Author: Bryan Cockfield

1851 Articles

Ferrofluid Dances In Custom Bluetooth Speaker

April 21, 2021 by 12 Comments

Ferrofluids, as the name implies, are liquids that respond to magnetic fields. They were originally developed for use by NASA as rocket fuel but are available to the general public now for anyone who wants to enjoy their unique properties. For [Dakd Jung], that meant building a special chamber into a Bluetooth speaker that causes the ferrofluid inside to dance along with the rhythm of the music.

This project isn’t quite as simple as pushing the ferrofluid container against a speaker, though. A special electromagnetic device similar to a speaker was used specifically to manipulate the fluid, using a MSGEQ7 equalizer to provide the device with only a specific range of frequencies best tailored for the fluid’s movement. The project includes two speakers for playing the actual music that point upward, and everything is housed inside of a 3D-printed case. There were some additional hurdles to overcome as well, like learning that the glass needed a special treatment to keep the ferrofluid from sticking to it.

All in all it’s a unique project that not only brings sound to a room but a pleasing physical visualization as well. Being able to listen to music or podcasts on a portable speaker, rather than the tinny internal speakers of a phone or laptop, is the sort of thing you think you can live without until you get used to having higher quality sound easily and in every place you go. And, if there’s a way to improve on that small but crucial foundation with something like a dancing ferrofluid that moves with the music the speaker is playing, then we’re going to embrace that as well.

Adjustable, Piston-Damped Hammer

April 19, 2021 by 27 Comments

When all you have is a hammer, every problem is a constant quest for an even better hammer, as the popular saying goes. At least, that seems to be [Ebenisterie Éloïse]’s situation. She wanted a deadblow hammer that not only had an aesthetically pleasing wood and brass construction, but also one that included adjustable dampers to make sure that each hammer swing is as efficient as possible.

For those unfamiliar with specialty hammers, dead blow hammers typically have some movable mass such as sand or lead shot within the hammer head. This mass shifts forward when the hammer strikes an object, reducing rebound of the hammer off of the object and transferring more energy into each strike. This hammer omits a passive mass in favor of four custom-machined brass tubes, each of which holds a weighted fluid, a spring, and brass weight. Each piston acts as a damper in a similar way to a shock absorber on a vehicle, and a screw and o-ring at the top of each one allows them to be adjustable by adding different weight fluids as needed. Some detailed testing of the pistons shows a marked improvement over any of the passive mass varieties as well.

Not only is this an incredible amount of detail and precision for a tool that is often wielded in a non-precise way (at least among those of us for who aren’t skilled craftspeople), but it is also made out of wood, leather, and brass which gives it an improved look and feel over a plastic and fiberglass hammer that is typical of most modern deadblow hammers. It even rivals this engineer’s hammer with its intricate custom engraving in craftsmanship alone.

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8-Bit Computer Addresses LEDs

April 19, 2021 by 2 Comments

Homebrew 8-bit computers tend to have fairly limited displays, often one or more seven-segment displays and an array of LEDs to show the values of RAM or perhaps some other states of the computer. [Duncan] is in the process of building just such an computer, but wondered if there was a way to create a more visually appealing display while still keeping the computer true to its 8-bit roots. With some interesting TTL logic he was able to create this addressable RGB LED display to some remarkable results.

The array works by controlling the WS2812B LED strips with a specific timing cycle which was pioneered by [Tim] for a different project. [Tim] was able to perform this timing cycle with some simple Assembly code, which means that [Duncan] could convert that code into TTL gate logic relatively easily. Using 74LS02 NOR chips gets the job done as far as timing goes, and the pulses are then fed into a shift register and support logic which then creates the signal for the LED strips.

When everything is said and done, [Duncan] has a fully addressable 16×16 RGB LED array as a display for his 8-bit computer without violating any of his design principles and keeping everything to discrete TTL logic chips and a stick of RAM. It’s a unique method of display that might go along really well with any other homebrew computer like this one that’s also built with 74LS chips.

DOS Gaming PC Gets Necessary Updates

April 17, 2021 by 10 Comments

PC-104 is a standard computer form factor that most people outside of industrial settings probably haven’t seen before. It’s essentially an Intel 486 processor with lots of support for standards that have long since disappeared from most computers, but this makes it great for two things: controlling old industrial equipment and running classic DOS games on native hardware. For the latter, we turn once again to [The Rasteri] who is improving on his previous build with an even smaller DOS gaming rig, this time based on a platform even more diminutive than PC-104.

