WebGPU… Better Than WebGL?

March 9, 2022 by 19 Comments

As the browser becomes more like an operating system, we are seeing more deep features being built into them. For example, you can now do a form of assembly language for the browser. Sophisticated graphics have been around using WebGL since around 2011, but some people find it hard to use. [Surma] was one of those people and tried a new method that is just surfacing to do the same thing: WebGPU.

[Surma] liked it better and shares a lot of information in the post and — oddly — the post doesn’t use WebGPU for graphics very much. Instead, the post focuses on using GPU cores for fast computation, something else you can do with WebGPU. If your goal is to draw on the screen, though, you need to know the basics and the post links to a site with examples of doing this.

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VFD Character Display Turned Into Audio VU Meter

March 9, 2022 by 8 Comments

Humans love visualising music, whether it’s in the form of an inscrutable equation drawing squiggles in Winamp, or a simple VU meter pulsing with the beat. This build from [mircemk] is of the latter variety, repurposing a VFD display to do the job.

The project is built around a VFM202MDA vacuum fluorescent display, which provides that lovely green-blue glow we all know and love, driven by a PT6314 driver chip. This has the benefit that it can be readily driven by a microcontroller in much the same way as the familiar HD44780 character LCD driver chip. With some minor tweaks, the character set can be modified to allow the display to become a surprisingly-responsive VU meter.

An Arduino Nano runs the show, with an envelope follower circuit feeding a signal for the left and right channels into the analog inputs of the microcontroller. The Arduino then measures the voltage on those inputs and feeds the necessary commands to the PT6314 driver to update the display.

The resulting VU meter has 38 bars per channel, and is highly responsive. The fast flickering of the meter bars in response to the music make it compelling to watch, and the era-appropriate enclosure the project is built in adds plenty to the aesthetic.

We’ve seen other VU meter builds before too, like this one that uses a little physics knowledge to create a more realistic analog-like needle meter. Video after the break.
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Building A Pendulum Clock Out Of Lego

March 9, 2022 by 10 Comments

Pendulum clocks aren’t used quite as often these days as their cumbersome mechanics and timekeeping abilities have long been outshone by electronic alternatives. However, they’re still fun and they do work, so [PuzzLEGO] set about building a working example with Lego.

The rear view reveals the escapement built from Lego Technic parts.

The core of the clock is the escapement, a linkage which the pendulum can only turn in one direction. As the pendulum swings once per second, it lets the escapement gear turn one notch forward at a time, turning the gears of the clock which drive the hands. It’s powered with a falling weight in the form of a drink bottle full of water, which turns the gears of the clock via a chain.

The clock can only run for approximately an hour, so it’s set up with a second and minute hand instead of the more usual minute and hour hand. However, with the pendulum tuned to the appropriate length and the weight fitted, it pleasantly ticks and tocks the seconds away.

We’ve seen other great builds from [PuzzLEGO] before, too, like this inventive Rubik’s Cube build. Video after the break.

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Class A Amplifiers, Virtually

March 9, 2022 by 21 Comments

If you didn’t know better, you might think the phrase “class A amplifier” was a marketing term to help sell amplifiers. But it is, of course, actually a technical description of an amplifier that doesn’t distort the input waveform because it doesn’t depend on multiple elements to handle different areas of the input waveform. Want to know more? [FesZ] has a new video covering the basics of class A amplifiers including some great simulations. You can see the video below.

A class A amplifier uses a transistor that is always biased on. It never saturates or switches off. This is good for linearity, but not always the best for efficiency so there are other classes of amplifiers, too. However, for many applications, class A is the most common configuration.

There are a number of trade-offs involved with each type of amplifier and [FesZ] covers them in detail. But the real interesting part is the simulations in Spice. Sure, you can build the circuits and look at everything with a meter or scope, but using Spice is much handier.

There is a second video upcoming. We hope he covers other amplifier types too, as you really do want to understand the differences when you need to design something. If you want more Spice stuff, check out some of our previous posts. If for some reason, you don’t like LTSpice, there’s always Micro-Cap 12.

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Cranes made by Origami (Orizuru). The height is 35mm.

Bringing The Art Of Origami And Kirigami To Robotics And Medical Technology

March 9, 2022 by 5 Comments

Traditionally, when it comes to high-tech self-assembling microscopic structures for use in medicine delivery, and refined, delicate grippers for robotics, there’s been a dearth of effective, economical options. While some options exist, they are rarely as effective as desired, with microscopic medicine delivery mechanisms, for example, not having the optimal porosity. Similarly, in so-called soft robotics, many compromises had to be made.

A promising technology here involves the manipulation of flat structures in a way that enables them to either auto-assemble into 3D structures, or to non-destructively transform into 3D structures with specific features such as grippers that might be useful in both micro- and macroscopic applications, including robotics.

Perhaps the most interesting part is how much of these technologies borrow from the Japanese art of origami, and the related kirigami.

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Upgraded 3D Printed Tank Gets Better Drivetrain And Controls

March 9, 2022 by 11 Comments

When it comes to 3D printed builds, they’re often limited in size due to the small build volume of most printers. However, [Ivan Miranda] has always gone big with his builds, and his latest tank design shows that off in spades.

Looks comfy!

[Ivan] has been working on printed human-sized tanks for years, and his latest revision aims to solve many of the problems that have hampered its performance in the past. A belt drive is the first major upgrade, aiming to improve the reliability of the drivetrain which has been a pain point in the past. The motor mounts also get built out of aluminium this time to help keep things cooler, as melting was a potential concern previously.

The tank’s controls are also upgraded, this time using a simple pedal system to control the brushless motors for easier driving. There’s even a printed seat for better ergonomics. The result is a giant tank big enough for an adult human, with the bonus that it’s now easy to steer and no longer requires [Ivan] to lie down inside to fit.

[Ivan’s] big printers are key to his success on big builds. One new part for the tank weighs a full 5.8 kg, printed in just 2.5 days! We can’t wait to see what giant thing he builds next. Word is the tank will be getting a turret, too. Video after the break.

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Raspberry Pi And The Story Of SD Card Corruption

March 9, 2022 by 107 Comments

Tales of Raspberry Pi SD card corruption are available online by the fistful, and are definitely a constant in Pi-adjacent communities. It’s apparent that some kind of problems tend to arise when a Raspberry Pi meets an SD card – which sounds quite ironic, since an SD card is the official and recommended way of booting a Pi. What is up with all of that?

I can start with a history lesson. Back when Raspberry Pi launched in 2012 – which is now 10 years ago – there were SD card controller driver problems, which makes sense given the wide variety of SD cards available out there. They were verifiably fixed one by one at some point in time, as debugging goes, their impact decreased and bugs with individual cards got smoothed over. This is how the “Pi SD card corruption” meme was originally born; however, if the problems were to end there, so would the meme. Yet, tales of broken SD cards plague us to this day – way less severe than they were in the beginning, but pronounced enough that you’ll see people encounter them every now and then.

Over the years, a devoted base of Pi SD card haters has grown. Their demand has been simple – Raspberry Pi has to get an ability to boot from something else, in large part because of corruption reasons, but also undeniably because of speed and capacity/cost limitations of SD cards. Thanks to their demands and work, we’ve seen a series of projects grow from unofficial efforts and hacks into officially supported Raspberry Pi abilities – USB boot being initially more of a workaround but now something you can enable out of the box, SSD-equipped Pi enclosures becoming more of a norm, and now, NVMe boot appearing on the horizon. Every few years, we get a new way to boot a Pi. Continue reading “Raspberry Pi And The Story Of SD Card Corruption” →