We had a comment recently from a nasty little troll (gasp! on the Internet!). The claim was that most makers are really just “copiers” because they’re not doing original work, whatever that would mean, but instead just re-making projects that other people have already done. People who print other peoples’ 3D models, or use other peoples’ hardware or software modules are necessarily not being creative. Debunking a cheap troll isn’t enough because, on deeper reflection, I’m guilty of the same generic sentiment; that feeling that copying other people’s work isn’t as worthy as making your own. And I think that’s wrong!

In the 3D printing world in particular, I’m guilty of dismissively classifying projects as “Yoda Heads”. About ten years ago, [chylld] uploaded a clean, high-res model of Yoda to Thingiverse, and everyone printed it out. Heck, my wife still has hers on her desk; and alone this is proof that straight-up copying has worth, because it made a sweet little gift. After a while, Yoda gave way to Baby Groots, and strangely enough we’re back to Yoda again, but it’s Baby Yoda now.

Does filling the world with more Yoda Heads, vomiting toothpaste or not, further creativity? I’d argue it does. It’s actually a moderately difficult print — those spindly little ears present an overhang challenge that’ll definitely help you calibrate your cooling, or force you to learn something about supports. Pushing your limits in 3D printing teaches you about the tool and what possibilities it presents. Mastering a tool is an important step toward using it creatively. And then there’s “riffing”.

Jazz musicians don’t just get up and play improvisational solos that come magically into their heads. They’ve spent hours in the shed, copying the ways that other players have interpreted the classics. Which is to say, they become creative through copying. Transcendental, inspirational, original moments come about through hours and hours of filtering other peoples’ work through your fingers, ears, and lips until it becomes a part of you and eventually bubbles up through your musical sensibility.

The same goes for any “derivative” project. We just covered a tuning-fork-based clock that was a remake of a previous incarnation, but in the process of re-making, it morphed a little bit into something more aesthetically post-apocalyptic. We’ve seen possibly a million word clock builds, but [t0mg]’s version this one is beautifully laser-etched into paint on the back side of glass, and made me think that you could do the same with the coating on the back side of a mirror. Riffing. I could go on for hours.

So maybe it’s not as sexy to re-make someone else’s project, but it can be tremendously valuable. It’s how we learn tools, how we increase our creative vocabulary, and it gives us a chance to explore something cool that someone else has done from the inside out. Copying should be seen as essential skill-building, despite our cultural prejudices against it. Go out and print yourself some Yoda Heads (metaphorically) without shame!

source https://hackaday.com/2021/02/27/printing-yoda-heads-re-makers-riffing/

Once a discarded relic, over the years the humble vacuum tube has been rehabilitated in the arena of specialist audio. There are plenty of tube amplifiers now being manufactured, with a popular choice being headphone amplifiers that use a tube as a gain stage followed by an op-amp as a buffer with a low impedance output. This forms the basis of [Ratti3]’s amplifier, but with the added interest of a battery supply and a Bluetooth connection.

The tube circuit is a very conventional anode follower using an EF95 pentode. This provides plenty of gain and of course that “valve sound” beloved of audio enthusiasts, but suffers from an output impedance too high to drive a set of headphones. An NE5532 steps in for the op-amp buffer role, making for a very simple circuit. Power comes from a set of four 18650 Lithium-Ion cells with associated charger and balance boards, while a little switching boost converter provides the 100 volt HT for the tubes.

We’ve visited this type of amplifier before with a similar but much more rough-around-the-edges Chinese version. That had some astonishingly cheap Chinese tubes, but if we’re seeking better components it’s interesting to know just who makes tubes these days.

source https://hackaday.com/2021/02/27/a-very-modern-tube-headphone-amplifier/

Here at Hackaday we’re no strangers to the colorful glow of LEDs. But what if there was more to appreciate beneath the surface? Back in 2011 [Windell] over at Evil Mad Scientist dug into a certain variety of LED and discovered they had a song to sing.

Over the last couple decades, you’ve likely encountered the flickering “candle flame” variety of LED. Often found embedded in small plastic candle simulacra they are shaped like typical through hole “gumdrop” style LEDs, but pack some extra magic which causes them to flicker erratically. Coupled with a warm white color temperature the effect isn’t entirely dissimilar to the flickering of a candle flame.

To the Hackaday reader (and [Windell]) the cause of the flickering may be fairly clear, there is an IC embedded in the lens of the LED. See photo at top for an example of how this might look, helpfully magnified by the lens of the LED itself. Looking through the lens the captive die is visible, as well as the bond wires connecting it to the legs and light emitting diode itself. [Windell]’s observation is that together this assembly makes for a somewhat strange electrical component; from the perspective of the circuit it appears to randomly vary the current flowing through the LED.

He includes two interesting demos. One is that by attaching the flickering LED to a BJT he can turn it into a current amplifier and successfully drive a much more powerful 1W LED with the same effect. The other is that  with the power of the amplifier the same flickering LED can drive a buzzer as well. The effect is surprisingly pleasant, though we’d hesitate to call it musical.

For a more recent example of a similar phenomenon with a very different sound, check out out [Emily Velasco]’s playback of a similarly constructed RGB color changing LED, embedded below. We’ve seen optical tools used to decode LED flickers into data streams, but not for audio playback! We have also covered some LED flicker reverse engineering that spills more of the mystery sealed up in these specialized diodes.

Did you ever wonder what a color-changing RGB LED sounds like?

I stuck one in the synthesizer to find out. pic.twitter.com/mjyrQIs7kk

— Emily Velasco (@MLE_Online) February 24, 2021

source https://hackaday.com/2021/02/27/sounding-the-humble-led/

You know those bottle fillers at schools and airports? What if you had one of those at home?

We know what you’re going to say: “My fridge has one of those!” Well ours doesn’t, and even though [Chris Courses’] fridge did, his bottle of choice didn’t fit in the vertically-challenged water and ice hutch, nor did it fill autonomously. The solution was to build a dubiously placed, but nonetheless awesome custom bottle filler in his kitchen.

The plumbing for the project couldn’t be more straight-forward: a 5-year undersink water filter, electronically actuated valve, some tubing, and a T to splice into the existing water line going to the fridge. Where the rubber hits the road is making this look nice. [Chris] spends a lot of time printing face plates, pouring resin as a diffuser, and post processing. After failing on one formulation of resin, the second achieves a nice look, and the unit is heavily sanded, filled, painted, prayed over, and given the green light for installation.

For the electronics [Chris] went for a Raspberry Pi to monitor four buttons and dispense a precise allotment tailored to each of his favorite drinking vessels. While the dispenser is at work, three rows of LEDs play an animated pattern. Where we begin to scratch our heads is the demo below which shows there is no drain or drip tray below the dispenser — seems like an accident waiting to happen.

Our remaining questions are about automating the top-off process. At first blush you might wonder why a sensor wasn’t included to shut off the filler automatically. But how would that work? The dispenser needs to establish the height of the bottle and that’s a non-trivial task, perhaps best accomplished with computer vision or a CCD line sensor. How would you do it?

source https://hackaday.com/2021/02/26/bottle-filler-perfectly-tops-your-cup/

You know those bottle fillers at schools and airports? What if you had one of those at home?

