Mechanical Skeeball built from Knex

We don’t really know what to say. This Skeeball cabinet is built entirely from Knex. It works exactly how you’d expect Skeeball to work. You plug in quarter and it dispenses balls and keeps score.

[Shadowman39] worked on the build for more than a year. Everything that went into it is a Knex part with the exception of a few rubber bands, and the paper numbers that are used on the scoreboard. There are six motors which drive the machine. Four of them are responsible for turning the scoreboard digits, the others handle ball return.

The link at the top starts off with a bunch of images of the various parts, but you’ll want to watch the video after the break for a closer look. It shows the coin hopper in greater detail. It’s built to only accept quarters and to reject all other coins.

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Antique Electromechanical Calculating Machines

electromechanical calculator Hamann 505

The decision to use electronics for our calculating machines has long been decided.  However, that doesn’t mean that mechanical engineers didn’t put up a valiant, if ultimately futile, fight. [] has an interesting article comparing the calculating technology of the 1960s, such as the [Haman 505], to today’s iPad.

This comparison and pictures were made possible by [Mark Glusker]’s excellent collection.  These models can be divided into two categories, rotary calculators, and printing calculators. According to [Mark]‘s site, the printing calculators stayed on the market a few years after the rotary calculators, which were off the market by 1970.

Although we may never see machines like these made again, anyone even a little bit mechanically inclined would be hard pressed not to be inspired by this collection. Be sure to check out the video of a [Madas 20BTG] calculator after the break to see what one of the rotary models looks like in action! Continue reading “Antique Electromechanical Calculating Machines”

Engine Hacks – Tesla turbines

Engine Hacks Theme banner

You probably weren’t expecting a project based on [Nikola Tesla’s] work to show up during the Engine Hacks theme. Most people know of him because of his pioneering work with high voltage equipment. Never the less, [Tesla] designed a device that later became known as the Tesla Turbine. Tesla turbines are made out of a series of thin disks attached to a central rotor. Air or steam is injected into the closed turbine housing at the outer edge of the disks. It swirls around through the turbine blades and eventually exits near the rotor. This type of turbine can achieve very high rotational speeds but doesn’t have a lot of torque, which limits their usefulness. Check out this instructable that shows you how to build your own Tesla turbine out of hard drive platters.

We have featured a Tesla turbine in the past on Hackaday. In this previous post, [Rick] shows us how to carve a pumpkin with a skill saw blade that is powered by one of these turbines.

Robotic arm and claw sculpted entirely from ShapeLock


[Alexey] wrote in to share a mechanical claw (Google Translation) he has been hard at work on for quite some time. While a lot of people will turn to some sort of 3D plastic printer such as the MakerBot if they need plastic parts built, [Alexey] didn’t have access to one. Instead, he carefully crafted the entire mechanism from polycaprolactone, or as it’s more commonly known, Shapelock.

Using a wide range of tools from hair dryers and knives to lighting fixtures, he manually sculpted the claw and its control arm out of plastic, piece by piece. We are particularly impressed by the gearing he was able to cut from the plastic, which can be finicky at times.

As you can see in the video below, The claw mimics each movement he makes with the control arm via a handful of Arduino-driven servos. Everything seems to work quite well, and despite the rough translation by Google, we think this is a great project. If you are looking to do something similar yourself, he has plenty of pictures on his site, which should give you a pretty good idea as to how things were put together.

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The Lego Synchro Drive

[M-byte] wrote in to tell us about the Lego Synchro Drive. Although not a new hack, this autonomous vehicle is quite amazing in it’s simplicity.  Using only one motor turning at a constant speed, this device is able to navigate obstacles by simply turning.

As [m-byte] was quick to point out, this is a simple task using modern electronics, but this drive is made using only Lego Technic parts. The machine’s motion is quite pleasing. When it hits an obstacle, the outer rotating ring stops, allowing the casters on the bottom to switch direction. One could see this invention coming out of Leonardo da Vinci’s notebook (minus the Legos).

Check out either of the embedded videos after the break to see this device in action. If you’d like to build one yourself, follow this link for very well illustrated directions. Continue reading “The Lego Synchro Drive”

Mechanical Twitter feed for offline reading


Twitter can be a great tool for keeping up to date with your favorite person/company/band/etc. You can find a Twitter client for just about anything that plugs in these days, but sometimes we find that we simply need a break from our computers and smart phones – even if just for a few minutes. What happens when you want to unplug, but still need to know what everyone is up to?

[Patrick Dinnen] asked himself the same thing, and decided that the solution was a mechanical Twitter feed display. The display consists of a static user list strung up against the wall, with a mobile speech bubble mounted next to it. The bubble moves to the user who has most recently updated their status (presumably using a pair of servos), and uses a projector to display their messages. The effect is pretty neat, and it still allows you to get your Twitter fix without staring blankly at your computer screen or smart phone.

We think it would be even cooler if it used a projector on both sides, enabling it to dynamically shuffle through users and status messages at the same time. [Patrick] says that for right now it is merely a proof of concept, so there is no telling how he’ll tweak it going forward.

Continue reading to see his mechanical Twitter feed in action.

[via Adafruit]

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Mechanical Turing machine can compute anything…slowly


For several years, [Jim] has wanted to construct a fully-mechanical universal Turing machine. Without the help of any electronic circuits or electrical input, his goal was to build the machine using simple hand tools and scrap materials.

If you are not familiar with the concept of a Turing machine, they are devices that manipulate symbols or input from a strip of tape, according to a set table of rules. By definition, a Turing machine should be adaptable to simulate the logic of any computer algorithm, albeit in a much slower fashion than you would see from a computer.

He has replaced the strip of tape with a wire grid, and the symbols have been implemented in the form of ball bearings placed on the aforementioned grid. His hand-cranked machine uses magnets to lift the input symbols from the grid, processing them according to the rules table he routed out of a wood block.

The implementation is definitely clever, though [Jim] admits it is not without its problems. He took it to Maker Faire UK, and most people didn’t quite understand what they were seeing without a full explanation.  The machine is not quite as reliable as he would like it to be, and he would like to make it a bit more powerful as it currently would take months to add two numbers together.

Keep reading to see a brief video demo of his Turing machine in action, and check out his blog if you want to see more information on how the machine was built.

Interested in seeing more Turing machines? Check out these two machines we featured a while back.

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