The Difference Between 4WD And AWD

March 31, 2021 by Zoe Skyforest 102 Comments

Car manufacturers will often tout a vehicle’s features to appeal to the market, and this often leads to advertisements featuring a cacophony of acronyms and buzzwords to dazzle and confuse the prospective buyer. This can be particularly obvious when looking at drivelines. The terms four-wheel drive, all-wheel drive, and full-time and part-time are bandied about, but what do they actually mean? Are they all the same, meaning all wheels are driven or is there more to it? Let’s dive into the technology and find out.

Part-Time 4WD

Part-time four-wheel drive is the simplest system, most commonly found on older off-road vehicles like Jeeps, Land Cruisers and Land Rovers up to the early 1990s, as well as pickup trucks and other heavy duty applications. In these vehicles, the engine sends its power to a transfer case, which sends an equal amount of torque to the front and rear differentials, and essentially ties their input shafts together. This is good for slippery off-road situations, as some torque is provided to both axles at all times. However, this system has the drawback that it can’t be driven in four-wheel drive mode at all times. With the front and rear differentials rotating together, any difference in rotational speed between the front and rear wheels — such as from turning a corner or uneven tyre wear — would cause a problem. The drive shaft going to one differential would want to turn further than the other, a problem known as wind-up.

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Sawblade Turned Beyblade Looks Painful To Tangle With

March 30, 2021 by Zoe Skyforest 14 Comments

Beyblades were a huge craze quite some years back. Children battled with spinning tops in small plastic arenas, or, if their local toy stores were poorly merchandised, in salad bowls and old pie dishes. The toys were safe enough, despite their destructive ethos, by virtue of being relatively small and lightweight. This “Beyblade” from [i did a thing] is anything but, however.

The build begins with a circular saw blade over 1 foot in diameter, replete with many angry cutting teeth that alone portend danger for any individual unlucky enough to cross its path. Saw blades tend to cut slowly and surely however, so to allow the illicit Bey to deal more traumatic blows, a pair of steel scraps are welded on to deliver striking blows as well. This has the added benefit of adding more mass to the outside of the ‘blade, increasing the energy stored as it spins.

With the terrifying contraption spun up to great RPM by a chainsaw reeling in string, it’s able to demolish cheap wood and bone with little resistance. Shrapnel is thrown in many directions as the spinner attacks various objects, from a melon to an old CRT TV. We’d love to see the concept taken further, with an even deadlier design spun up to even higher speeds, ideally with a different tip that creates a more aggressive motion across the floor.

As aggressive as this saw blade looks in action, not all are so scary. Even paper can do the job under the right conditions. Video after the break.

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Pneumatic Actuator Made Out Of Lasercut Plastic

March 30, 2021 by Zoe Skyforest 17 Comments

Pneumatics are a great solution for all kinds of actuators, and can even be used for logic operations if you’re so inclined. Typically, such actuators rely on nicely machined metal components with airtight rubber seals. But what if you did away with all that? [Richard Sewell] decided to investigate.

The result is a pneumatic actuator built out of lasercut acetal parts. The mechanism consists of of two outer layers of plastic acting as the enclosure, and a cut-out middle layer which creates the air chamber and houses the actuating arm itself. It’s a single-acting design, meaning the air can push the actuator one way, with a spring for return to the neutral position. The action is quite fast and snappy, too.

[Richard] aims to tweak the design further by improving the registration between the features of each layer and reduce the rubbing of the actuator’s rotor on the surrounding parts. If you’ve got the know-how, sound off in the comments. Alternatively, consider looking into soft pneumatics as well. Video after the break.

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A Floppy Controller For The Raspberry Pi

March 30, 2021 by Zoe Skyforest 27 Comments

The Raspberry Pi is the darling single board computer that is everything to everyone. It even has lit up the eyes of the older set with the Pi 400 mimicking the all-in-one keyboard computer design so popular in the 1980s. Another project that harkens back to that golden era is this Raspberry Pi floppy controller board from [Dr. Scott M. Baker].

[Scott] is no stranger to floppy controllers, having worked with the popular WD37C65 floppy controller IC before with the RC2014 homebrew Z80 computer. Thus, it was his part of choice when looking to implement a floppy interface on the Raspberry Pi. The job was straightforward, and done with just the IC itself. Despite the Pi running at 3.3 V and the controller at 5 V, [Scott] has found no problems thus far, implementing just a resistor pack to try and limit damage from the controller sending higher voltage signals back to the Pi. With that said, he plans to implement a proper level shifter down the road to ensure trouble-free operation long term.