We know what you’re going to say: “My fridge has one of those!” Well ours doesn’t, and even though [Chris Courses’] fridge did, his bottle of choice didn’t fit in the vertically-challenged water and ice hutch, nor did it fill autonomously. The solution was to build a dubiously placed, but nonetheless awesome custom bottle filler in his kitchen.

The plumbing for the project couldn’t be more straight-forward: a 5-year undersink water filter, electronically actuated valve, some tubing, and a T to splice into the existing water line going to the fridge. Where the rubber hits the road is making this look nice. [Chris] spends a lot of time printing face plates, pouring resin as a diffuser, and post processing. After failing on one formulation of resin, the second achieves a nice look, and the unit is heavily sanded, filled, painted, prayed over, and given the green light for installation.

For the electronics [Chris] went for a Raspberry Pi to monitor four buttons and dispense a precise allotment tailored to each of his favorite drinking vessels. While the dispenser is at work, three rows of LEDs play an animated pattern. Where we begin to scratch our heads is the demo below which shows there is no drain or drip tray below the dispenser — seems like an accident waiting to happen.

Our remaining questions are about automating the top-off process. At first blush you might wonder why a sensor wasn’t included to shut off the filler automatically. But how would that work? The dispenser needs to establish the height of the bottle and that’s a non-trivial task, perhaps best accomplished with computer vision or a CCD line sensor. How would you do it?

source https://hackaday.com/2021/02/26/bottle-filler-perfectly-tops-your-cup/

If you are a certain age, your first programming language was almost certainly BASIC. You probably at least saw the famous book by Ahl, titled BASIC Computer Games or 1010 BASIC Computer Games. The book, published in 1973 by [David Ahl] was a staple in its day and the first computer book to sell over one million copies. Of course, if you want to run Super Star Trek or Hamurabi, you better fire up an old retrocomputer or a simulator because BASIC in 1973 doesn’t look like what we have today. Or, you can head to GitHub where [coding-horror] is inviting people to help update the programs using modern languages.

One of our favorites, Bagels, is there with directories for C#, Java, Javascript, Python, Ruby, and VB.net. It doesn’t appear that all of the games are in all the languages, though. There’s also a .Net solution file that apparently has a few entries in it. We were also happy to see Super Star Trek represented, along with a link to an article about a C++ language port. The original games were tweaked to run on VintageBasic.

By today’s standards, these games are pretty crude, but they are still engaging and, if you remember them, always nostalgic.  There is one thing missing, though. In 1973, you had no choice but to type the programs in yourself. You couldn’t help but learn something about programming in the process. Besides, you then had to debug the program to find your typing mistakes and that was definitely educational. It might seem like these games are ultra-simple, but hexapawn does machine learning and the lunar lander game is a simple physics simulation.

Regardless of language, if I were using these with a student, I might be tempted to make them type the programs in by hand. They’d probably revolt against the idea, but it might be good training. Think of “wax on, wax off” from the Karate Kid.

Seeing some of these old gems is like unexpectedly running into an old friend. If you want to help out, there’s a discussion board available. You’d think BASIC would be gone by now, but it still hangs in there. If your program is short enough, you might even run it on Twitter.

source https://hackaday.com/2021/02/26/the-famous-basic-computer-games-book-gets-a-2021-update/

A few machines have truly changed the world, such as the wheel, steam engines, or the printing press. Maybe 3D printers will be on that list one day too. But for today, you can use your 3D printer to produce a working printing press by following plans from [Ian Mackay]. The machine, Hi-Bred, allows you to place printed blocks in a chase — that’s the technical term — run a brayer laden with ink over the type blocks and hand press a piece of paper with the platen.

The idea is more or less like a giant rubber stamp. As [Ian] points out, one way to think about it is that white pixels are 0mm high and black pixels are 3mm high. He suggests looking at old woodcuts for inspiration.

This might be just the thing for doing something fancy like custom invitations. Seems like it would be pretty hard to do a booklet or magazine, although anything is possible if you are patient. Real type was made with lead and we doubt the plastic type will be quite as durable.

Of course, if you just want the old school feel, you could try a mimeograph or hectograph. In the old days, typesetter put type in from big cases that often wind up now as shadowboxes. But then came the Linotype.

source https://hackaday.com/2021/02/26/3d-printed-printing-press-turns-you-into-gutenberg/

It probably can’t have taken long after the first spectrum waterfall display was created, before somebody had a go at creating a waveform that would create an image in the waterfall. We don’t know who that pioneer was, but it’s over 20 years since Aphex Twin famously used the technique in their music, so it’s nothing new. If you fancy a go for yourself, [Gokberk Yaltirakli] has the project for you, creating waterfall images with an SDR from image files, using a bit of Python code.

The value here isn’t necessarily in creating the waterfall of Bitcoin logos that can be seen in the video he’s put on the page, instead it’s in the simple explanation of creating I and Q values for an SDR. The code is a bit slow so writes its values to a file which is output by a HackRF, but it could just as easily be used by any other capable output device such as GNU Radio and a soundcard if you too want an Aphex Twin moment. The hardware for displaying a spectrum waterfall doesn’t even have to be very complex.

Thanks [Leo] for the tip.

source https://hackaday.com/2021/02/26/spectrogram-drawing-for-fun-and-coding/

There’s a new malware strain targeting MacOS, Silver Sparrow, and it’s unusual for a couple reasons. First, it’s one of the few pieces of malware that targets the new M1 ARM64 processors. Just a reminder, that is Apple’s new in-house silicon design. It’s unusual for a second reason — it’s not doing anything. More precisely, while researchers have been watching, the command and control infrastructure didn’t provide a payload. Silver Sparrow has been positively found on nearly 30,000 machines.

The malware also has an intentional kill switch, where the presence of a particular file triggers a complete removal of the malware package. Researchers at Red Canary point out that this package behaves very much like a legitimate program, difficult to pick out as malware. Ars Technica got an off-the-record statement from Apple, indicating that they are tracking the situation, and have revoked the developer’s certificate used to sign the malware. It’s not entirely clear whether this prevents the malware running on already compromised machines, or just stops new infections.

So who’s behind Silver Sparrow? The observed stealth mode and other complexities suggest that this is more than a simple adware or ransomware campaign. Since it was discovered before the payload was delivered, we may never know what the purpose is. It may have been a government created campaign, targeting something specific.

VMware RCE

The details of a VMware vulnerability were published this week, and the attack struck me as rather elegant. CVE-2021-21972 is a combination of two problems. The first is that the VMware web interface exposes an HTTP endpoint that doesn’t enforce user authentication. One of the functions of this endpoint is to allow the upload of an archive file, and extract this in the /tmp directory. The second problem is that the extraction function didn’t properly sanitize the names of the extracted files. Hence, it was possible to create an archive with a path transversal attack.

Here we have two very simple flaws, and when put together, allow a completely unauthenticated actor to easily get arbitrary code execution on the machine running VMware. The attack works on Linux and Windows servers, with expected implementation variations.

