Photographing Rocket Chute Deployment At 10 Km

April 22, 2026 by Bryan Cockfield No comments

For those who haven’t been following along, [BPS.space] aka [Joe] is on a journey to launch a home-built rocket past the Kármán line where it will officially reach outer space. But one does not simply launch a rocket to outer space on the first try. The process is long and involves not only building a series of rockets, but designing and building propellant mixtures, solving aerodynamic problems, gaining several model rocket certifications along the way, and a whole host of other steps. He’s also documenting the entire process on video as well, which involves some custom camera work like this rocket selfie camera which will take an image of his rockets at apogee.

Like most problems in high-power rocketry, extremely tiny problems have a way of causing catastrophic failure, so every detail needs to be considered and planned for in the final design. For a camera that needs to jettison itself from the rocket at a precise moment after experiencing an incredible amount of forces, this is a complicated problem to solve. The initial design involves building a sled for a small deconstructed GoPro which uses springs and a servo to launch itself out of the rocket. The major problem with the design is that even the smallest torque on the sled will cause the camera to point in a random direction by the time it’s far enough from the rocket to take a picture. [Joe] tried a number of design iterations but could not get these torques to vanish.

One of the design limitations with this camera is that it won’t have any sort of parachute or tether itself to the rocket, so it will hit the ground at its terminal velocity. To keep that velocity down and improve survivability chances of the footage, the mass has to stay low. Eventually he settled on a semi-active control system by mounting a brass weight on a small motor, giving the camera module enough stability to stay pointed at the rocket long enough to take the video. Even though it hasn’t flown yet, admitting his first design wasn’t working at compromising on this solution which adds a bit of mass seems to be a good design change. We’ve been following along with his entire process so be sure to check out his actual rocket motor builds and teardowns as well.

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New Display For Old Multimeter

April 14, 2026 by Bryan Cockfield 14 Comments

As a company, Fluke has been making electronic test equipment longer than the bipolar junction transistor has been around for. In that time they’ve developed a fairly stellar reputation for quality and consistency, but like any company they don’t support their products indefinitely. [ogdento] owns a Fluke meter that isn’t nearly as old as the BJT but still has an age well outside of the support window, and since the main problem was the broken LCD display they set about building a replacement for this retro multimeter.

Initially, [ogdento] had plans to retrofit this classic multimeter with a modern OLED, but could not find enough space for the display or a way to drive it easily. The next attempt to get something working was to build a custom one-off LCD using a drill press as an end mill, which didn’t work either. But after seeing a Charlieplexed display from [bobricius] as well as this video from EEVblog about designing custom LCDs, [ogdento] was able to not only design a custom PCB and LCD display to match the original meter, but was able to get a manufacturer in China to build them.

The new displays have a few improvements over the old; mostly they are more stylistically inspired by later Fluke models and have a few modern improvements to the LCD itself. There were are few issues during prototyping but nothing that was too hard to sort out, such as ordering the wrong size elastomeric strips initially. For anyone who needs to replace a custom LCD and can’t find replacement parts anymore, this project would be a great starting point for figuring out the process from the ground up.

The Joys Of 3D Printing

February 28, 2026 by Elliot Williams 45 Comments

Al and I were talking on the podcast today about a sweet 3D printed wide-format camera build, and we got to musing on why we 3D-print.

For Al, it’s an opportunity to experiment with 3D printing itself: tweaking his machines to get the best performance out of them. Other people make small, functional objects that they need in their daily life, like bag clips or spare parts for broken appliances. Some folks go for the ornamental or the aesthetic. The kids in my son’s class all seem obsessed with sci-fi props and fidget toys. The initial RepRap ideal was to replace all commercial fabrication with machines owned by the individual, rather than by companies – it was going to be Marxist revolutionary.

But there’s another group of 3D printer enthusiasts that I think doesn’t get enough coverage, and I’m going to call them the hobbyist industrial designers. These are the people who design a custom dog-poop-bag holder that exactly fits their extra-wide dog leash, not because they couldn’t find one that fit in the pet store, but because it’s simply fun to design and fabricate things. (OK, that’s literally me.)

It’s fun to learn CAD tools, to learn about how things are designed, how they work, and how to manufacture them at least in quantity one. Dreaming, designing, fabricating, failing, and repeating until you get it right is a great joy. And then you get to use the poop-bag holder every day for a few years, until you decide to refine the design and incorporate the lessons learned on the tough streets of practical use.

Of course none of this is exclusive to 3D printing. There were always people who designed-and-built things in the metal machine shop, or made their creations out of wood. In that sense, the 3D printer is just another tool, and the real fun isn’t in using the 3D printer, but rather in the process of bringing things out of your mind and into the world. So maybe there is nothing new here, but the latitude that 3D printing affords the hobby designer is amazing, and that makes it all the more fun, and challenging.

So do you 3D print for necessity, to stick it to the man, to pimp your printer, for the mini-figs, or simply for the joy of the process of making things? It’s all good. 3D printing is a big tent.

