Wooden Tank’s Movement Hinges On Hinges

September 9, 2020 by Brian McEvoy 28 Comments

When we first looked at this tank, we thought it was pretty cool. The sides are unpainted 1/2″ (12mm) plywood, so it is not flashy. The dimensions came from Google-fu-ing the heck out of the WWII Hetzer and scaling them to 1:6. What knocks our socks off is how much [Bret Tallent] made use of parts you would find in a hardware store or bicycle shop. He uses twin motors from electric bikes, and the wheels look like replacement shopping cart wheels. The best part is the treads, which are dozens of hinges fastened with pairs of bolts and nylon-insert nuts. Something is reassuring about knowing that a repair to your baby is no further than a bike ride.

We don’t know what started [Bret] on his path to sidewalk superiority, but we suspect he is cooped up like the rest of us and looking to express himself. Mini-Hetzer is not licensed by Power Wheels and never will be, so it probably won’t turn into a business anytime soon. There is a complete gallery starting with an empty plywood base, and the pictures tell the story of how this yard Jäger got to this point. There are plans to add a paintball gun and streaming video, so we’d advise that you don’t mess with the jack-o-lanterns on his block this year. Give his gallery a view and see if you don’t become inspired to cobble something clever from the hardware store too. Then, tell us about it.

Another creative hacker used wood for their tank body and the treads as well. If you like your treaded vehicles functional, we have one meant to taxi small planes over the tarmac.

AUTOVON: A Phone System Fit For The Military

September 9, 2020 by Dan Maloney 62 Comments

It’s a common enough Hollywood trope that we’ve all probably seen it: the general, chest bespangled with medals and ribbons, gazes at a big screen swarming with the phosphor traces of incoming ICBMs, defeatedly picks up the phone and somberly intones, “Get me the president.” We’re left on the edge of our seats as we ponder what it must be like to have to deliver the bad news to the boss, knowing full well that his response will literally light the world on fire.

Scenes like that work because we suspect that real-life versions of it probably played out dozens of times during the Cold War, and likely once or twice since its official conclusion. Such scenes also play into our suspicion that military and political leaders have at their disposal technologies that are vastly superior to what’s available to consumers, chief among them being special communications networks that provide capabilities we could only have dreamed of back then.

As it turns out, the US military did indeed have different and better telephone capabilities during the Cold War than those enjoyed by their civilian counterparts. But as we shall see, the increased capabilities of the network that came to be known as AUTOVON didn’t come so much from better technology, but more from duplicating the existing public switched-telephone network and using good engineering principles, a lot of concrete, and a dash of paranoia to protect it.

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Building An Affordable Press For Heat Set Inserts

September 9, 2020 by Tom Nardi 11 Comments

If you’re building mechanical assemblies with 3D printed parts, you’ll quickly realize that driving machine screws into thermoplastic isn’t exactly an ideal solution. It can work in a pinch, but you can easily strip the threads if you crank down too hard. The plastic holes can also get worn down from repeated use, which is a problem if you’re working on something that needs to be taken apart and reassembled frequently. In those situations, using brass heat set inserts gives the fasteners something stronger to bite into.

You can install these inserts by hand, but if you plan on doing a lot of them, a dedicated press station like the one [Chris Chimienti] recently put together will save you a lot of aggravation in the long run. In the video after the break he walks viewers through the design and use of the device, which itself relies on a number of 3D printed parts using the very same inserts it’s designed to install.

The spring-loaded arm can slide up and down the extrusion to adjust for height.

To build this tool you’ll need a piece of aluminum extrusion, some smooth rod, a couple springs, and an assortment of fasteners. Nothing that wouldn’t likely be in the parts bin of anyone who’s been tinkering with 3D printers for awhile, though even if you had to buy everything, the Bill of Materials will hardly break the bank. For the base you can use a piece of scrap wood, though [Chris] has opted to make it a storage compartment where he can store the inserts themselves. We really like this approach, but obviously you’ll need to have access to woodworking tools in that case.

Clearly shopping on the top shelf, [Chris] purchased a kit that actually came with a Weller soldering iron and the appropriate tips for the various sized inserts. If you’re like us and just buy the inserts that come in a plastic baggie, you may need to adapt the arm to fit your iron of choice. That said, the idea of having a dedicated iron that you can leave mounted in the press makes a lot of sense to us if you can swing it.

[Joshua Vasquez] wrote up a phenomenal guide to getting started with heat set inserts last year that’s an absolute must-read for anyone interested in the concept. Whether you build a dedicated press or just push them in freehand, his tips and tricks will help insure you get the best result possible.