Inside a Wireless Security System

Ever wonder just how secure a residential security system is? [Nick Miles] and [Chris Lyne], a pair of researchers from Tenable, wondered the same thing, and decided to tear apart a SimpliSafe system, wringing out all of its secrets. They started with logic analyzers, and went as far as paying for functional decapping of the chips, to recover the firmware.

The step-by-step process is worth reading, but the conclusion is that the system is relatively well put together. Each device has an immutable AES key, and that represents an attack surface that wouldn’t be present with a more robust key exchange.

For the curious, [Nick] did a detailed analysis of a Ring system just a few months back.

Proper Exploit Attribution, The Story of Jian

I’ve been known to be a bit skeptical when an attack or exploit is attributed to a foreign nation, but no real evidence is presented. A story caught my eye this week, because it’s a wonderful example of what proper attribution looks like, not to mention a great example of unraveling a malware mystery. Check Point Research looked deep into an exploit used by APT31, believed to be a part of the Chinese government.

There are way too many details to dive into here, go read the post for the particulars, but we’ll cover the high points. Remember the Shadow Brokers leak, back in 2017? That was a collection of impressive 0-days that is universally recognized as produced by the Equation Group, part of the NSA. One of the tools exposed in that lead was “EpMe”, which leveraged CVE-2017-0005. Jian, an exploit produced by APT31 also targeted this CVE, and was probably created in 2014.

The kicker here is that Checkpoint makes a very convincing case that it was no accident that both exploits targeted the same CVE, but that the Chinese exploit was based on a captured sample of the NSA-produced tool. Essentially, they reverse-engineered the exploit and used it in their own operations, even before the tool was exposed by the Shadow Brokers.

Firefox State Partitioning

Mozilla has released a new privacy feature, State Partitioning, a way to authoritatively stop cookie-based tracking online. The concept is deceptively simple. Every domain you visit has its own “cookie jar”. Many websites have Facebook iframes or embedded images. State partitioning would isolate the cookies created by each of those iframes, meaning your browser is anonymous to Facebook on each of those sites.

Hand-in-hand is a new API that allows a website to request cross-site cookie access. This is important for the handful of uses where access is needed for legitimate uses, like Single Sign-On services. For now, partitioning is off by default, and can be turned on via the Enhanced Tracking Protection strict setting.

JSON Undefined Behavior

[Jake Miller] of Bishop Fox Labs wrote a great intro to a subject I’ve never considered: odd JSON constructions, and how different implementations handle them. An example will help.

obj = {"test": 1, "test": 2}

So what’s the value of obj["test"]? It’s complicated. Some JSON parsers will choose the first definition of a key, while others choose the last. Still others will throw an error in response. What makes this a particularly serious problem is that the same data may be parsed by different implementations in a single transaction. The example given in the post is of an online store, where the payment processing is handled by a third party.

The attack works by manipulating the JSON object sent by the browser, injecting a second value definition for the quantity of items purchased. The store itself sees the higher value, which determines the actual items shipped. The payment backend uses a different JSON parser, which sees the smaller value. The backend actually handles payment processing, so the amount charged is that of the smaller quantity.

The article goes on to describe issues with invalid unicode embedded in JSON and valid keypairs that have been /*commented out*/, and what happens when you re-serialize this quirky data. Another interesting edge case is the handling of very large numbers, where some parsers return 0, others return a null, and some an approximation in scientific notation.

All told, JSON deserialization is a mess. There’s sure to be many hard-to-spot bugs in web applications that use multiple parsers. The author makes a few recommendations at the end of the post. The most important is that parsers should produce a fatal error on particular quirky JSON input, rather than returning a guess at what data was intended.

source https://hackaday.com/2021/02/26/this-week-in-security-mysterious-mac-malware-an-elegant-vmware-rce-and-a-json-mess/

When it comes to dominating offroad performance, many people’s first thought is of tracked vehicles. Bulldozers, tanks and excavators all use treads, and manage to get around in difficult terrain without breaking a sweat. Today, we’re exploring just what makes tracked vehicles so capable, as well as their weaknesses.

It’s All About Ground Pressure

Let’s first look at how tank tracks work. There are a huge variety of designs, with differences depending on application. Different trends have been followed over time, and designs for military use in combat differ from those used for low-speed construction machines, for example. But by looking at a basic tank track design, we can understand the basic theory. On tanks, the track or tread itself is usually made up of individual steel links that are connected together with hinges, though other machines may use rubber tracks instead. The tracks are wrapped around one or more drive wheels, often cogged, which directly pull on the track. On the bottom of the vehicle are the road wheels, which ride on top of the track where it lies on the ground.  The weight of the vehicle is carried through the road wheels and passed on to the tread, spreading out the load across a broader area. Outside of this, the track system may also have one or more idler wheels used to keep the track taught, as well as return rollers to guide the track back around without touching the road wheels.

Tank tracks, or continuous tracks as they’re more technically known, were developed initially for farm and logging applications, for heavy vehicles that needed to operate in soft terrain. Continuous treads had the advantage that they could support a vehicle’s weight over a much greater area than wheels. Spreading out the load meant that the ground pressure was lower, and thus the vehicle was less likely to sink into soft mud or sand. It also allowed a vehicle to put much more torque to the ground without slipping, thanks to the much larger contact patch compared to regular wheels. The party piece of the tank — the ability to crush smaller road vehicles — is as much a result of its huge weight as its tracks. However, the tracks are less likely to get tangled or damaged when driving over another vehicle, compared to a pneumatic tyre.

Awful Highway Mileage

However, tracks come with drawbacks that make them unsuitable for many applications. There’s a reason you don’t see tanks taking people to work on the New Jersey Turnpike; if you did you’d probably assume something political had gone very, very wrong. For many vehicular applications, the simple pneumatic tyre and wheel combination is more suitable. Pneumatic tyres do less damage to paved surfaces than tracks, and are better suited to higher speed operation. They’re also less noisy, and far easier to replace when damaged. Tracks are significantly more mechanically complicated, with the average tank having many more wheels and moving parts, as well as the tracks themselves. All of these add some loss to the driveline, making tracked transport far less fuel efficient, too. Steering on tracked vehicles can also be complicated for single-engine setups, requiring special gear mechanisms to allow the speed of each tread to be varied appropriately. Additionally, while tracks are great on soft surfaces, they don’t offer anything particularly special when it comes to ground clearance. In many cases, a properly designed wheeled vehicle may out perform a tracked one in a rock-crawling scenario.

Tracks as a Drive Train

Tracks are also used on smaller scale vehicles, from robots to radio controlled toys. Here, they maintain the benefits of lower ground pressure compared to wheels. However, the often lower weight of smaller scale vehicles means this isn’t as much of a benefit as it is for a main battle tank that must carry up to 60 tons of armour and weaponry into battle. Smaller scale vehicles that run on electricity can have the benefit of running one motor per track however, eliminating much of the steering complexity in single-engine vehicles. Much like larger vehicles, while tracks may offer better performance in soft surfaces, ground clearance is still important for dealing with obstacles like rocks.