An Introduction To Analog Filtering

December 4, 2025 by Bryan Cockfield 8 Comments

One of the major difficulties in studying electricity, especially when compared to many other physical phenomena, is that it cannot be observed directly by human senses. We can manipulate it to perform various tasks and see its effects indirectly, like the ionized channels formed during lightning strikes or the resistive heating of objects, but its underlying behavior is largely hidden from view. Even mathematical descriptions can quickly become complex and counter-intuitive, obscured behind layers of math and theory. Still, [lcamtuf] has made some strides in demystifying aspects of electricity in this introduction to analog filters.

The discussion on analog filters looks at a few straightforward examples first. Starting with an resistor-capacitor (RC) filter, [lcamtuf] explains it by breaking its behavior down into steps of how the circuit behaves over time. Starting with a DC source and no load, and then removing the resistor to show just the behavior of a capacitor, shows the basics of this circuit from various perspectives. From there it moves into how it behaves when exposed to a sine wave instead of a DC source, which is key to understanding its behavior in arbitrary analog environments such as those involved in audio applications.

There’s some math underlying all of these explanations, of course, but it’s not overwhelming like a third-year electrical engineering course might be. For anyone looking to get into signal processing or even just building a really nice set of speakers for their home theater, this is an excellent primer. We’ve seen some other demonstrations of filtering data as well, like this one which demonstrates basic filtering using a microcontroller.

The Subtle Art Of Letterform Design

October 12, 2025 by Donald Papp 13 Comments

Typeface (such as Times New Roman) refers to the design that gives a set of letters, numbers, and symbols their signature “look”. Font, on the other hand, is a specific implementation of a typeface, for example, Times New Roman Italic 12 pt.

‘Q’ is a counterpoint to the idea that typography is just one fussy detail after another.

Right about this point, some of you are nodding along and perhaps thinking “oh, that’s interesting,” while the rest of you are already hovering over your browser’s Back button. If you’re one of the former, you may be interested in checking out the (sort of) interactive tour of typography design elements by the Ohno Type School, a small group that loves design.

On one hand, letters are simple and readily recognizable symbols. But at the same time, their simplicity puts a lot of weight on seemingly minor elements. Small changes can have a big visual impact. The tour lays bare answers to questions such as: What is the optimal parting of the cheeks of a capital ‘B’? At what height should the crossbar on an ‘A’ sit, and why does it look so weird if done incorrectly? And yet, the tail of a ‘Q’ can be just about anything? How and why does an ‘H’ define the spacing of the entire typeface? All these (and more) are laid bare.

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Personalization, Industrial Design, And Hacked Devices

July 26, 2025 by Elliot Williams 29 Comments

[Maya Posch] wrote up an insightful, and maybe a bit controversial, piece on the state of consumer goods design: The Death Of Industrial Design And The Era Of Dull Electronics. Her basic thesis is that the “form follows function” aesthetic has gone too far, and all of the functionally equivalent devices in our life now all look exactly the same. Take the cellphone, for example. They are all slabs of screen, with a tiny bezel if any. They are non-objects, meant to disappear, instead of showcases for cool industrial design.

Of course this is an extreme example, and the comments section went wild on this one. Why? Because we all want the things we build to be beautiful and functional, and that has always been in conflict. So even if you agree with [Maya] on the suppression of designed form in consumer goods, you have to admit that it’s not universal. For instance, none of our houses look alike, even though the purpose is exactly the same. (Ironically, architecture is the source of the form follows function fetish.) Cars are somewhere in between, and maybe the cellphone is the other end of the spectrum from architecture. There is plenty of room for form and function in this world.

But consider the smartphone case – the thing you’ve got around your phone right now. In a world where people have the ultimate homogeneous device in their pocket, one for which slimness is a prime selling point, nearly everyone has added a few millimeters of thickness to theirs, aftermarket, in the form of a decorative case. It’s ironically this horrendous sameness of every cell phone that makes us want to ornament them, even if that means sacrificing on the thickness specs.

Is this the same impetus that gave us the cyberdeck movement? The custom mechanical keyboard? All kinds of sweet hacks on consumer goods? The need to make things your own and personal is pretty much universal, and maybe even a better example of what we want out of nice design: a device that speaks to you directly because it represents your work.

Granted, buying a phone case isn’t necessarily creative in the same way as hacking a phone is, but it at least lets you exercise a bit of your own design impulse. And it frees the designers from having to make a super-personal choice like this for you. How about a “nothing” design that affords easy personalized ornamentation? Has the slab smartphone solved the form-versus-function fight after all?

Learn 15 Print-in-Place Mechanisms In 15 Minutes

May 11, 2025 by Dave Rowntree 4 Comments

3D printed in-place mechanisms and flexures, such as living hinges, are really neat when you can get them to print correctly. But how do you actually do that? YouTuber [Slant 3D] is here with a helpful video demonstrating the different kinds of springs and hinges (Video, embedded below) that can be printed reliably, and discusses some common pitfalls and areas to concentrate upon.

Living hinges are everywhere and have been used at least as long as humans have been around. The principle is simple enough; join two sections to move with a thinned section of material that, in small sections, is flexible enough to distort a few times without breaking off. The key section is “a few times”, as all materials will eventually fail due to overworking. However, if this thing is just a cheap plastic case around a low-cost product, that may not be a huge concern. The video shows a few ways to extend flexibility, such as spreading the bending load across multiple flexure elements to reduce the wear of individual parts, but that comes at the cost of compactness.

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