Flawed Synthetic Diamonds May Be Key For Quantum Computing

If you’ve followed any of our coverage of quantum computing, you probably know that the biggest challenge is getting quantum states to last very long, especially when moving them around. Researchers at Princeton may have solved this problem as they demonstrate storing qubits in a lab-created diamond. The actual publication is behind a paywall if you want to learn even more.

Generally, qubits are handled as photons and moved in optical fibers. However, they don’t last long in that state and it is difficult to store photons with correct quantum information. The impurities in diamonds though may have the ability to transfer a photon to an electron and back.

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Fail of the Week: The Semiconductor Lapping Machine That Can’t Lap Straight

It seemed like a good idea to build a semiconductor lapping machine from an old hard drive. But there’s just something a little off about [electronupdate]’s build, and we think the Hackaday community might be able to pitch in to help.

For those not into the anatomy and physiology of semiconductors, getting a look at the inside of the chip can reveal valuable information needed to reverse engineer a device, or it can just scratch the itch of curiosity. Lapping (the gentle grinding away of material) is one way to see the layers that make up the silicon die that lies beneath the epoxy. Hard drives designed to spin at 7200 rpm or more hardly seem a suitable spinning surface for a gentle lapping, but [electronupdate] just wanted the platter for its ultra-smooth, ultra-flat surface.

He removed the heads and replaced the original motor with a gear motor and controller to spin the platter at less than 5 rpm. A small holder for the decapped die was fashioned, and pinched between the platter hub and an idler. It gently rotates the die against the abrasive-covered platter as it slowly revolves. But the die wasn’t abrading evenly. He tried a number of different fixtures for the die, but never got to the degree of precision needed to see through the die layer by layer. We wonder if the weight of the die fixture is deflecting the platter a bit?

Failure is a great way to learn, if you can actually figure out where you went wrong. We look to the Hackaday community for some insight. Check out the video below and sound off in the comments if you’ve got any ideas.

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A Machinist’s Foray Into Jewelry Making

Machinists are expected to make functional items from stock material, at least hat’s the one-line job description even though it glosses over many important details. [Eclix] wanted a birthday gift for his girlfriend that wasn’t just jewelry, indeed he wanted jewelry made with his own hands. After all, nothing in his skillset prohibits him from making beautiful things. He admits there were mistakes, but in the end, he came up with a recipe for two pairs of earrings, one set with sapphires and one with diamonds.

He set the gems in sterling silver which was machined to have sockets the exact diameter and depth of the stones. The back end of the rods were machined down to form the post for the clutch making each earring a single piece of metal and a single gemstone. Maintaining a single piece also eliminates the need for welding or soldering which is messy according to the pictures.

This type of cross-discipline skill is one of the things that gives Hackaday its variety. In that regard, consider the art store for your hacking needs and don’t forget the humble library.

Cutting Stone with a Diamond Bit Built from Plumbing parts

Everyone’s favorite Canadian is at it again. This time, [AVE] needed to cut a large hole in a stone countertop. They making coring bits for this, but a bit this size would cost upwards of $400. Not a problem. [AvE] broke out the tools and built his own stone cutting bit.

Everything starts with a 6″ plastic pipe cap. [AvE] center drilled the cap, then threaded it. A turned down bolt makes a great arbor for this new tool. The edge of the cap was then slotted. [AvE] used a clapped out Bridgeport milling machine, but you could do the same job with a hacksaw or a Dremel tool.

The secret sauce is industrial diamonds. That’s right, this is a diamond cutting bit. [AvE] ordered 20 grams of 20-25 mesh industrial diamonds. “Mesh” defines the size of the individual diamonds — in this case around 50 microns and up.  Now, how to bind diamond and plastic? Plumber’s transition cement didn’t work – the diamonds and coating just peeled off like a sunburn. The solution turned out to be JB-Weld. A liberal coating of JB-Weld on the face of the tool, a sprinkling of industrial diamonds, and the pipe cap was ready to cut.

The cutting operation was slow, steady, and lots of cooling water. [AvE] made it most of the way through his countertop before having to refurbish his bit.

[AvE] usually is a man of many words, as can be seen in this post about his EDM machine. This time though, he gave us the silent treatment — an entire video with no words, set to classical music. It’s great seeing YouTubers step outside their comfort zone and trying something new.

