Raspberry Shake Detects Quakes

The Raspberry Pi’s goal, at least while it was being designed and built, was to promote computer science education by making it easier to access a working computer. What its low price tag also enabled was a revolution in distributed computing projects (among other things). One of those projects is the Raspberry Shake, a seismograph tool which can record nearby earthquakes.

Of course, the project just uses the Pi as a cost-effective computing solution. It runs custom software, but if you want to set up your own seismograph then you’ll also need some additional hardware. There are different versions of the Raspberry Shake, the simplest using a single Geophone which is a coil and magnet. Vibrations are detected by sensing the electric signal generated by the magnet moving within the coil of wire. Other models increase the count to three Geophones, or add in MEMS accelerometers, you can easily whip one of these up on your own bench.

The entire setup will fit nicely on a coffee table as well, making it much smaller (and cheaper) than a comparable professional seismograph. Once all of the Raspberry Shakes around the world were networked together, it gives an accurate, real-time view of seismic activity anywhere you can imagine. If you’ve ever been interested in geology or just want to see where the latest earthquake was, check out their projects. But you don’t need even a Raspberry Pi to see where the earthquakes are, thanks to a Hackaday Prize entry all you need is a Twitter account.

Thanks to [Rich Cochran] aka [AG6QR] for the tip!

Electrostatically Accelerated Ping-Pong Ball Travels the Circuit

There is a special breed of hardware hacker whose playground lies in the high voltage arena. Their bench sizzles with the ozone and plasma of Tesla coils, and perhaps it’s best not to approach it without a handy fluorescent light tube to sniff for unseen hazards. There are many amazing things that can come of these experiments, and fortunately for those of us who lack the means or courage to experiment with them there are many YouTube videos to satisfy our curiosity.

One such comes from [Plasma channel], in the form of a table-top ping-pong ball accelerator. It lacks impressive sparks  but makes up for it in scientific edification, because it uses static electricity to send a conductive-paint-coated ping-pong ball spinning round the inside of a curved glass bowl. It does this using alternate positive and negatively charged strips of aluminium tape on the inside of the bowl, each of which charges the ball as it rolls over it, then giving it a bit of repulsive force to keep it spinning. His power comes from a couple of small Wimshurst machines, but no doubt other similar generators could be used instead.

The whole is an entertaining if a little hazardous talking point, and a fun weekend build. The parts are easy enough to find that you might even have them to hand. If continued electrostatic diversion floats your boat, you might like to read our recent excursion into the subject.

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Scanning Tunneling Microscope Packs the Bits

We don’t usually think of a microscope as an active instrument, but researchers in Canada have used a scanning tunneling microscope to remove or replace single hydrogen atoms from the surface of a hydrogen-passivated silicon wafer. If the scientific paper is too much to wade through, there’s an IEEE Spectrum article and a video that might run on the 6 o’clock news below.

As usual with these research projects, there is good news and there is bad news. The good news is that — in theory — a memory device made using hydrogen lithography could store 138 terabytes per square inch. That’s enough, apparently, to store the entire iTunes catalog on a quarter. The bad news? Well, right now this takes exotic lab equipment at very low temperatures and pressures.

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Junk Bin Spin Coater uses Modded Case Fan

We’ve all been there: you need a specific tool or gadget to complete a project, but it’s not the kind of thing you necessarily want to fork over normal retail price for. It could be something you’re only going to use once or twice, or maybe you’re not even sure the idea is going to work and don’t want to invest too much money into it. You cast a skeptical towards the ever-growing pile of salvaged parts and wonder…

Inspiration and a dig through the junk bin is precisely how [Nixie] built this very impressive spin coater for use in his ongoing homemade semiconductor project. If you’ve never had first hand experience with a spin coater, don’t worry, not many people have. Put simply, it’s a machine that allows the user to deposit a thin layer of material on a disc by way of centrifugal force. Just place a few drops in the center of the disc, then spin it up fast enough and let physics do the rest.

