Truly Giant Telescope Could Image Exoplanets

May 22, 2022 by 20 Comments

Have you ever wished we could peek at all these exoplanets that have been recently discovered? We aren’t likely to visit anytime soon, but it would be possible to build a truly giant telescope that could take a look at something like that. At least according to [SciShow Space] in a recent video you can see below.

The idea put forth in a recent scientific paper is to deliberately create the conditions that naturally form gravitational lenses. If you recall, scientists have used these naturally-occurring lenses to image the oldest star ever observed. These natural super-telescopes have paid off many times, but you can’t pick what you want to look at. It is all a function of the distance to the star creating the lens and the direction a line between us points.

But what if you could create your own gravity lens? Granted, we probably aren’t going to do that in our garages. However, a recent paper talks about launching an optical detector that you could maneuver so that it was on a line that would pass through the object you want to see and our own sun. We clearly have the technology to do this. After all, we have several nice space telescopes, and several probes operating far away from the sun.

That is one of the biggest catches, though. This new telescope will need to be some 550 AU from the sun to get good results. For the record, the Earth is 1 AU (about 8 light minutes) out. Pluto — maybe not a planet anymore, but still a signpost on the way out of the solar system — is a scant 39 AU out. Voyager I, which has been racing away from the sun since 1977 is only about 156 AU out.

Because the craft would be so far out, it would be practically a one-shot mission. You also have to have something reliable enough to go the 17 years it would take with today’s technology to get in place. You also need a way to get the data back over that distance. All doable, but non-trivial.

The paper simulates what the Earth would look like using this technique from a nearby star. The images are shockingly good, especially after a bit of post-processing. Meanwhile, we may have to settle for more modest images. You might not see detail, but it is possible to find exoplanets with reasonably modest equipment.

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Scott’s CPU From The Bottom Up

May 19, 2022 by 5 Comments

It isn’t for everyone, but if you work much with computers at a low level, you’ll probably sooner or later entertain the idea of creating your own CPU. There was a time when that was a giant undertaking, but with today’s tools and FPGAs it is… well, not easy, but certainly easier. If you have the urge to try your own, you might have a look at [Simply Explained’s] video series called “Building Scott’s CPU.”

The 11 videos cover everything from basic transistor logic to sequential circuits and moves on to things like ALUs, clock units, and how jump instructions work.

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3D Printed Linear Actuator Is Cheap And Strong

May 18, 2022 by 28 Comments

Motors are all well and good for moving things, but they’re all about the round-and-round. Sometimes, you need to move something back and forth, and for that a linear actuator will do the trick. While they can be readily sourced for under $50 online, [Michael Rechtin] genuinely felt like reinventing the wheel, and managed to whip up a 3D-printed design that costs under 20 bucks.

The basic design is simple, consisting of a small motor which is geared down through several stages using simple spur gears. The last gear in the train is tasked with turning a lead screw which drives the arm of the linear actuator back and forward.

For simplicity, [Michael] used a 24V brushed DC gearmotor for its low cost and the fact it already has a step-down gearbox integrated into the design. It’s paired with a couple more 3D-printed spur gears to provide even more torque. Instead of a fancy lead screw, the build instead just uses a quarter-inch bolt sourced from Home Depot, which can be had much cheaper. This pushes a 3D-printed arm back and forth thanks to a nut stuck in the arm. It’s all wrapped up in a neat-and-tidy 3D-printed housing. The design is able to push with a force of roughly 220 lbs. For a more practical idea of its strength, it can readily crush an empty soda can.

The video on the design is great, showing how important features like limit switches are added, and how the wiring can be neatly hidden away inside the housing. We’ve seen [Michael’s] work before, too, like strength testing various types of 3D printed gears. Video after the break.

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Book Teaches Gaming Math

May 17, 2022 by 13 Comments

If we knew how much math goes into writing a video game, we might have paid more attention in math class. If you need a refresher, [Fletcher Dunn] and [Ian Parbery] have their book “3D Math Primer for Graphics and Game Development” available free online. The book was originally a paper book from 2011 with a 2002 first edition but those are out of print now. However, math is math, so regardless of the age of the book, it is worth a look. For now, the online version is a bunch of web pages, but we hear a PDF or E-reader version is forthcoming.

There’s quite a bit of discussion about vectors, matrices, linear transformations, and 3D graphics. The last part of the book covers calculus, kinematics, and parametric curves. Some of these topics will be of interest even if you don’t care about graphics but do want to learn some math with practical examples.

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This Week In Security: F5 Twitter PoC, Certifried, And Cloudflare Pages Pwned

May 13, 2022 by 7 Comments

F5’s BIG-IP platform has a Remote Code Execution (RCE) vulnerability: CVE-2022-1388. This one is interesting, because a Proof of Concept (PoC) was quickly reverse engineered from the patch and released on Twitter, among other places.