Overall, it’s important to remember that tracks were designed to do one thing well, and that’s get vehicles through soft, boggy terrain like mud, snow and sand. If you’re having to deal with such conditions, the tank track might be just the engineering solution you’ve been looking for. If, however, high speed, efficiency, or comfort are more important – you’re probably best sticking with wheels!

source https://hackaday.com/2021/02/26/should-i-use-wheels-or-tracks/

When it comes to dominating offroad performance, many people’s first thought is of tracked vehicles. Bulldozers, tanks and excavators all use treads, and manage to get around in difficult terrain without breaking a sweat. Today, we’re exploring just what makes tracked vehicles so capable, as well as their weaknesses.

It’s All About Ground Pressure

Let’s first look at how tank tracks work. There are a huge variety of designs, with differences depending on application. Different trends have been followed over time, and designs for military use in combat differ from those used for low-speed construction machines, for example. But by looking at a basic tank track design, we can understand the basic theory. On tanks, the track or tread itself is usually made up of individual steel links that are connected together with hinges, though other machines may use rubber tracks instead. The tracks are wrapped around one or more drive wheels, often cogged, which directly pull on the track. On the bottom of the vehicle are the road wheels, which ride on top of the track where it lies on the ground.  The weight of the vehicle is carried through the road wheels and passed on to the tread, spreading out the load across a broader area. Outside of this, the track system may also have one or more idler wheels used to keep the track taught, as well as return rollers to guide the track back around without touching the road wheels.

Tank tracks, or continuous tracks as they’re more technically known, were developed initially for farm and logging applications, for heavy vehicles that needed to operate in soft terrain. Continuous treads had the advantage that they could support a vehicle’s weight over a much greater area than wheels. Spreading out the load meant that the ground pressure was lower, and thus the vehicle was less likely to sink into soft mud or sand. It also allowed a vehicle to put much more torque to the ground without slipping, thanks to the much larger contact patch compared to regular wheels. The party piece of the tank — the ability to crush smaller road vehicles — is as much a result of its huge weight as its tracks. However, the tracks are less likely to get tangled or damaged when driving over another vehicle, compared to a pneumatic tyre.

Awful Highway Mileage

However, tracks come with drawbacks that make them unsuitable for many applications. There’s a reason you don’t see tanks taking people to work on the New Jersey Turnpike; if you did you’d probably assume something political had gone very, very wrong. For many vehicular applications, the simple pneumatic tyre and wheel combination is more suitable. Pneumatic tyres do less damage to paved surfaces than tracks, and are better suited to higher speed operation. They’re also less noisy, and far easier to replace when damaged. Tracks are significantly more mechanically complicated, with the average tank having many more wheels and moving parts, as well as the tracks themselves. All of these add some loss to the driveline, making tracked transport far less fuel efficient, too. Steering on tracked vehicles can also be complicated for single-engine setups, requiring special gear mechanisms to allow the speed of each tread to be varied appropriately. Additionally, while tracks are great on soft surfaces, they don’t offer anything particularly special when it comes to ground clearance. In many cases, a properly designed wheeled vehicle may out perform a tracked one in a rock-crawling scenario.

Tracks as a Drive Train

Tracks are also used on smaller scale vehicles, from robots to radio controlled toys. Here, they maintain the benefits of lower ground pressure compared to wheels. However, the often lower weight of smaller scale vehicles means this isn’t as much of a benefit as it is for a main battle tank that must carry up to 60 tons of armour and weaponry into battle. Smaller scale vehicles that run on electricity can have the benefit of running one motor per track however, eliminating much of the steering complexity in single-engine vehicles. Much like larger vehicles, while tracks may offer better performance in soft surfaces, ground clearance is still important for dealing with obstacles like rocks.

Overall, it’s important to remember that tracks were designed to do one thing well, and that’s get vehicles through soft, boggy terrain like mud, snow and sand. If you’re having to deal with such conditions, the tank track might be just the engineering solution you’ve been looking for. If, however, high speed, efficiency, or comfort are more important – you’re probably best sticking with wheels!

source https://hackaday.com/2021/02/26/should-i-use-wheels-or-tracks/

When it comes to dominating offroad performance, many people’s first thought is of tracked vehicles. Bulldozers, tanks and excavators all use treads, and manage to get around in difficult terrain without breaking a sweat. Today, we’re exploring just what makes tracked vehicles so capable, as well as their weaknesses.

It’s All About Ground Pressure

Let’s first look at how tank tracks work. There are a huge variety of designs, with differences depending on application. Different trends have been followed over time, and designs for military use in combat differ from those used for low-speed construction machines, for example. But by looking at a basic tank track design, we can understand the basic theory. On tanks, the track or tread itself is usually made up of individual steel links that are connected together with hinges, though other machines may use rubber tracks instead. The tracks are wrapped around one or more drive wheels, often cogged, which directly pull on the track. On the bottom of the vehicle are the road wheels, which ride on top of the track where it lies on the ground.  The weight of the vehicle is carried through the road wheels and passed on to the tread, spreading out the load across a broader area. Outside of this, the track system may also have one or more idler wheels used to keep the track taught, as well as return rollers to guide the track back around without touching the road wheels.

Tank tracks, or continuous tracks as they’re more technically known, were developed initially for farm and logging applications, for heavy vehicles that needed to operate in soft terrain. Continuous treads had the advantage that they could support a vehicle’s weight over a much greater area than wheels. Spreading out the load meant that the ground pressure was lower, and thus the vehicle was less likely to sink into soft mud or sand. It also allowed a vehicle to put much more torque to the ground without slipping, thanks to the much larger contact patch compared to regular wheels. The party piece of the tank — the ability to crush smaller road vehicles — is as much a result of its huge weight as its tracks. However, the tracks are less likely to get tangled or damaged when driving over another vehicle, compared to a pneumatic tyre.

Awful Highway Mileage

However, tracks come with drawbacks that make them unsuitable for many applications. There’s a reason you don’t see tanks taking people to work on the New Jersey Turnpike; if you did you’d probably assume something political had gone very, very wrong. For many vehicular applications, the simple pneumatic tyre and wheel combination is more suitable. Pneumatic tyres do less damage to paved surfaces than tracks, and are better suited to higher speed operation. They’re also less noisy, and far easier to replace when damaged. Tracks are significantly more mechanically complicated, with the average tank having many more wheels and moving parts, as well as the tracks themselves. All of these add some loss to the driveline, making tracked transport far less fuel efficient, too. Steering on tracked vehicles can also be complicated for single-engine setups, requiring special gear mechanisms to allow the speed of each tread to be varied appropriately. Additionally, while tracks are great on soft surfaces, they don’t offer anything particularly special when it comes to ground clearance. In many cases, a properly designed wheeled vehicle may out perform a tracked one in a rock-crawling scenario.

Tracks as a Drive Train

Tracks are also used on smaller scale vehicles, from robots to radio controlled toys. Here, they maintain the benefits of lower ground pressure compared to wheels. However, the often lower weight of smaller scale vehicles means this isn’t as much of a benefit as it is for a main battle tank that must carry up to 60 tons of armour and weaponry into battle. Smaller scale vehicles that run on electricity can have the benefit of running one motor per track however, eliminating much of the steering complexity in single-engine vehicles. Much like larger vehicles, while tracks may offer better performance in soft surfaces, ground clearance is still important for dealing with obstacles like rocks.

