Build Your Own Hydroelectric Dam

We have to admit that we often think about building unusual things, but we hadn’t really considered building our own hydroelectric dam before. [Mini Construction] did, apparently, and there’s a timelapse of the build in the video below.

We wished this was more of a how-to video, although if you are handy with brickwork, the mechanical construction seems straightforward. Presumably, you’d need to understand how much force the water had but we don’t know if there was math involved or just seat-of-the-pants design.

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Newly Completed Overly-Complex Clock Synchronizes Multiple Mechanisms

Some time ago [Kelton] was working on a clock inspired by Rube Goldberg contraptions. It uses only a single motor, and he’s proud to now show off the finished product (video, embedded below.)

The clock shows hours on the left, and minutes on the right. Every sixty minutes the clock drops a marble. That marble kicks off a series of visually-satisfying operations that culminate in advancing the hour. Then everything resets, and it continues for as long as it has power.

The hour oscillates in a very satisfying manner as it locks in.

At the top of each hour, the minute hand tips a marble with a gravity cam. That marble runs down a track gaining enough momentum to flip a kicker, and a short series of falling dominoes builds enough force to tip and trigger the spring-loaded ratchet that locks in a new hour. You can skip directly to 2:09 if you just want to listen to [Kelton] explain the whole operation from beginning to end.

We think it’s very interesting to note that this clock’s complexity is, if anything, understated. Each of the mechanisms involved must individually reset by their own separate mechanisms, each of which are as intriguing as their showier counterparts, and we’re sure they were every bit as difficult to get just right. And of course, it’s all driven by a single motor.

You may recall the promising start this clock project was off to and we’re delighted to see it come to completion, especially considering its complexity. Not every project sees completion, and fewer still get a version two, but that’s okay. What really floats our boat is seeing the process and details as well as hearing about what worked and what didn’t. We’re glad this clock reached the finish line, but even if something doesn’t work out, there’s always something to learn.

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You Can Build A Little Car That Goes Farther Than You Push It

Can you build a car that travels farther than you push it? [Tom Stanton] shows us that you can, using a capacitor and some nifty design tricks.

[Tom]’s video shows us the construction of a small 3D printed trike with a curious drivetrain. There’s a simple generator on board, which charges a capacitor when the trike is pushed along the ground. When the trike is let go, however, this generator instead acts as a motor, using energy stored in the capacitor to drive the trike further.

When put to the test by [Tom], both a freewheeling car and the capacitor car are pushed up to a set speed. But the capacitor car goes farther. The trick is simple – the capacitor car can go further because it has more energy. But how?

It’s all because more work is being done to push the capacitor car up to speed. It stores energy in the capacitor while it’s being accelerated by the human pushing it. In contrast, after being pushed, the freewheeling car merely coasts to a stop as it loses kinetic energy. However, the capacitor car has similar kinetic energy plus the energy stored in its capacitor, which it can use to run its motor.

It’s a neat exploration of some basic physics, and useful learning if you’ve ever wondered about the prospects of perpetual motion machines.

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Celebrating The [Jack Ells] Automatic Photometric Telescope

Here at Hackaday, we take pride in presenting the freshest hacks and the best of what’s going on today in the world of hardware hacking. But sometimes, we stumble upon a hack from the past so compelling that we’ve got to bring it to you, so we can all marvel at what was possible in the Before Times.

This one, a completely homebrewed automatic photometric telescope, was designed and built by the father-son team of [Jack Ells] and [Peter Ells]. From the elder [Ells]’ field notes, the telescope saw its first light in 1988, giving us some idea of the scale of problems that had to be overcome to get this wonderful machine working. The optics are straightforward, as least as telescopes go — it’s an f-4.0 Newtonian reflector with an 8.5″ (221 mm) primary mirror on an equatorial mount. The telescope is very rugged-looking indeed, and even stands on brick piers for stability. The telescope’s mount is controlled by a BBC Micro running custom BASIC software.