HORIZON3.ai researcher [James Horseman] wrote an explainer that sums up the issue nicely. User authentication is handled by multiple layers, one being a Pluggable Authentication Modules (PAM) module, and the other internally in a Java class. In practice this means that if the PAM module sees an X-F5-Auth-Token, it passes the request on to the Java code, which then validates the token to confirm it as authentic. If a request arrives at the Java service without this header, and instead the X-Forwarded-Host header is set to localhost, the request is accepted without authentication. The F5 authentication scheme isn’t naive, and a request without the X-F5-Auth-Token header gets checked by PAM, and dropped if the authentication doesn’t check out.

So where is the wiggle room that allows for a bypass? Yet another HTTP header, the Connection header. Normally this one only comes in two varieties, Connection: close and Connection: keep-alive. Really, this header is a hint describing the connection between the client and the edge proxy, and the contents of the Connection header is the list of other headers to be removed by a proxy. It’s essentially the list of headers that only apply to the connection over the internet. Continue reading “This Week In Security: F5 Twitter PoC, Certifried, And Cloudflare Pages Pwned” →

3D printed fish leaping through waves

A Crazy Wave Automaton

May 8, 2022 by 9 Comments

[Henk Rijckhaert] recently participated in a “secret Santa” gift exchange. In a secret Santa, everyone’s name goes in a hat, and each person must pick a name without looking. Each gives a gift to the person whose name they drew.

Henk needed a gift for Amy, a friend who loves the water and water sports as well as maker-y things.  So he built her a wave automaton — a sea wave and fishies, and documented the build in this video.

The build is mostly plywood and 3D printed parts. We have to  think reprising it in a nice wood and brass would make a lovely project for a hobby wood and metalworker.

The bulk of the project is 30 plywood boards stacked up with spacers. Each board is mounted with a 3D printed stepped bushing on one end that rides in a horizontal slot. On the other end is a 3D printed eccentric riding in an oversized (about 5cm) hole. So the board moves in a circle at one end and back and forth at the other for a very nice simulation of an ocean wave. Continue reading “A Crazy Wave Automaton” →

Retrotechtacular: How Television Worked In The 1950s

May 6, 2022 by 29 Comments

Watching television today is a very different experience from that which our parents would have had at our age, where we have high-definition digital on-demand streaming services they had a small number of analogue channels serving linear scheduled broadcasting. A particular film coming on TV could be a major event that it was not uncommon for most of the population to have shared, and such simple things as a coffee advert could become part of our common cultural experience. Behind it all was a minor miracle of synchronised analogue technology taking the signal from studio to living room, and this is the subject of a 1952 Coronet film, Television: How It Works!  Sit back and enjoy a trip into a much simpler world in the video below the break.

Filming a TV advert: 1950s housewife sells cooker
Production values for adverts had yet to reach their zenith in the 1950s.

After an introduction showing the cultural impact of TV in early-50s America there’s a basic intro to a cathode-ray tube, followed by something that may be less familiar to many readers, the Image Orthicon camera tube that formed the basis of most TV signals of that era.

It’s written for the general public, so the scanning raster of a TV image is introduced through the back-and-forth of reading a book, and then translated into how the raster is painted on the screen with the deflection coils and the electron gun. It’s not overly simplified though, for it talks about how the picture is interlaced and shows how a synchronisation pulse is introduced to keep all parts of the system working together.

A particularly fascinating glimpse comes in a brief mention of the solid copper co-axial cable and overland microwave links used to transmit TV signals across country, these concrete towers can still be seen today but they no longer have the colossal horn antennas we can see in the film.

A rather obvious omission in this film is the lack of any mention of colour TV, as while it would be late 1953 before the NTSC standard was formally adopted and early 1954 before the first few colour sets would go on sale. Colour TV would have been very much the Next Big Thing in 1952, but with no transmissions to watch and a bitter standards war still raging between the field-sequential CBS system and RCA’s compatible dot-sequential system that would eventually evolve into the NTSC standard  it’s not surprising that colour TV was beyond the consumer audience of the time.

Thus we’re being introduced to the 525-line standard which many think of as NTSC video, but without the NTSC compatible colour system that most of us will be familiar with. The 525-line analogue standard might have disappeared from our living rooms some time ago, but as the last few stations only came off-air last year we’d say it had a pretty good run.

We like analogue TV a lot here at Hackaday, and this certainly isn’t the first time we’ve gone all 525-line. Meanwhile for a really deep dive into the inner workings of TV signal timing, get ready to know your video waveform.

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