Overall, it’s important to remember that tracks were designed to do one thing well, and that’s get vehicles through soft, boggy terrain like mud, snow and sand. If you’re having to deal with such conditions, the tank track might be just the engineering solution you’ve been looking for. If, however, high speed, efficiency, or comfort are more important – you’re probably best sticking with wheels!

source https://hackaday.com/2021/02/26/should-i-use-wheels-or-tracks/

By now most readers should be used to addressable LEDs, devices that when strung out in a connected chain can be individually lit or extinguished by a serial data stream. Should you peer at one under a microscope you’ll see alongside the LED dies an integrated circuit that handles all the address decoding. It’s likely to be quite a complex device, but how simply can its functions be replicated? It’s a theme [Tim] has explored in the TransistorPixel, and addressable LED board that achieves addressability with only 17 transistors.

It uses a surprisingly straightforward protocol, in which a pulse longer than 500ns enables the LED while a shorter one turns it off. Subsequent pulses in a train are passed on down the line to the next device. A 20µs absence of a pulse resets the string and sets it to wait for the next pulse train. Unlike the commercial addressable LEDS there is only a single colour and no suport for gradated brightness, but it’s still an impressive circuit.

Under the hood is some very old-school RTL logic, a monostable to detect the pulse and a selection of gates and a latch to capture the state and forward to the chain. It’s laid out on a PCB in order of circuit function, and while we can see that maybe it’s not a practical addresssable LED for 2021, it’s likely that it could be made into a much smaller PCB if desired.

Perhaps unsurprisingly given the ready availability of addressable LEDs, we’ve not seen many home made ones. This addressable 7-segment display may be the closest.

source https://hackaday.com/2021/02/26/diy-all-transistor-addressable-pixel/

We won’t pretend to fully grok everything going on with this open-source 8.5-digit voltmeter that [Marco Reps] built. After all, the design came from the wizards at CERN, the European Organization for Nuclear Research, home to the Large Hadron Collider and other implements of Big Science. But we will admit to finding the level of this build quality absolutely gobsmacking, and totally worth watching the video for.

As [Marco] relates, an upcoming experiment at CERN will demand a large number of precision voltmeters, the expense of which led to a homebrew design that was released on the Open Hardware Repository. “Homebrew” perhaps undersells the build a bit, though. The design calls for a consistent thermal environment for the ADC, so there’s a mezzanine level on the board with an intricately designed Peltier thermal control system, including a custom-machined heat spreader blocker. There’s also a fascinatingly complex PCB dedicated solely to provide a solid ground between the analog input connector — itself a work of electromechanical art — and the chassis ground.

The real gem of this whole build, though, is the vapor-phase reflow soldering technique [Marco] used. Rather than a more-typical infrared process, vapor-phase reflow uses a perfluropolyether (PFPE) solution with a well-defined boiling point. PCBs suspended above a bath of heated PFPE get bathed in inert vapors at a specific temperature. [Marco]’s somewhat janky setup worked almost perfectly — just a few tombstones and bridges to fix. It’s a great technique to keep in mind for that special build.

The last [Marco Reps] video we featured was a teardown of a powerful fiber laser. It’s good to see a metrology build like this one, though, and we have a feeling we’ll be going over the details for a long time.

source https://hackaday.com/2021/02/26/homebrew-metrology-the-cern-way/

We’ve seen a lot of coffee roaster builds over the years. [Ben Eagan] started his with a hot-air popcorn maker. If you think it is as simple as putting beans in place of the popcorn, think again. You need to have good control of the heat, and that requires some temperature monitoring and a controller — in this case, an Arduino. [Ben’s] video below shows how it all goes together.

With the Arduino and the power supply strapped to the sides, it looks a bit like something out of a bad post-apocalypse movie. But it looks like it gets the job done.

In addition to the Arduino, a thermocouple measures the temperature and that takes a little circuitry in the form of a MAX31855. There’s also a relay to turn the heater on and off. There are other ways to control AC power, of course, and if a relay offends your sensibilities you can always opt for a solid state one.

The only other wrinkle was the addition of an extra power supply so the fan could operate without the heater. There might have been some other ways to manage that, but power supplies are cheap enough and at least the strapped on power supply counterbalances the strapped on Arduino on the other side of the popper.

We’ve seen popcorn poppers used like this before, of course. Thermocouples are a great way to measure high temperatures, but there are lots of other ways to measure that particular quantity.

source https://hackaday.com/2021/02/25/tired-of-popcorn-roast-coffee-instead/

David Letterman made the top ten list famous. [Creel] has a top ten that should appeal to many Hackaday readers: the top 10 craziest x86 assembly language instructions. You have to admit that the percentage of assembly language programmers is decreasing every year, so this isn’t going to have mass appeal, but if you are interested in assembly or CPU architecture, this is a fun way to kill 15 minutes.

Some would say that all x86 instructions are crazy, especially if you are accustomed to reduced instruction set computers. The x86, like other non-RISC processors, has everything but the kitchen sink. Some of these instructions might help you get that last 10 nanoseconds shaved off a time-critical loop.

There are also interesting instructions like RDSEED, which generates a real random number. That can be useful but it takes many clock cycles to run, and like anything that purports to generate random numbers, is subject to a lot of controversies.

Our favorite, though, was PSHUFB. As soon as we saw “Mr. Mojo Risin’!” as the example input string, we knew where it was going. You could probably go a lifetime without using any of these instructions. But if you need them, now you’ll know.

If you really want to learn modern assembly language, there’s plenty of help. We occasionally write a little Linux assembly, just to keep in practice.

source https://hackaday.com/2021/02/25/oddball-x86-instructions/

Marvelously conceived and exquisitely executed, this huge ball made up of hexagon tiles combines the best of blinky LEDs and animatronics into one amorphic ball.

The creation of [Nicholas Perillo] of Augmentl along with [MindBuffer], full details of the “morph v2” project have not yet been published. However, some tantilizing build progress is documented on [Nicholas’] Insta — most especially through the snapshots in the story thread spanning the last seven months. The scope of the project is brought into focus with time lapse video of hundreds of heat-set inserts, bundles of twisted wire, a pile of 1500 sliding rails, cases full of custom-order stepper motors, and thick cuts of copper bus bars to feed power up the shaft and out to the panels.

The demo video after the break is mesmerizing, shot by [nburdy] during a demo at MotionLab Berlin where it was built. Each hex tile is backed by numerous LEDs and a stepper motor assembly that lets it move in and out from the center of the ball. Somehow it manages to look as though it’s flowing, as they eye doesn’t pick up spaces opening between tiles as they are extended.

The Twitter thread fills in some of the juicy details: “486 stepper motors, 86,000 LEDs and a 5 channel granular synth engine (written by @_hobson_ no less, in @rustlang of course).” The build also includes speakers mounted in the core of the ball, hidden behind the moving LED hexes. The result is an artistic assault on reality, as the highly coordinated combinations of light, sound, and motion make this feel alive, otherwordly, or simply a glitch in the matrix. Watching the renders of what animations will look like, then seeing it on the real thing drives home the point that practical effects can still snap us out of our 21st-century computer-generated graphics trance.

