t tend to stay painted. It would easily scratch off or, eventually, even flake off. The problem is the paint doesn’t want to adhere to the aluminum oxide coating around the metal. Research ensued, and he found an article in an old ham radio magazine about a technique that he could adapt to get good results painting aluminum.

Actually, paint apparently adheres poorly, even to non-oxidized aluminum. So the plan is to clean and remove as much aluminum oxide as possible. Then the process will convert the aluminum surface to something the paint sticks to better. Of course, you also need the right kind of paint.

The key ingredients are phosphoric acid and zinc phosphate. Phosphoric acid is found in soft drinks, but is also sold as a concrete and metal prep for painting. The zinc phosphate is part of a special paint known as a self-etching primer.

Cleaning takes soap, elbow grease, and sandpaper. The next step is a long soak in the phosphoric acid. Then you apply a few coats of self-etching primer and sand. Once it is all set, you can paint with your normal paint. That’s usually epoxy-based paint for [bdk6].

Of course, you can also dye aluminum while anodizing it. Soldering aluminum also has its challenges.

Bend It Like A Carpenter

January 24, 2023 by 18 Comments

We’ve always known, in theory, there are ways to bend wood, but weren’t really clear on how it worked. Now that we’ve seen [Totally Handy]’s recent video, we’ve learned a number of tricks to pull it off. Could we do any of them? Probably not, any more than watching someone solder under a microscope means you could do it yourself with no practice. But it sure made us want to try!

All of the techniques involve either water or steam, but we were fascinated with the cuts that make the wood almost into a flexible mesh. There are several tricks you can pick up, too, if you watch carefully. In “wordless workshop” form, there’s no real audio or text, just watching this guy make some really interesting wood pieces.

It looks like you could do some of this with pretty ordinary tools, although he does use a table saw, a router, and a few types of sanders. There isn’t anything too exotic, although we weren’t entirely clear on how the steam tube worked. If you have a cheap CNC machine, those usually can do a pretty good job on wood, and we wondered if you couldn’t pull off some of these tricks that way, too.

We love projects made with wood that look like they were impossible to make. Don’t forget wood as a construction material. Combined with 3D printing and other techniques, it can make some impressive things.

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Arduino Is Out To (Rocket) Launch

January 23, 2023 by 8 Comments

It looks like an ordinary toolbox, but when you open up the Arduino Launch Control System, you’ll find a safe method for triggering model rocket launches. The system uses two separate power supplies. Both must be on for a successful launch and one requires a key. To trigger a 10-second countdown, the operator must hold down two buttons. Releasing either button will stop the countdown.

Besides safety, the controller tracks mission elapsed time and can read weather information from a few sensors. A good-looking build and we like the idea of building inside a toolbox for this sort of thing.

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Listening To A Flashlight — Lunar Flashlight

January 23, 2023 by 4 Comments

If you’ve been looking for a practical example of using GNU Radio, you should check out [Daniel Estévez’s] work on decoding telemetry captured from the Lunar Flashlight cubesat. The cubesat is having some trouble, but the data in question was a recording from the day after launch. We aren’t sure what it would take to eavesdrop on it live, but the 3-minute recording is from a 20-meter antenna at 8.4 GHz.

The flowgraph for GNU Radio isn’t as bad as you might think, thanks to some judicious reuse of blocks from other projects to do some of the decoding. The modulation is PCM/PM/bi-phase-L. Nominally, the speed is supposed to be 48,000 baud, but [Daniel] measured 48,077.

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Smiling ad family with 3D printer

Ask Hackaday: Do Kids Need 3D Printers?

January 23, 2023 by 72 Comments

Mattel holds a fond place in most people’s hearts as they made many of the toys we played with as kids. You might remember the Thingmaker, which was essentially an Easy Bake Oven with some goop and molds that let you make rubbery creatures. But back in 2016, Mattel had an aborted attempt to bring 3D printing to kids under the Thingmaker label. You can see a promo video of the device below. You might not have seen one in real life, though. The product was delayed and eventually canceled. Even so, we frequently see press releases for “kids printers” and we’ve been wondering, should this be a thing? Continue reading “Ask Hackaday: Do Kids Need 3D Printers?” →