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Hacked Diamond Makes Two-Atom Radio

It used to be pretty keen to stuff a radio receiver into an Altoid’s tin, or to whip up a tiny crystal receiver from a razor blade and a pencil stub. But Harvard researchers have far surpassed those achievements in miniaturization with a nano-scale FM receiver built from a hacked diamond.

As with all such research, the experiments in [Marko Lončar]’s lab are nowhere near as simple as the press release makes things sound. While it’s true that a two-atom cell is the minimal BOM for a detector, the device heard belting out a seasonal favorite from [Andy Williams] in the video below uses billions of nitrogen-vacancy (N-V) centers. N-V centers replace carbon atoms in the diamond crystal with nitrogen atoms; this causes a “vacancy” in the crystal lattice and lends photoluminescent properties to the diamond that are sensitive to microwaves. When pumped by a green laser, incident FM radio waves in the 2.8 GHz range are transduced into AM fluorescent signals that can be detected with a photodiode and amplifier.

The full paper has all the details, shows that the radio can survive extreme pressure and temperature regimes, and describes potential applications for the system. It’s far from a home-gamer’s hack at this point, but it’s a neat trick and one to watch for future exploitation. In the meantime, here’s an accidental FM radio with a pretty small footprint.

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Diamond Batteries That Last For Millennia

Like many industrialized countries, in the period after the Second World War the United Kingdom made significant investments in the field of nuclear reactors. British taxpayers paid for reactors for research, the military, and for nuclear power.

Many decades later that early crop of reactors has now largely been decommissioned. Power too cheap to meter turned into multi-billion pound bills for safely coping with the challenges posed by many different types of radioactive waste generated by the dismantling of a nuclear reactor, and as the nuclear industry has made that journey it in turn has spawned a host of research projects based on the products of the decommissioning work.

One such project has been presented by a team at Bristol University; their work is on the property of diamonds in generating a small electrical current when exposed to radioactive emissions. Unfortunately their press release and video does not explain the mechanism involved and our Google-fu has failed to deliver, but if we were to hazard a guess we’d ask them questions about whether the radioactivity changes the work function required to release electrons from the diamond, allowing the electricity to be harvested through a contact potential difference. Perhaps our physicist readers can enlighten us in the comments.

So far their prototype uses a nickel-63 source, but they hope to instead take carbon-14 from the huge number of stockpiled graphite blocks from old reactors, and use it to create radioactive diamonds that require no external source. Since the output of the resulting cells will be in proportion to their radioactivity their life will be in the same order of their radioactive half-life. 5730 years for half-capacity in the case of carbon-14.

Of course, it is likely that the yield of electricity will not be high, with tiny voltages and currents this may not represent a free energy miracle. But it will be of considerable interest to the designers of ultra-low-maintenance long-life electronics for science, the space industry, and medical implants.

We’ve put their video below the break. It’s a straightforward explanation of the project, though sadly since it’s aimed at the general public it’s a little short on some of the technical details. Still, it’s one to watch.

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Cutting Glass With CNC

Breaking a pane of glass in half is easy – just score it, break it, and after practicing a few times, you’ll eventually get it right. What about cuts that are impossible with a normal glass cutter, like radiused corners and holes? For that, you’ll need CNC. Yes, you can cut glass on a CNC machine. All you need is a diamond burr or glass drilling bit, high speeds, low feeds, and lots and lots of coolant.

Cutting glass on a CNC machine doesn’t require any spectacularly specialist equipment. [Peter] is using an $800 Chinese mini CNC engraver for this project, but that’s not the only tool that was required. A fixture for holding a glass plate was also needed, but [Peter] quickly fabricated one out of acrylic.

Cutting glass with a CNC is something we’ve seen before. [Ben Krasnow] has been using diamond burrs, high speeds, low feeds, and lots of coolant to cut mirrors so expensive you don’t even want to guess.

While [Peter] isn’t getting the perfect finish [Ben] got a few years ago, he’s still milling holes and slots in glass. He’s wondering if it could be possible to mill an aspheric lens using this technique and a special spherical burr, something that would be very interesting to see, and could be a pretty good way to rough out telescope blanks.