The project is rounded out with a bunch of Python tools used to interface with the controller, available on Github. Performance is limited by the non-realtime nature of the Raspberry Pi’s user mode operation, which [Scott] notes could be fixed with a kernel module. With that said, if you’re looking for performance, floppies aren’t it anyway.

We do love the Pi put to use in retro tasks; it can even be a SCSI Swiss Army Knife if you need one. Video after the break.

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High-End Case Mods To A PlayStation 5

March 30, 2021 by Zoe Skyforest 10 Comments

Modern consoles bring joy to televisions around the globe, but they’re fundamentally mass-produced totems to gaming excellence. That wasn’t good enough for [Matt], who decided that his PlayStation 5 needed a total case makeover. (Video, embedded below.)

The material of choice is brass. Capable of being polished to a mirror-like shine while being readily workable and available, it’s perfect for making a PlayStation 5 look just a little more deluxe. While [Matt] has worked with brass before, replicating the PS5’s case in the metal pushed him to learn new skills. The main center divider was easy enough, with paper used to create a cutting template to match the form which bends through 90 degrees. The real challenge, however, was the side panels. With complex curves across several axes, manually bending metal plates to match the shape proved impossible. Instead, a custom wooden and plaster jig was made, onto which brass plates could be clamped to match the curves. A blowtorch was then used to release the plate’s internal stresses in a process called normalisation.

[Matt] does a great job of making the whole thing look easy. With that said, the final results are stunning enough that we’re sure it would be difficult to replicate without a lot of experience and attention to detail. In particular, the deft way the side panel clips were dealt with had us nodding in sage approval. The final console makes a great companion for the brass-housed monitor [Matt] created for his [DIY Perks] channel quite recently. Video after the break.

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The Sixtyforgan Proves That Church Organs Are Definitely Chiptune

March 29, 2021 by Zoe Skyforest 44 Comments

Church organs may be mechanically complicated and super old-school, but they share something in common with the earliest computer sound chips. In theory, and largely in practice, they produce very simple waveforms. The primary reason that church organs seem so full and rich compared to your old Commodore 64 is that they have the benefit of a whole church’s worth of reverb to fatten out the sound. [Linus] demonstrates this with the Sixtyforgan.

The Sixtyforgan is a Commodore 64 hooked up to a spring reverb tank. By running the relatively basic waveforms from the Commodore’s SID chip through this reverb, it’s possible to generate sounds that are eerily similar to those you might hear at your local Sunday service. While we won’t expect chiptune luminaries like [chipzel] to start busting out songs of praise at events like Square Sounds, it’s kind of awesome to think of the composers of antiquity rocking out to some mad Game Boy jams way back when.

It’s a great demonstration of the Commodore’s musical abilities, and we particularly like the application of the chromatic button layout borrowed from the accordion. We’d love to see this setup combined with an orchestra of the retro computers, like this demonstration playing The Sugar Plum Fairy. Alternatively, Billy Corgan on the Sixtyforgan playing Tiberius would be pretty great, too. Pretty sounding video after the break.

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Skid Steer Robot Chassis Takes A Beating

March 26, 2021 by Zoe Skyforest 5 Comments

[Engineering After Hours] wanted a highly maneuverable robot chassis with a tight turning radius. Skid steering seemed to be the perfect solution, but the available commercial options didn’t take his fancy. Thus, a custom build was the answer – with impressive results.

The build packs two large RC motors, one for each side, with each driving two wheels through a belt drive. This reduces the electronics required to the bare minimum for skid steering. It’s all assembled within a plasma-cut metal chassis which is more than tough enough to take some hard knocks.

One of the primary goals on the build was to eliminate the risk of vibrations and shock damaging the motors and gearboxes. Many off-the-shelf designs couple the wheels directly to gearbox output shafts, potentially damaging the expensive components over time. In this design, a separate bearing assembly is used to take the load from the wheels instead.

It’s a great example of how an engineering-first approach can build a sturdy ‘bot with a minimum of fuss. Outfitted with some fat off-road tyres the performance is impressive, with the ‘bot having no trouble tearing it up in mud, snow, and water.

We’ve seen other great builds from [Engineering After Hours] before, like the active aero RC build. Video after the break.

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