Do You Smell What The Magic Chef Is Cookin’?

March 19, 2020 by Kristina Panos 6 Comments

Automata are already pretty cool, but the ones that can fool us are something extraordinary. The legendary [Greg Zumwalt] has recently turned his toy-making attentions toward illusory automata, and we think he’s off to a great start with his admirable appetizer, the Magic Chef.

The Chef aims to please, and as long as he has the power to do so, he’ll keep offering dishes from his six-item menu of hamburger, hot dog, pizza slice, BLT, sunny-side-up egg, and banded gelatinous chunk we can’t quite identify. Amazingly, this one-man restaurant does everything with a single 6VDC gear motor, some magnets, and 58 printed parts including gears, cams, and levers. The way the food carousel moves on a sort of magnetic slip ring system is the icing on the cake.

If you want to whip up a Magic Chef of your own, all the STL files are available for take-out from the Instructables page. Hungry for more details? go wash up and get situated after the break, ’cause we’re serving up a demo video with some close-up views of the inner workings. Oh, and here’s some automata-brewed coffee for dessert.

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Can Lego Break Steel?

March 17, 2020 by Dan Maloney 14 Comments

Betteridge’s Law of Headlines holds that any headline ending in a question mark can be answered with a resounding “No”. But as the video below shows, a Lego machine that twists steel asunder is not only possible, it’s an object lesson in metal fatigue. Touché, [Betteridge].

In pitting plastic against metal, the [Brick Experiment Channel] relied on earlier work with a machine that was able to twist a stock plastic axle from the Technics line of parts like a limp noodle. The steel axle in the current work, an aftermarket part that’s apparently no longer available, would not prove such an easy target.

Even after beefing up the test stand with extra Technics struts placed to be loaded in tension, and with gears doubled up and reinforced with extra pins, the single motor was unable to overcome the strength of the axle. It took a second motor and a complicated gear train to begin to deform the axle, but the steel eventually proved too much for the plastic to withstand. Round Two was a bit of a cheat: the same rig with a fresh axle, but this time the motor rotation was constantly switched. The accumulated metal fatigue started as a small crack which grew until the axle was twisted in two.

The [Brick Experiment Channel] is a fun one to check out, and we’ve featured them before. Along with destructive projects like this one, they’ve also got fun builds like this Lego playing card launcher, a Technic drone, and a Lego submarine.

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Silo Launched Model Rocket Goes Thoomp

March 16, 2020 by Danie Conradie 20 Comments

While rockets launched from silos are generally weapons of war, [Joe Barnard] of [BPS.Space] thought model rocketry could still do with a little more thoomp. So he built a functional tube launched model rocket.

Like [Joe]’s other rockets, it features a servo-actuated thrust vectoring system instead of fins for stabilization. The launcher consists of a 98 mm cardboard tube, with a pneumatic piston inside to eject the rocket out of the tube before it ignites its engine in mid-air. When everything works right, the rocket can be seen hanging motionlessly in the air for a split second before the motor kicks in.

The launcher also features a servo controlled hatch, which opens before the rocket is ejected and then closes as soon as the rocket is clear to protect the tube. The rocket itself is recovered using a parachute, and for giggles he added a tiny Tesla Roadster with its own parachute.

Projects as complex as this rarely work on the first attempt, and Thoomp was no exception. Getting the Signal flight computer to ignite the rocket motors at the correct instant proved challenging, and required some tuning on how the accelerometer inputs were used to recognize a launch event. The flight computer is also a very capable data logger, so every launch attempt, failed or successful, became a learning opportunity. Check out the second video after the break for a fascinating look at how all this data was analyzed.

[Joe]’s willingness to fail quickly and repeatedly as part of the learning process is a true display of the hacker spirit. We’ll definitely be keeping a close eye on his work.

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Vanquish Your Foes With Lego Playing Card Machine Gun

March 7, 2020 by Jenny List 14 Comments

There was something exceptionally satisfying about those playground games of cops and robbers when we were young, but they were missing something in that a pretend gun made with your fingers lacks a certain Je ne sais quoi. Our youthful blood-lust demanded something a bit more real, and though the likes of NERF and other toys could supply it their lost projectiles came at a price not all parents could sustain. We’d have given anything for [Brick Experiment Channel]’s rapid-firing Lego playing card gun! (Video, embedded below.)

The principle is simple enough, one of the larger Lego road wheels is spun up to a respectable speed through a gear train from a pair of motors, it’s positioned over a channel through which playing cards are fed, and it picks each one up and accelerates it to a claimed 20 miles per hour. The card is fired off into the distance, ready to take down your Lego figure or plastic drinking cup enemies with maximum prejudice.