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Google Turns Android Up To 11 With Latest Update

September 9, 2020 by Tom Nardi 32 Comments

Just going by the numbers, it’s a pretty safe bet that most Hackaday readers own an Android device. Even if Google’s mobile operating system isn’t running on your primary smartphone, there’s a good chance it’s on your tablet, e-reader, smart TV, car radio, or maybe even your fridge. Android is everywhere, and while the development of this Linux-based OS has been rocky at times, the general consensus is that it seems to have been moving in the right direction over the last few years. Assuming your devices actually get the latest and greatest update, anyway.

So it’s not much of a surprise that Android 11, which was officially released yesterday, isn’t a huge update. There’s no fundamental changes in the core OS, because frankly, there’s really not a whole lot that really needs changing. Android has become mature enough that from here on out we’re likely to just see bug fixes and little quality of life improvements. Eventually Google will upset the apple cart (no pun intended) with a completely new mobile OS, but we’re not there yet.

Of course, that’s not to say there aren’t some interesting changes in Android 11. Or more specifically, changes that may actually be of interest to the average Hackaday reader. Let’s take a look at a handful of changes and tweaks worth noting for the more technical crowd.

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Tesla Coil Electric Bike Is Wireless

September 9, 2020 by Bryan Cockfield 28 Comments

Electric bikes, and really all electric vehicles, have one major downside: the weight and cost of batteries. Even with lithium, battery packs for ebikes can easily weigh more than the bike itself and cost almost as much. But having to deal with this shortcoming could be a thing of the past thanks to [LightningOnDemand]’s recent creation. Of course, this would rely on a vast infrastructure of Tesla coils since that’s how this bike receives the power it needs to run its electric motor.

The Tesla coil used for the demonstration is no slouch, either. It’s part of the Nevada Lightning Laboratory and can pack a serious punch (PDF warning). To receive the electrical energy from the coil, the bike (actually a tricycle) uses a metal “umbrella” of sorts which then sends the energy to the electric motor. The bike drags a chain behind itself in order to have a ground point for the electricity to complete its circuit. There is limited range, though, and the Tesla coil will start ionizing paths to the ground if the bike travels too far away.

While we can’t realistically expect Tesla’s idea of worldwide, free, wireless electricity to power our bicycles anytime soon, it is interesting to see his work proven out, even if its on a small scale like this. Of course, it doesn’t take a research laboratory to start working with Tesla coils. This one is built out of common household parts and still gets the voltages required to create the signature effects of a Tesla coil.

Thanks to [Adam] for the tip!

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Paper Keyboard Is Self-Powered

September 9, 2020 by Al Williams 12 Comments

Building a keyboard isn’t a big project these days. Controller chips and boards are readily available, switches are easy to find, and a 3D printer can do a lot of what used to be the hard parts. But engineers at Purdue have printed a self-powered Bluetooth keyboard on an ordinary sheet of paper. You can see videos of the keyboards at work below.

The keyboards work by coating paper with a highly fluorinated coating that repels water, oil, and dust. Special inks print triboelectric circuits so that pressing your finger on a particular part of the paper generates electricity. We were skeptical that the Bluetooth part is self-powered, although maybe it is possible if you have some very low-power electronics or you manage the power generated very carefully.

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LEGO Delivers Corvette Experience On A Budget

September 8, 2020 by Tom Nardi 5 Comments

Many dream of tooling around in a high performance sports car, but the cost of owning, maintaining, and insuring one of them make it a difficult proposition. While this LEGO version of the Corvette ZR1 might not be exactly like the real thing, it’s 4-speed manual and electronic gauge cluster can give you a taste of the supercar lifestyle without having to taken out a second mortgage.

Built by [HyperBlue], this desktop speedster has more going on under the hood (or more accurately, the roof) than you might expect. While it looks pretty unassuming from the outside, once the top is lifted, you can see all the additional components that have been packed in to motorize it. The functional gearbox takes up almost the entire interior of the car, but it’s not like you were going to be able to fit in there anyway.

But the motorized car is really only half of the project. [HyperBlue] has built a chassis dynamometer for his plastic ride that not only allows you to “start” the engine with realistic sights and sounds (recorded from an actual GM LT1 V8 engine), but put the mini ‘Vette through its paces. With a virtual dashboard powered by the Raspberry Pi, you can see various stats about the vehicle such as throttle position, RPM, and calculated scale speed; providing a real-world demonstration of how the transmission operates.

While a LEGO sports car might not be quite as exciting as getting yourself a real project car, there’s something to be said for being able to rebuild your transmission without getting your hands dirty.

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