The key of a build like this is that it needs native support for the long-obsolete ISA bus to be able to interface with a SoundBlaster card, a gold standard for video games of the era. This smaller computer still has this functionality in a smaller package, but with some major improvements. First, it has a floating point unit so it can run games like Quake. It’s also much faster than the PC-104 system and uses less power. Finally, it fits in an even smaller case.

The build goes well beyond simply running software on a SoM computer. [The Rasteri] also custom built an interface board for this project, complete with all of the necessary ports and an ISA sound chip, all while keeping size down to a minimum. The new build also lets him give the build a better name than the old one (although he phrases this upgrade slightly differently), and will also let him expand some features in the future as well. Be sure to check out that first build if you’re new to this saga, too.

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DOOM On A Bootloader Is The Ultimate Cheat Code

April 16, 2021 by 14 Comments

Porting DOOM to run on hardware never meant to run it is a tradition as old as time. Getting it to run on embedded devices, ancient computers, virtual computers, and antique video game consoles are all classic hacks, but what DOOM ports have been waiting for is something with universal applicability that don’t need a bespoke solution for each piece of hardware. Something like DOOM running within a bootloader.

The bootloader that [Ahmad] works with is called Barebox and is focused on embedded systems, often those running Linux. This is the perfect environment for direct hardware access, since the bootloader doubles as a bare metal hardware bring-up toolkit. Now that DOOM runs on this bootloader, it effectively can run anywhere from embedded devices to laptops with minimal work, and although running it in a bootloader takes away a lot of the hard work that would normally need to be done during a port, it may still need some tweaking for specific hardware not otherwise supported.

For those already running Barebox, the bareDOOM code can be found on [Ahmad]’s GitHub page. For those not running Barebox, it does have a number of benefits compared to other bootloaders, even apart from its new ability to play classic FPS games. For those who prefer a more custom DOOM setup, though, we are always fans of DOOM running within an NES cartridge.

Photo: AntonioMDA, CC BY-SA 4.0 via Wikimedia Commons

Remote Controlled Car Gets Active Suspension

April 14, 2021 by 14 Comments

Active suspensions are almost a holy grail for cars, adding so much performance gain that certain types have even been banned from Formula 1 racing. That doesn’t stop them from being used on a wide variety of luxury and performance cars, though, as they can easily be tuned on the fly for comfort or improved handling. They also can be fitted to remote controlled cars as [Indeterminate Design] shows with this electronic servo-operated active suspension system for his RC truck.

Each of the four servos used in this build is linked to the mounting point of the existing coilover suspension on the truck. This allows the servo to change the angle that the suspension is positioned while the truck is moving. As a result, the truck has a dramatic performance enhancement including a tighter turning radius, more stability, and the capability of doing donuts. The control system runs on an Arduino with an ESP32 to enable live streaming of data, and also includes an MPU6050 to monitor the position of the truck’s frame while it is in motion.

There’s a lot going on in this build especially with regard to the control system that handles all of the servos. Right now it’s only programmed to try to keep the truck’s body relatively level, but [Indeterminate Design] plans to program several additional control modes in the future. There’s a lot of considerations to make with a system like this, and even more if you want to accommodate for Rocket League-like jumps. Continue reading “Remote Controlled Car Gets Active Suspension” →

A Lot Of Effort For A Pi Laptop

April 13, 2021 by 7 Comments

Building a Raspberry Pi laptop is not that uncommon. In fact, just a few clicks from any of the major electronics suppliers will have the parts needed for such a project speeding on their way to your house in no time at all. But [joekutz] holds the uncontroversial belief that the value in these parts has somewhat diminishing returns, so he struck out to build his own Pi laptop with a €4 DVD player screen and a whole lot of circuit wizardry to make his parts bin laptop work.

The major hurdle that he needed to overcome was how to power both the display and the Pi with the two small battery banks he had on hand. Getting 5V for the Pi was easy enough, but the display requires 8V so he added one lithium ion battery in series (with its own fuse) in order to reach the required voltage. This does make charging slightly difficult but he also has a unique four-pole break-before-make switch on hand which doesn’t exactly simplify things, but it does make the project function without the risk of short-circuiting any of the batteries he used.

The project also makes use of an interesting custom circuit which provides low voltage protection for that one lonely lithium battery as well. All in all it’s a master course in using some quality circuit-building skills and electrical theory to make do with on-hand parts (and some 3D printing) rather than simply buying one’s way out of a problem. And the end result is something that’s great for anything from watching movies to playing some retro games.

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