Rockin’ Out In LTSpice: Simulating Classic Guitar Pedals

October 29, 2020 by 9 Comments

Musicians have a fantastic language to describe signals. A sound can be fat, dark, crunchy, punchy — the list goes on. These aren’t very technical terms, but they get the job done. After all, it’s much easier to ask to guitarist for a crisper sound than to ask them to sharpen the edges of the waveform, while amplifying the high-frequency components and attenuating the low-frequency components. Of course, it’s fun to look at signals this way as well, especially when you can correlate shifts in sound quality to changes in the waveform and, ideally, the circuit that produces it.

To undergo such an investigation, [Nash Reilly] has been simulating guitar effects pedals in LTSpice. Able to find most of the schematics he needs online, [Nash] breaks down the function of each part of the circuit and builds a simulation of the entire system. His write-up clearly explains, and often demonstrates, what’s going on inside the box. On the surface, it’s an interesting tour of the inner workings of your favorite effects pedals. Beyond that, it’s an excellent survey of analog design that is well-worth the read for anybody interested in audio, electronics, or audio electronics.

For those interested in taking the physical route rather than the simulated one, we’ve taken a look at pedal design before. Anybody who wants to try their hand at creating simulations can grab a copy of LTSpice, or check out a package called LiveSpice, which lets you simulate circuits in realtime and use them to process live audio — pretty useful for prototyping guitar effects.

DSL Is Barely Hanging On The Line As Telcos Stop Selling New Service

October 29, 2020 by 170 Comments

Are you reading this over AT&T DSL right now? If so, you might have to upgrade or go shopping for a new ISP soon. AT&T quietly stopped selling new traditional DSLs on October 1st, though they will continue to sell their upgraded fiber-to-the-node version. This leaves a gigantic digital divide, as only 28% of AT&T’s 21-state territory has been built out with full fiber to the home, and the company says they have done almost all of the fiber expansion that they intend to do. AT&T’s upgraded DSL offering is a fiber and copper hybrid, where fiber ends at the network node closest to the subscriber’s home, and the local loop is still over copper or coax.

At about the same time, a report came out written jointly by members of the Communications Workers of America union and a digital inclusion advocacy group. The report alleges that AT&T targets wealthy and non-rural areas for full fiber upgrades, leaving the rest of the country in the dark.

As the internet has been the glue holding these unprecedented times together, this news comes as a slap in the face to many rural customers who are trying to work, attend school, and see doctors over various videoconferencing services.

If you live in a big enough city, chances are you haven’t thought of DSL for about twenty years, if ever. It may surprise you to learn of the popularity of ADSL in the United Kindom. ADSL the main source of broadband in the UK until 2017, having been offset by the rise of fibre-to-the-cabinet (FTTC) connections. However, this Ofcom report shows that in 2018 ADSL still made up more than a third of all UK broadband connections.

Why do people still have it, and what are they supposed to do in the States when it dries up?

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Massive Battle Bot Needs Equally Chunky Custom-Molded Wheels

October 29, 2020 by 2 Comments

We’ve all run into situations where the right part for the job isn’t something that you can just buy off the shelf. In a lot of cases, 3D-printing is the cure for that problem, but sometimes you need to go big with tough parts for a tough job. These custom molded urethane battlebot wheels are a great example of that. (Video, embedded below.)

The robotic warrior in question is “Copperhead”, a heavyweight death-dealer that has competed on the “BattleBots” show on TV. It’s an incredibly stout machine with a ridiculous 50 pound (23 kg) drum of spinning tool-steel on the front to disassemble competitors. Add to that the sheer mass of the bot’s armor plating and running gear, throw in the need to withstand the punishment meted out by equally diabolical weapons, and standard wheels are not going to fly.

As [Robert Cowan] details in the video below, nothing but the sturdiest wheels will do, so the bot builders mold custom wheels with integrated hubs. The four-piece mold was machined out of aluminum to hold the plastic hubs, which were also machined but could easily have been 3D-printed. Polyurethane resin is poured in and adheres to the plastic hub better than we’d have thought it would: enough so to avoid coming apart despite some pretty severe blows. The whole casting process is a good watch, as is the overview of Copperhead’s design. And watching it tear apart “War Hawk” was a treat too.

You may not be building battle bots, but a scaled-down version of this process could be a handy trick to have stored away for someday. Continue reading “Massive Battle Bot Needs Equally Chunky Custom-Molded Wheels” →

DIY Regular Expressions

October 29, 2020 by 12 Comments

In the Star Wars universe, not everyone uses a lightsaber, and those who do wield them had to build them themselves. There’s something to be said about that strategy. Building a car or a radio is a great way to learn how those things work. That’s what [Low Level JavaScript] points out about regular expressions. Sure, a lot of people think they are scary. So why not write your own regular expression parser and engine? Get that under your belt and you’ll probably never fear another regular expression.

