Long before electricity was a common household utility, humanity had been building machines to do many tasks that we’d now just strap a motor or set of batteries onto and think nothing of it. Transportation, manufacturing, agriculture, and essentially everything had non-electric analogs, and perhaps surprisingly, there were mechanical computers as well. Electronics-based computers are far superior in essentially every way, but the aesthetics of a mechanical computer are still unmatched, like this 8-bit machine built from K’nex.

More after the break…

The K’nex computer is built by [Shadowman39], and this first video features just the ALU. It can accept numbers from 0-255 or -128 to 127 and can add two of these numbers by storing them in registers using levers to represent each digit. A drive system underneath with a rack and pinion system operates on each digit, eventually outputting the sum. It can also perform other mathematical operations like subtraction and handling negative numbers using the two’s complement method.

Although this video only goes over the ALU for the mechanical computer, we look forward to [Shadowman39]’s future videos, which go over the other parts of the machine. The basics of the computer are shown in intricate detail. Mechanical computers like these, while generally built as passion projects and not as usable computers, are excellent ways to get a deeper understanding of their electronics-based cousins. Another way to dive deep into this sort of computing world is by building a relay computer.

Quality 3D printing is a common hobbyist tool nowadays, and [wontonnn]’s mini arcade car racing game really shows off how 3D printing can bring parts from functional to fantastic. There are quite a few details we like in [wontonn]’s design, so let’s take a closer look.

The mini mechanical game is one of those treadmill-based car racing games in which the player navigates a little car between an onslaught of belt-borne obstacles. A little DC motor spins things up in a modular side assembly, and a hand-cranked option is available. The player’s car attaches via a magnet to a steering arm; if the player’s car gets knocked off the magnet, game over.

Treadmill belt segments print as large pre-assembled pieces, with ends that snap together without connectors. Belts like this are sometimes tricky, so this is worth keeping in mind should one ever need a similar part. Since there are no external fasteners or hardware to depend on, one could resize it easily to suit their own project purposes.

The finishing touches on the whole assembly look great. It used to be that the sort of colors and lettering seen here would come from a sticker or label, but [wontonn] gets clean lines and colors by raising (or sinking) different parts of the design. The checkerboard pattern, for example, has the light squares raised for printing in a different color.

Electromechanical arcade games have an appeal all their own, being a fusion of both mechanical and electric design that comes together in a special way. Want to make your own? Get inspired by the classic Lunar Lander reimagined, or check out this LEGO treadmill racer that takes an entirely different approach to the concept.

Lego’s Technic line features all kinds of mechanical devices, from cogs to gears to chains and even pneumatic components. However, the vast majority of these components are made out of plastic and are only capable of toy-like levels of performance. In the competitive world of Lego YouTube, builders often push these parts to their limits, breaking them more often than you might think. To that end, [Brick Experiment Channel] has been investigating stouter Lego-compatible universal joints from a variety of third-party manufacturers.

The video starts with a simple demonstration, showing that a Lego universal joint pops apart at just 0.4 Nm of torque. It’s no surprise, given it relies on tiny plastic pins in snap-fit joints. However, this means that it’s not that hard to build a stronger universal joint to outperform the stock parts.

The video steps through a range of other options available on the market. For example, CaDA builds a universal joint using aluminium sleeves, a copper center, and steel pins to join everything together. It’s so strong that the plastic Lego axles fail long before the joint does. Tested with third-party aluminum axles, it eventually fails at 2.3 Nm of torque when the aluminum sleeve snaps. An all-steel joint from MTP goes even harder, eventually stripping out its axle mount at 4 Nm. The rest of the video goes on to explore angular performance, size, and other design features.

It’s fair to say that if you’re swapping out universal joints and axles for aluminum steel parts, you’re not really playing with Lego anymore. At the same time, it’s neat that there exists a sort of defacto standard kit for mechanical experimentation that is now being expanded upon with stronger components. Video after the break.

If William Gibson and Bruce Sterling had written an arcade scene into “The Difference Engine”, it probably would have looked a lot like [Pete Wood]’s Meccano Martian Mission, as illustrated in the video below by the [London Meccano Club]. Meccano Martian Mission is an homage to Atari’s 1978 Lunar Lander video game, but entirely electromechanical and made of– you guessed it– Meccano.

You might think Meccano is “too modern” to count as steampunk, but it squeaks just into the Victorian era. The first sets hit stores in 1901, the last year of Queen Victoria’s long reign. Since then, Meccano has developed a large following that has produced some truly impressive constructions, and this arcade game can stand amongst the best of them.

The game has all the features of the original: a swiveling spaceship, two-axis speed control, and even a little yellow flame that pops out when you are applying thrust. There’s a timer and a fuel gauge, and just like the original, there are easier and harder landing pads that offer score multipliers. While the score must be totted up manually, the game will detect a crash and flag it with a pop-down banner. It really has to be seen to be believed. It’s all done with cams and differentials hitting potentiometers and microswitches — not an Arduino in sight; [Pete] does a good job explaining it in the second half of the embedded video, starting about 10 minutes in.

Sure, might not be new or groundbreaking — these are old, old techniques — but not many people know them well enough to use them anymore, especially not with this degree of sophistication. To see these electromechanical techniques applied anachronistically to replicate one of the great pioneers of the arcade world tickles our fancy. It’s no wonder that perfecting this mechanical marvel has taken [Pete Wood] a decade.

The project reminds us of the Meccano Pinball Machine featured here years ago, but that somehow felt like a more natural fit for the apparently undead building kits. We lamented Meccano’s demise in 2023,but the brand is apparently being revived this year. Hopefully, that means there can be more young members for the [London Meccano Club] and groups like them, to keep the perforated-steel flame alive through another six reigns.

This hack is the bee’s knees, and we’re very thankful to [Tim Surtell] for the tip. Remember, the tip line is always open!.