[Nixie] only needs to spin up a fairly tiny disc, and realized the hub of a 40x40mm brushless case fan was just about the perfect size. A quick pass through the lathe stripped the hub of its blades and faced off the front. Once he found a tube that was the exact same diameter of the fan’s axle, he realized he could even use a small vacuum pump to hold his disc in place. A proper seal is provided by 10 and 16 mm OD o-rings, installed into concentric grooves he machined into the face of the hub.

With a way to draw a vacuum through the hub of the spinner he just needed the pump. As luck would have it, he didn’t have to wait for one to make the journey from China, as he had one of those kicking around his junk bin from a previous project. The only thing he ended up having to buy was the cheap PWM fan controller which he mounted along with the modified fan to a piece of black acrylic; producing a fairly professional looking little piece of lab equipment. Check out the video after the break for a brief demonstration of it in action.

This isn’t the first specialized piece of gear [Nixie] has produced in his quest for DIY chips. We’ve previously covered his DIY tube oven as well as his vacuum chamber complete with magnetically controlled manipulator arm.

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Frozen Rat Kidney Shipping Container

The biggest allure of 3D printing, to us at least, is the ability to make hyper-personalized objects that would otherwise fall through the cracks of our mass-market economy. Take, for instance, the Frozen Rat Kidney Shipping Container, or maybe some of the less bizarro applications in the US National Institute of Health’s 3D Print Exchange.

The Exchange is dominated, at least in terms of sheer numbers, by 3D models of proteins and other biochemical structures. But there are two sections that will appeal to the hacker in you: prosthetics and lab equipment. Indeed, we were sent there after finding a nice model of a tray-agitator that we wanted to use for PCB etching. We haven’t printed one yet, but check out this flexible micropositioner.

While it’s nowhere near as comprehensive a resource as some other 3D printing model sites, the focus on 3D printing for science labs should really help those who have that particular itch to find exactly the right scratcher. Or a tailor-made flexible container for slicing frozen rat kidneys. Whatever you’re into. We don’t judge.

Man with skull image: [jaqtikkun]

Changing Color Under Pressure

When you saw the picture for this article, did you think of a peacock’s feather? These fibers are not harvested from birds, and in fact, the colors come from transparent rubber. As with peacock feathers, they come from the way light reflects off layers of differing materials, this is known as optical interference, and it is the same effect seen on oil slicks. The benefit to using transparent rubber is that the final product is flexible and when drawn, the interference shifts. In short, they change color when stretched.

Most of the sensors we see and feature are electromechanical, which has the drawback that we cannot read them without some form of interface. Something like a microcontroller, gauge, or a slew of 555 timers. Reading a single strain gauge on a torque wrench is not too tricky, but simultaneously reading a dozen gauges spread across a more complex machine such as a quadcopter will probably require graphing software to generate a heat map. With this innovation it could now be done with an on-board camera in real-time. Couple that with machine learning and perhaps you could launch Skynet. Or build a better copter.

The current proof-of-concept weaves the fibers into next-generation bandages to give an intuitive sense of how tightly a dressing should be applied. For the average first-aid responder, the rule is being able to slide a finger between the fabric and skin. That’s an easy indicator, but it only works after the fact whereas saying that the dressing should be orange while wrapping gives constant feedback.

Extracting Water from Fog

Most of us take it for granted that water is as close as your kitchen tap. But that’s not true everywhere. Two scientists at MIT have a new method for harvesting water from fog, especially fog released from cooling towers such as those found from power plants. It turns out, harvesting water from fog isn’t a new idea. You typically insert a mesh into the air and collect water droplets from the fog. The problem is with a typical diameter of 10 microns, the water droplets mostly miss the mesh, meaning they typically extract no more than 2% of the water content in the air.

The team found two reasons for the low efficiency. Water clogs the mesh openings which can be somewhat mitigated by using coated meshes that shed water quickly. Even in the lab that only increases the yield to about 10%. The bigger problem, though, is basically only some of the droplets hit the mesh, and even those that do may not stick because of drag. Fine meshes can help but are harder to make and have low structural integrity. Their solution? Inject ions into the fog to charge the water droplets and impart the opposite charge on the mesh.

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