For the photometric parts, the [Ells] boys installed a photo-multiplier tube at the focus of the telescope. More precisely, they used a liquid light guide to connect the eyepiece to a rack full of equipment, which included the PM tube, its high-voltage power supply, and a series of signal conditioners and counter circuits. The idea was to view a single star through a pinhole mask over the objective of the telescope and count the rate of photons received over time. Doing so would reveal periodic changes in the star’s brightness. Today we’d use similar data to search for exoplanet transits; while we don’t think that was a thing back in 1988, it looks like this telescope could easily have handled the job.

Sadly, [Jack Ells] died only two years after finishing the telescope. But he left it with his son, who eventually moved it to a location with better seeing conditions, where it gathered data for another eight years. The quality of the work is amazing, and as father-son projects go, this one is tough to beat.

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Giving The Original Xbox 256 MB Of Memory

The original Xbox forever changed the console world, because it was basically just PC components laced together in a slightly different architecture. It featured a Pentium 733 MHz CPU with just 64MB of RAM. [Prehistoricman] has been hard at work, figuring out how to up that to 256MB instead.

This isn’t [Prehistoricman’s] first rodeo. Previously, he managed to up the Xbox’s RAM to 128 MB. To figure out how to go further, he had to figure out the addressing scheme. A datasheet for the Xbox’s original memory chip was a help in this regard, as was the envytools project and an Xbox source code leak.

A BIOS hack was needed to move the auto-precharge pin to free up more address pins for the higher memory space. Furthermore, the only available memory chips that were suitable used BGA packages, so a small PCB with castellated edges was needed to adapt the chip to the Xbox’s motherboard, which expects a TQFP package.

Ultimately, getting this hack to work involved a lot of bare-metal hacking. It also won’t help the performance of commercial games at all, as they were all designed within the limitations of the original console. Still, it’s impressive to see this now-ancient platform hacked to do more. It’s also hilarious to compare it with a contemporary PC, which could simply accept 256 MB of RAM by using additional memory slots. Video after the break.

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Hacking Airline WiFi The Hard Way

We’ve all been there. You are on a flight, there’s WiFi, but you hate to pay the few bucks just to watch dog videos. What to do? Well, we would never suggest you engage in theft of service, but as an intellectual exercise, [Robert Heaton] had an interesting idea. Could the limited free use of the network be coopted to access the general internet? Turns out, the answer is yes.

Admittedly, it is a terrible connection. Here’s how it works. The airline lets you get to your frequent flier account. When there, you can change information such as your name. A machine on the ground can also see that change and make changes, too. That’s all it takes.

It works like a drop box. You take TCP traffic, encode it as fake information for the account and enter it. You then watch for the response via the same channel and reconstitute the TCP traffic from the remote side. Now the network is at your fingertips.

There’s more to it, but you can read about it in the post. It is slow, unreliable, and you definitely shouldn’t be doing it. But from the point of view of a clever hack, we loved it. In fact, [Robert] didn’t do it either. He proved it would work but did all the development using GitHub gist as the drop box. While we appreciate the hack, we also appreciate the ethical behavior!

Some airlines allow free messaging, which is another way to tunnel traffic. If you can connect to something, you can probably find a way to use it as a tunnel.

A green hat with a grey zipper is partially opened revealing the grey mesh inside. It is held by two hands manipulating the zipper. The picture is inside a red circle overlaid on top of a tinted image of a workshop. A red line points to an image of a woman looking to the right wearing the green baseball cap.

Bring Your Reusable Grocery Bag On Your Head

After decades of taking plastic bags for granted, some places now charge for them to help offset some of the environmental damage they cause. If you have a tendency to forget your reusable bags at home but love to wear hats, [Simone Giertz] has the bag hat for you.

Having conquered everything from making the first Tesla pickup to a tambour puzzle table, a hat that can turn into a grocery bag seems like a relatively easy challenge. It was not. One thing that [Giertz] observes early in the process is that fabric is a much less “honest” material since it can move in ways that many of the other materials she works with cannot, like glass or wood.

As with any good project, there are numerous iterations of the bag hat, mostly due to trying to balance the two distinct functions of bag and hat without overly-compromising either. In the end, the hat features a zipper down the center from ear to ear that opens up into a mesh grocery bag. The adjustable loop of the hat does double duty as the bag handle.

If you’d like to build your own sewing machine for projects like this, maybe you should find out how they work. If you’d rather just get on with the sewing bit, we can help you with that too.

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