It’s relatively easy to throw thousands of LEDs into a project these days, as PCBA just applies robots to the manufacturing problem. But motion remains a huge challenge beyond a handful of moving parts. But the Times Square billboard from a few years ago and the Morph ball both show it’s worth it.

As you’ve guessed from the name, this is the second Morph ball the team has collaborated on. Check out details of v1, a beach ball sized moving LED ball.

486 stepper motors, 86,000 LEDs and a 5 channel granular synth engine (written by @_hobson_ no less, in @rustlang of course). pic.twitter.com/Sn2fp5tuXc

— nburdy (@nburdy) February 12, 2021

source https://hackaday.com/2021/02/25/morph-led-ball-is-a-there-is-no-spoon-reality-bending-art-installation/

Marvelously conceived and exquisitely executed, this huge ball made up of hexagon tiles combines the best of blinky LEDs and animatronics into one amorphic ball.

The creation of [Nicholas Perillo] of Augmentl along with [MindBuffer], full details of the “morph v2” project have not yet been published. However, some tantilizing build progress is documented on [Nicholas’] Insta — most especially through the snapshots in the story thread spanning the last seven months. The scope of the project is brought into focus with time lapse video of hundreds of heat-set inserts, bundles of twisted wire, a pile of 1500 sliding rails, cases full of custom-order stepper motors, and thick cuts of copper bus bars to feed power up the shaft and out to the panels.

The demo video after the break is mesmerizing, shot by [nburdy] during a demo at MotionLab Berlin where it was built. Each hex tile is backed by numerous LEDs and a stepper motor assembly that lets it move in and out from the center of the ball. Somehow it manages to look as though it’s flowing, as they eye doesn’t pick up spaces opening between tiles as they are extended.

The Twitter thread fills in some of the juicy details: “486 stepper motors, 86,000 LEDs and a 5 channel granular synth engine (written by @_hobson_ no less, in @rustlang of course).” The build also includes speakers mounted in the core of the ball, hidden behind the moving LED hexes. The result is an artistic assault on reality, as the highly coordinated combinations of light, sound, and motion make this feel alive, otherwordly, or simply a glitch in the matrix. Watching the renders of what animations will look like, then seeing it on the real thing drives home the point that practical effects can still snap us out of our 21st-century computer-generated graphics trance.

It’s relatively easy to throw thousands of LEDs into a project these days, as PCBA just applies robots to the manufacturing problem. But motion remains a huge challenge beyond a handful of moving parts. But the Times Square billboard from a few years ago and the Morph ball both show it’s worth it.

As you’ve guessed from the name, this is the second Morph ball the team has collaborated on. Check out details of v1, a beach ball sized moving LED ball.

486 stepper motors, 86,000 LEDs and a 5 channel granular synth engine (written by @_hobson_ no less, in @rustlang of course). pic.twitter.com/Sn2fp5tuXc

— nburdy (@nburdy) February 12, 2021

source https://hackaday.com/2021/02/25/morph-led-ball-is-a-there-is-no-spoon-reality-bending-art-installation/

Marvelously conceived and exquisitely executed, this huge ball made up of hexagon tiles combines the best of blinky LEDs and animatronics into one amorphic ball.

The creation of [Nicholas Perillo] of Augmentl along with [MindBuffer], full details of the “morph v2” project have not yet been published. However, some tantilizing build progress is documented on [Nicholas’] Insta — most especially through the snapshots in the story thread spanning the last seven months. The scope of the project is brought into focus with time lapse video of hundreds of heat-set inserts, bundles of twisted wire, a pile of 1500 sliding rails, cases full of custom-order stepper motors, and thick cuts of copper bus bars to feed power up the shaft and out to the panels.

The demo video after the break is mesmerizing, shot by [nburdy] during a demo at MotionLab Berlin where it was built. Each hex tile is backed by numerous LEDs and a stepper motor assembly that lets it move in and out from the center of the ball. Somehow it manages to look as though it’s flowing, as they eye doesn’t pick up spaces opening between tiles as they are extended.

The Twitter thread fills in some of the juicy details: “486 stepper motors, 86,000 LEDs and a 5 channel granular synth engine (written by @_hobson_ no less, in @rustlang of course).” The build also includes speakers mounted in the core of the ball, hidden behind the moving LED hexes. The result is an artistic assault on reality, as the highly coordinated combinations of light, sound, and motion make this feel alive, otherwordly, or simply a glitch in the matrix. Watching the renders of what animations will look like, then seeing it on the real thing drives home the point that practical effects can still snap us out of our 21st-century computer-generated graphics trance.

It’s relatively easy to throw thousands of LEDs into a project these days, as PCBA just applies robots to the manufacturing problem. But motion remains a huge challenge beyond a handful of moving parts. But the Times Square billboard from a few years ago and the Morph ball both show it’s worth it.

As you’ve guessed from the name, this is the second Morph ball the team has collaborated on. Check out details of v1, a beach ball sized moving LED ball.

486 stepper motors, 86,000 LEDs and a 5 channel granular synth engine (written by @_hobson_ no less, in @rustlang of course). pic.twitter.com/Sn2fp5tuXc

— nburdy (@nburdy) February 12, 2021

source https://hackaday.com/2021/02/25/morph-led-ball-is-a-there-is-no-spoon-reality-bending-art-installation/

Even with all the technological progress civilization has made, weather and seasons still have a major impact on our lives. [John de Hosson] owns a cabin on an island in a Swedish lake, and reaching it involves crossing 500 m of water. In summer this is done with a conventional boat, and in winter they can simply walk across the thick ice, but neither of these is an option on thin ice in the spring or fall. To solve this [John] built an electric airboat, and it looks like a ton of fun in the video after the break

The construction is simple but functional. A 3.3 m flat-bottomed aluminum boat has used a base, and an aluminum frame was bolted on for the motor and propeller. The motor is an 18 kW brushless motor, with a 160 cm/63-inch carbon fiber propeller. Power comes via a 1000 A ESC from a 100V 3.7 kWh Lipo pack mounted in a plastic box. Steering is very similar to a normal airboat, with a pair of air rudders behind the propeller, controlled by a steering lever next to the driver’s seat. The throttle is an RC controller with the receiver wired to the ESC.

Performance is excellent, and it accelerates well on ice and slush, even with two people on board. [John] still plans to make several improvements, with a full safety cage around the propeller being at the top of the list. He is also concerned that it will capsize on the water with the narrow hull, so a wider hull is planned. [John] has already bought a large steering servo to allow full remote control for moving cargo, with the addition of an FPV system. We would also add an emergency kill switch and waterproofing for the electronics to the list of upgrades. It looks as though the battery box is already removable, which is perfect for getting it out of the cold when not in use.

Even the small scale are boats are a fun RC project which can be built from only junk bin parts, or you can go to the other extreme and add full autonomous navigation.