Of course, most of us probably won’t do it ourselves, but you can still watch the process in the video below. The code is surprisingly short, but don’t expect all the bells and whistles you might find in Python or even Perl.

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This Z80 Computer Bootstraps Itself

October 28, 2020 by 32 Comments

[Plasmode] has created several Z80-compatible board designs, at least four of them using the oddball Z280. The Z280 was a special variant of a Z80 that could bootstrap itself with no external PROM, making it ideal for anyone trying to build a system on a breadboard. According to his post, the cost to build the board is about $35.

Although the 8080 CPU got a lot of glory, it was much harder to use than the Zilog Z80. The Z80 only required a single clock and power supply, so it was much easier to build a system, even on a breadboard. On top of that, the bus wasn’t multiplexed and it could refresh DRAM memory by itself. Maybe that’s why you can still get Z80-derived chips readily. There was one thing, though, you needed an EPROM or some other way to run some initial code to bootstrap your system. Zilog knew this was a problem. In those days, you had to use a special tool to burn a PROM and, unless it was erasable and you had the special UV light to erase it, any mistakes cost you a chip.

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Projecting Halloween Peril

October 28, 2020 by 3 Comments

Every holiday has a few, dedicated individuals committed to “going all out.” Whether they’re trying to show up the neighbors, love the look, or just want to put a smile on the faces of those passing by; the results are often spectacular. A recent trend in decorations has been away from analog lights and ornaments and towards digital light shows via a projector. [Georgia Clegg] and [Luma Bakery] have written up a fantastic guide detailing the involved process of house projection for those feeling the holiday spirit.

There is more to the effect than simply pointing a projector at a home and running a video clip. The good displays make use of the geometry of the home and the various depths of the walls don’t distort the picture. The house itself is mapped into the image being displayed.

There are generally two approaches to mapping: point of view mapping and neutral/orthographic mapping. The first is just setting the projector in a fixed position and designing the graphics in such a way that they will look correct. The downside is that if there are multiple projectors, each projector will need to be separately designed for and they cannot be moved or adjusted. The second maps the house in an actual 3d sense and figures out how to display the content according to the viewpoint that the projector is currently at. This means you can create one source content and simply export it for the various projectors.

As you can imagine, the second is much more involved and this is where [Georgia Clegg] has stepped in. There’s a whole series that covers creating your house in MeshRoom, cleaning it up in Blender, creating the videos in After Effects, and setting up your projector to keep it running through the season.

We’ve seen other amazing projector mapping displays with lasers here at Hackaday. Now you can make one yourself. Just don’t get bogged down refurbishing your vector projector along the way.
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PyGame Celebrates 20 Years By Releasing PyGame 2.0

October 28, 2020 by 7 Comments

Python is an absolutely fantastic language for tossing bits of data around and gluing different software components together. But eventually you may find yourself looking to make a program with an output a bit more advanced than the print() statement. Once you’ve crossed into the land of graphical Python programming, you’ll quickly find that the PyGame library is often recommended as a great way to start pushing pixels even if you’re not strictly making a game.

Today, the project is celebrating an incredible milestone: 20 years of helping Python developers turn their ideas into reality. Started by [Pete Shinners] in 2000 as a way to interface with Simple DirectMedia Layer (SDL), the project was quickly picked up by the community and morphed into a portable 2D/3D graphics library that lets developers deploy their code on everything from Android phones to desktop computers.

Things haven’t always gone smoothly for the open source library, and for awhile development had stalled out. But the current team has been making great progress, and decided today’s anniversary was the perfect time to officially roll out PyGame 2.0. With more than 3,300 changes committed since the team started working on their 2.0 branch in July of 2018, it’s a bit tough to summarize what’s new. Suffice to say, the library is more capable than ever and is ready to tackle everything from simple 2D art up to 4K GPU-accelerated applications.

Rip and tear in PyGame 2.0

If you haven’t given PyGame a try in awhile, don’t worry. The team has put special effort into making the library as backwards compatible as possible, so if you’ve got an old project kicking around that you haven’t touched in a decade, it should still run against the latest and greatest version. If you’ve never used it before, the team says they’ll soon be releasing new tutorials that show you how to get the most out of this new release.

Whether you’re putting together your own implementation of Conway’s “Game of Life” or creating the graphical front-end for your own Linux distribution, PyGame is a powerful tool to have in your collection. Our sincere congratulations to all PyGame developers, past and present, for making it to this auspicious occasion. We can’t wait to see what the next decade will bring.

[Thanks to deshipu for the tip.]