It’s clear some significant thought has gone into the firing platform design, with the cards sliding along smooth rails and the wheel sitting in a gap between the rails so that the natural springiness of the card can engage with it. The cards also emerge with a spin, due to the wheel being offset. The mechanism is completed with a third motor which acts as a feeder pushing individual cards from the deck into the main firing platform. This achieves an astonishing six cards per second, as can be seen in the video below the break.

We can see that this is a huge amount of fun, and we hope should any youngsters get their hands on it that there are not lurid tales of kids with playing card injuries. It’s not the first novelty projectile gun we’ve brought you, there have been numerous rubber band guns but our favourite is the automatic paper plane folder and launcher.

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Mini RC Helicopter Becomes Even Smaller Submarine

March 6, 2020 by Tom Nardi 8 Comments

We often think of submarines as fairly complex pieces of machinery, and for good reason. Keeping the electronics watertight can naturally be quite difficult, and maintaining neutral buoyancy while traveling underwater is a considerable engineering challenge. But it turns out that if you’re willing to skip out on those fairly key elements of submarine design, the whole thing suddenly becomes a lot easier. Big surprise, right?

That’s precisely how [Peter Sripol] approached his latest project, which he’s claiming is the world’s smallest remote control submarine. We’re not qualified to say if that’s true or not, but we were certainly interested in seeing how he built the diminutive submersible. Thanks to the fact that it started life as one of those cheap infrared helicopters, it’s actually a fairly approachable project if you’re looking to make one yourself.

The larger prototype version is also very cool.

After testing that the IR communication would actually work as expected underwater, [Peter] liberated the motors and electronics from the helicopter. The motor’s wires were shortened, and the receiver PCB got a slathering of epoxy to try and keep the worst of the water out, but otherwise they were unmodified.

If you’re wondering how the ballast system works, there isn’t one. The 3D printed body angles the motors slightly downwards, so when the submarine is moving forward it’s also being pulled deeper into the water. There aren’t any control surfaces either, differential thrust between the two motors is used to turn left and right. This doesn’t make for a particularly nimble craft, but in the video after the break it certainly looks like they’re having fun with it.

Looking for a slightly more complex 3D printed submersible vehicle? Don’t worry, we’ve got you covered.

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Blister Pack With Jet Fighter Toy Is A Business Card

March 5, 2020 by Jenny List 20 Comments

In the world of business cards, it seems that for some people a white rectangle of card just doesn’t cut it any more. A card isn’t simply a means to display your contact details, instead it can be a way to show off your work and demonstrate to the world your capabilities. For [agepbiz] those are the skills of a 3D design specialist, so what better way to proceed than by distributing a 3D-printed example of his work? How to render that into a business card? Put it in a retail-style blister pack, of course. Take a look at the video below the break.

It’s an interesting process to follow, because there are certainly readers who will have toyed with the idea of selling their work, and this makes an attractive way to display a small assembly while still keeping it safe from damage. The toy – a small 3D-printed jet fighter with working swing wings that’s a masterpiece in itself – is laid on a backing card and a custom blister is glued over it. The manufacture of the printed backing card with a CNC card cutter is shown, followed by that of the blister with a custom SLA-printed mould being used to vacuum-form a sheet of clear plastic. Surprisingly the whole is assembled with just a glue stick, we’d have expected something with a bit more grab. The result is a professional-looking blister packed product of the type you wouldn’t bat an eyelid over if you saw it in a shop, and one of those things that it’s very useful to have some insight into how one might be made..

It’s possible this card might be a little bulky to slip in your wallet, but it’s hardly the only novelty card we’ve brought you over the years. Some of our most recent favourites run Linux or play Tetris.

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Stop ‘n Go DUPLO

March 3, 2020 by Kristina Panos 8 Comments

[beshur]’s 2-year-old is obsessed with transportation, so he lifted a few DUPLO blocks from the bin and made this toy traffic light as a birthday present. Hey, might as well get him used to the realities of traffic, right? It also makes for a good early hacker lesson: why buy something when you can make it yourself?

The traffic pattern is determined by an Arduino Nano V3 situated inside the carved-out rear block. There’s a push button on the side in case there’s a spill and the lights need to go blinking red until the issue is dealt with. Instead of trying to solder everything in situ and risk melting the plastic, [beshur] dead-bugged the LEDs and resistors to the Nano with a helping hands and then worked everything into the case. The 5mm LEDs fit perfectly into the drilled-out posts of a second block and produce a nice, soft glow. Proceed with caution and check it out after the break.

Of course, plastic building blocks can do real work, too. This LEGO chocolate pantograph is pretty sweet.

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