Thanks for the tip [Måns Almered]!

source https://hackaday.com/2021/02/25/electric-airboat-for-getting-you-across-thin-ice/

2020 and all its ills have claimed another stalwart among PC builders and electronics hobbyists: Fry’s announced yesterday that they have closed up shop for good after nearly 36 years in business both as a brick-and-mortar wonderland and an online mecca for all things electronic.

According to Fry’s website (PDF copy for posterity), all 31 stores across nine states were suddenly and permanently shuttered on Wednesday the 24th, citing changes in the retail industry and the widespread difficulties wrought by the pandemic. Signs of the retailer’s growing challenges were seen back in 2019 when the company began shifting toward a consignment model in an attempt to cut overhead and liability.

Sadly, I never set foot inside of a Fry’s though I hear it was an experience beginning with the themed entrances found at many of the locations. Now it seems I never will. Where I live, Microcenter is king, and it has been truly awesome to watch the hobby electronics section expand from a single four-foot panel in a dark corner to the multi-aisle marketplace it is today. I keep imagining that Microcenter suddenly went out of business instead, and it makes me want to cry.

So where can a person go to pick up some quick components now that Radio Shack and Fry’s are no more? Of course there’s the previously mentioned Microcenter, but you should also look for old-school supply stores in your area. They may not have an Adafruit section and they’re probably not open after 5:00PM or on the weekends, but these stores are still kicking and they need us now more than ever. We’ve previously reported on gems like Tanner’s Electronics which sadly closed its doors almost a year ago. Help spread the word about your favorites that are still open in the comments below.

Thank you [Ryan], [John], and [Jack] for tipping us off.

[Main image source: San Jose Fry’s by Bryce Edwards; CC-BY 2.0]

source https://hackaday.com/2021/02/25/frys-electronics-has-fizzled-out-completely/

2020 and all its ills have claimed another stalwart among PC builders and electronics hobbyists: Fry’s announced yesterday that they have closed up shop for good after nearly 36 years in business both as a brick-and-mortar wonderland and an online mecca for all things electronic.

According to Fry’s website (PDF copy for posterity), all 31 stores across nine states were suddenly and permanently shuttered on Wednesday the 24th, citing changes in the retail industry and the widespread difficulties wrought by the pandemic. Signs of the retailer’s growing challenges were seen back in 2019 when the company began shifting toward a consignment model in an attempt to cut overhead and liability.

Sadly, I never set foot inside of a Fry’s though I hear it was an experience beginning with the themed entrances found at many of the locations. Now it seems I never will. Where I live, Microcenter is king, and it has been truly awesome to watch the hobby electronics section expand from a single four-foot panel in a dark corner to the multi-aisle marketplace it is today. I keep imagining that Microcenter suddenly went out of business instead, and it makes me want to cry.

So where can a person go to pick up some quick components now that Radio Shack and Fry’s are no more? Of course there’s the previously mentioned Microcenter, but you should also look for old-school supply stores in your area. They may not have an Adafruit section and they’re probably not open after 5:00PM or on the weekends, but these stores are still kicking and they need us now more than ever. We’ve previously reported on gems like Tanner’s Electronics which sadly closed its doors almost a year ago. Help spread the word about your favorites that are still open in the comments below.

Thank you [Ryan], [John], and [Jack] for tipping us off.

[Main image source: San Jose Fry’s by Bryce Edwards; CC-BY 2.0]

source https://hackaday.com/2021/02/25/frys-electronics-has-fizzled-out-completely/

In a sad but unsurprising turn of events, MCH, this summer’s large hacker camp in the Netherlands, has been cancelled. Organising a large event in a pandemic would inevitably carry some risk, and despite optimism that the European vaccine strategy might have delivered a safe environment by the summer that risk was evidently too high for the event organisers IFCAT to take on. Our community’s events come from within the community itself rather than from commercial promoters, and the financial liability of committing to hire the site and infrastructure would have been too high to bear had the event succumbed to the pandemic. Tickets already purchased will be refunded, and they leave us with a crumb of solace by promising that alternatives will be considered. We understand their decision, and thank them for trying.

As with all such events the behind-the-scenes work for MCH has already started. The badge has been revealed in prototype form, the call for participation has been completed, and the various other event team planning will no doubt be well  under way. This work is unlikely to be wasted, and we hope that it will bear fruit at the next Dutch event whenever that may be.

It would have been nice to think that by now we could be seeing the light at the end of the pandemic tunnel, but despite the sterling work of scientists, healthcare workers, and epidemiologists, it seems we still have a a way to go before we’ll once more be hanging out together drinking Club-Mate in the company of thousands of others. If the pandemic is weighing upon you, take care of yourselves.

source https://hackaday.com/2021/02/25/may-no-longer-contain-hackers-mch-2021-has-been-cancelled/

When you make something, what does version one look like? What I mean is, how much thought do you put into the design? Do you try to make it look nice as you go along, or do you just build something that functions and say screw the presentation? Do you try to solve for everything upfront, or just plow through it and promise to fix your mistakes in version two? What if you never make version two?

No matter what you like to make, there’s a first time for everything. And it doesn’t seem to matter if you need the thing you’re making or just want to have it around: it’s a given that version one will probably be a bit rough around the edges. That’s just how it goes. Even if you’re well-versed in a skill, when you try a new type of project or a new pattern, it will be a new experience. For example, I’ve sewn a dozen different purses, but when I took on a new challenge I found I was only somewhat prepared to make my first backpack.

Great is the enemy of good, and perfection is the enemy of progress. Shooting for a pristine prototype on the first go steep and rocky path that never leads to finishing the build. So our goal here is to decide what makes rev1 good enough that we still love it, even if rev2 never happens.

Want vs. Need

Of course, the answers to all of the opening questions greatly depend on want versus need. When I’m making something for fun, I’m happiest while I’m still inside the project. I want it to be over so I can see the finished product, but I also don’t want the process of making it to end, because that’s the fun part. It’s like reading a really good book. With sewing projects, I’m always really excited to see how they come together. It seems like no matter how I manipulate fabric beforehand and try to visualize how something will turn out, the end result is always a little bit of a surprise.

If I need the thing I’m making, I’m more likely to work quickly and cut corners to get the thing into use. The trouble with that is if I don’t spend enough time in the design phase, I’ll probably end up annoyed at the very least, or back to square one without a viable solution. In either case, I’ll admit that I have a pretty serious case of perfectionism. It affects everything I do. I love and hate this part of myself in equal amounts, because I’ve made some things I feel fairly proud of. But I’m usually too hard on myself along the way. If I were any harder on myself, I would probably never start or finish anything. Try to reign that in by setting expectations in the design phase, with plenty of thought spent on how you’ll achieve each needed feature.

Case in Point: The Practice Backpack

At the beginning of this year, I decided to make a backpack and document the process. I had made exactly one backpack before this one, but the designs differ enough that I decided to make a practice backpack first out of fabric I already have. This way, I can go through the pattern once and work out the kinks before buying fancy, expensive fabric — something I didn’t do with the first backpack and somewhat regret. In dressmaking, this is called making a muslin. It’s somewhat akin to a circuit made on stripboard: a functional prototype that’s more permanent than a breadboarded circuit. It may not be pretty, but it works. Ideally.

It’s not that I needed a backpack, I just wanted to practice bag-making, because I learn something from every new pattern I try. Even so, I knew I didn’t want to make any old thing. This is where my personal design conundrum begins. Yes, this is something I want to do rather than something I need to do. But I still have to consider how much time and money I’ll be investing in making the thing. I didn’t keep a clock running this time, but I would estimate that it took at least ten to fifteen solid hours of my free time. Shouldn’t I make it as pretty as possible?

Another thing to consider is that the end product will be a backpack, a real, functional backpack. This is not a breadboarded version of a backpack full of safety pins and/or hot glue. I will be using real fabric, working zippers, and actual webbing for the handles and straps. It doesn’t have to be perfect, sure. But shouldn’t it lean toward making me proud rather than embarrassed? I say yes. Because I might want to use it, or even sell it to someone else if it turns out well enough. So this practice backpack required plenty of decisions up front, from the fabric to the zippers to the hardware.

Decisions, Decisions

First and foremost was choosing the fabrics. Fabric is expensive in general, so instead of buying new fabric, I took a long, hard look at my stash — my parts bin if you will. The more bag-making I do, the more that everything looks like usable fabric to me, especially big things like table cloths and decorative shower curtains. A few years ago, I bought an off-white canvas drop cloth to use as a photography backdrop. It has since been wadded up and forgotten, so I threw it in the wash, thrilled with the idea of sewing a bunch of bags with what feels like free fabric.

This project is a lined backpack, so it calls for an exterior fabric and an interior fabric. The first pastry-pocked backpack I made, the tiny purse-sized one, uses the same fabric inside and out — a thin quilting cotton like standard bed sheet material. In order to make it suitable for a bag, it all had to be interfaced.

Interfacing is a material that’s applied as a backing to any fabric that needs more body. I’m exaggerating a little, but you can make anything out of anything if you have the right interfacing. Think of it like a veneered cabinet door: the fabric you want to show is the veneer, and the interfacing is what lies underneath, giving it the strength and structure it needs to pass as a cabinet door. In the case of the doughnuts backpack, the exterior pieces have two types of interfacing — woven first, and then foam. The backpack is empty in the pictures above; it’s the foam interfacing that gives it all that shape.

For the lining, I turned back to the fabric stash. I have several yards of a geometric-patterned quilting cotton in a southwestern/earth-toned color palette that I think looks really good next to the drop cloth canvas. At some point early on in the project, I decided to use lining fabric for the exterior side pockets to add visual interest.

Generally speaking, the heavier a fabric is, the less interfacing you need to strengthen it. The drop cloth I used is made of a lightweight canvas, so it has enough body that I didn’t have to interface it all. (Avoiding the use of interfacing is my new favorite thing, because that stuff is stupidly expensive.) On the other hand, the lining material I used is like bed sheets — too floppy to use by itself without interfacing, even in the lining.

Zippers vs. Zipper Tape

For both backpacks, the first step is making the zippered cargo pocket on the front, so I knew I had to make my zipper decisions early on.

This backpack has four zippers total: one 24″ zipper with two kissing zipper pulls for the main opening, an 11″ zipper for the front patch pocket, and two 8″ zippers, one for the exterior pocket above the patch pocket, and one for the interior pocket.

Here’s the thing about zippers: buying single, pre-made zippers gets expensive fast. Although it’s certainly not easier to do it this way, it is much more economical to buy a few yards of zipper tape and some pulls and make them myself. Plus, now I have some extra black zipper tape and pulls in my stash for the next bag.

Webbing, Handles, and Hardware

This pattern calls for ladder lock buckles, which are your standard backpack strap adjuster thingies. Standard as they may be, I didn’t have a single one on hand — only metal hardware. Much like the zippers, they are cheaper in bulk, so now I have 48 more ladder lock buckles to use in 24 more backpacks.

It’s the same with the polypropylene webbing that makes up the handles and the adjustable part of the straps. The backpack would probably look better if I found some in a fun color that matches the interior fabric, but this is version one. It’s cheaper and far more practical to buy several yards of black webbing, because black goes with almost everything. I did already have some webbing, but it’s the wrong size for the pattern. Now I have it in two sizes.

Enter the Project Conundrum

Bag-making is just like anything else — it takes materials, tools, time, and effort. I tell myself it’s cheaper in the long run to buy hardware and other things in bulk, because I’ll have them around to make more bags. I used to think that I wanted to make my own clothes, but bag-making is much more fun and practical, especially when it comes to selling them.

The problem is I now have a fully functional backpack that I merely like and don’t love because of my material decisions. I’ll be honest — I don’t know if I’ll ever make version two of this backpack. I probably will if I come across the right fabric because I don’t have any other square backpacks. I’m glad I put thought and effort into version one, but there are some things I would do differently, like adding foam padding for the laptop-sized pocket. Now that I know how it goes together, I would probably add more pockets, or maybe even hack the pattern and change the size.

So, if I had made those different decisions from the start, would I be strapping on my beloved backpack as my daily driver, or would I never have gotten the thing off the ground in the first place? That’s a tough line to walk.

And You?

So, how about you? How much effort do you put into version one of any given project? Does it really matter, as long as you finish it and move on? That question is probably worth a think piece of its own.

source https://hackaday.com/2021/02/25/what-if-i-never-make-version-two/

What have you been doing to ward off the winter blues? [TechnoChic] decided to lean in to winter and make a really fun-looking game out of it by combining the awesome PinBox 3000 cardboard pinball sandbox with a couple of Micro:bits to handle and display the player’s score. Check it out the build and gameplay in the video after the break.

The story of Planet Winter is a bittersweet tale: basically, a bunch of penguins got tired of climate change and left Earth en masse for a penguin paradise where it’s a winter wonderland all year round. There’s a party igloo with disco lights and everything.

[TechnoChic] used a Micro:bit plugged into a Brown Dog Gadgets board to keep track of scoring, control the servo that kicks the ball back out of the igloo, and run the blinkenlights. It sends score updates over Bluetooth to a second Micro:bit and a Pimoroni Scrollbit display that sit opposite the pinball launcher. She went through a few switch iterations before settling on conductive maker tape and isolating the ball so it only contacts the tape tracks.

There are two ways to score on Planet Winter — the blizzard at the end of the ball launcher path nets you ten points, and getting the ball in the party igloo is good for thirty. Be careful on the icy lake in the middle of the playfield, because if the ball falls through the ice, it’s gone for good, along with your points. It’s okay, though, because both the party igloo and the ice hole trigger an avalanche which releases another ball.

Seriously, these PinBox 3000 kits are probably the most fun you can have with cardboard, even fresh out of the box. They are super fun even if you only build the kit and make a bunch of temporary targets to test gameplay, but never settle on a theme (ask us how we know). Not convinced? Hackaday Editor-in-Chief [Mike Szczys] explored them in depth at Maker Faire in 2018.

source https://hackaday.com/2021/02/24/microbit-makes-cardboard-pinball-more-legit/