Portable, DIY Radiography

[Matt] has a background in radiation, electronics, and physics, which means building a device to generate X-rays was only a matter of time. It’s something not everyone should attempt, and [Matt] discourages anyone from attempting anything like this, but if you’re looking for a project with a ‘because it’s there’ flair to it, building your own X-ray machine can be a fun and rewarding project.

Despite being scary and mysterious, X-rays are a rather old technology that date back to some of the first purposeful experiments in electronics. Most X-ray devices today are built around the same parts they were 100 years ago, namely, a Coolidge tube. Apply a high enough voltage to the Coolidge tube and electrons whizz from cathode to anode, and slam into a heavy metal target. This produces Bremsstrahlung radiation – breakingbraking X-rays – that can be directed to film or an X-ray intensifier screen that fluoresces in visible light when being struck by X-rays.

Aside from a cheap Coolidge tube, [Matt] constructed the rest of his X-ray generator with a voltage multiplier made out of sufficiently derated Chinese caps, a flyback transformer, and a transformer driver originally made for induction heating applications. The electronics were installed in a Tupperware container and insulated with mineral oil.

Being able to generate X-rays is one thing, viewing them is another matter entirely. For this, [Matt] is using an old X-ray intensifier screen from the 60s or 70s. This screen fluoresces blue, not the easiest color to photograph in low-light settings, but enough to capture images of the inside of tools sitting around his workbench. Following in the footsteps of [Roentgen], [Matt] also took an X-ray image of his hand. This is something he doesn’t recommend, and something he won’t do again, but it is a very cool example of what you can do with sufficient knowledge and respect for what can kill you.

Hackaday Prize Semifinalist: Low Cost Radiography

For the past year, [Adam] has been working full-time on developing a low-cost x-ray system for developing nations. He has more than 3,500 hours into the project. A few months ago, we announced the 2015 Hackaday Prize, with a theme of, ‘build something that matters.’ A low-cost x-ray would certainly matter to the two-thirds of the world’s population that does not have access to medical radiography, making this project a great entry for The Hackaday Prize.

[Adam]’s portable x-ray system consists of an x-ray tube encased in an epoxied, 3D printed enclosure filled with dialectric oil. This tube is tucked away inside a beautiful case with just a single 12VDC input and an easy to understand user manual. This is just very high voltages and x-rays, nothing [Adam] hasn’t handled (safely) before. The real trick is in the imaging, and for this, [Adam] is using a phosphor screen to turn that x-ray exposure into something visible, an off the shelf x-ray sensor, and a prism to adapt the sensor to the phosphor screen.

The results are incredible. After taking a few pictures of what he had on hand, [Adam] can see the bond wires inside the microprocessor of a calculator. That’s more than sufficient for medical imaging – the goal of the project – and cheap enough to send it to the far-flung reaches of the planet.

The 2015 Hackaday Prize is sponsored by:

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Find and Repair a 230kV 800Amp Oil-Filled Power Cable Feels Like Mission Impossible

How do you fix a shorted cable ? Not just any cable. An underground, 3-phase, 230kV, 800 amp per phase, 10 mile long one, carrying power from a power station to a distribution centre. It costs $13,000 per hour in downtime, counting 1989 money, and takes 8 months to fix. That’s almost $75 million. The Los Angeles Department of Water and Power did this fix about 26 years ago on the cable going from the Scattergood Steam Plant in El Segundo to a distribution center near Bundy and S.M. Blvd. [Jamie Zawinski] posted details on his blog in 2002. [Jamie] a.k.a [jwz] may be familiar to many as one of the founders of Netscape and Mozilla.

To begin with, you need Liquid Nitrogen. Lots of it. As in truckloads. The cable is 16 inch diameter co-axial, filled with 100,000 gallons of oil dielectric pressurised to 200 psi. You can’t drain out all the oil for lots of very good reasons – time and cost being on top of the list. That’s where the LN2 comes in. They dig holes on both sides (20-30 feet each way) of the fault, wrap the pipe with giant blankets filled with all kind of tubes and wires, feed LN2 through the tubes, and *freeze* the oil. With the frozen oil acting as a plug, the faulty section is cut open, drained, the bad stuff removed, replaced, welded back together, topped off, and the plugs are thawed. To make sure the frozen plugs don’t blow out, the oil pressure is reduced to 80 psi during the repair process. They can’t lower it any further, again due to several compelling reasons. The cable was laid in 1972 and was designed to have a MTBF of 60 years.

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Hackaday Prize Entry: A $100 CT Scanner

What do you do when you’re dad’s a veterinarian, dumped an old x-ray machine in your garage, and you’re looking for an entry for The Hackaday Prize? Build a CT scanner, of course. At least that’s [movax]’s story.

[movax]’s dad included a few other goodies with the x-ray machine in the garage. There were film cassettes that included scintillators. By pointing a camera at these x-ray to visible light converting sheets, [movax] can take digital pictures with x-rays. From there, it’s just building a device to spin around an object and a lot – a lot – of math.

Interestinly, this is not the first time a DIY CT scanner has graced the pages of Hackaday. [Peter Jansen] built a machine from a radiation check source, a CMOS image sensor, and a beautiful arrangement of laser cut plywood. This did not use a proper x-ray tube; instead, [Peter] was using the strongest legally available check source (barium 133). The scan time for vegetables and fruit was still measured in days or hours, and he moved on to build an MRI machine.

With a real source of x-rays, [movax]’s machine will do much better than anything the barium-based build could muster, and with the right code and image analysis, this could be used as a real, useful CT scanner.


The 2015 Hackaday Prize is sponsored by:

Hacklet 44 – Teardowns

Just about every hacker, maker and tinkerer out there received their early education the same way: A screwdriver in one and a discarded bit of electronics in the other. There is no better way to find out how something works than cracking it open and examining each piece.  In recent years, teardown videos have become popular on YouTube, with some of the great examples coming from users like [EEVblog], [mikeselectricstuff], and [The Geek Group]. This week’s Hacklet is all about the best teardown projects on Hackaday.io!

copierWe start with [zakqwy] and his Savin C2020 Teardown. Photocopiers (and multifunction machines) are the workhorses of the modern office. This means there are plenty of used, abused, and outdated photocopiers available to hackers. [Zakqwy] got this monster when it started misbehaving at his office. Copiers are a venerable cornucopia of motors, gears, sensors (lots and lots of breakbeam sensors) and optics. The downside is toner: it’s messy, really bad to breathe, and if you don’t wear gloves it gets down into the pores of your skin, which takes forever to get out. [Zakqwy] persevered and found some awesome parts in his copier – like an  Archimedes’ screw used to transport black toner.

wemoNext up is [Bob Blake] with Belkin WeMo Insight Teardown. [Bob] wanted a WiFi outlet, but wasn’t about to plug something in to both his power grid and his network without taking it apart first. [Bob] did an awesome job of documenting his teardown with lots of great high resolution photos – we love this stuff! He found a rather well thought out hardware design. The Insight has 3 interconnected PCBs inside. The power switching and supply circuits are all on one board. It includes slots and the proper creep distances one would expect in a design that will be carrying 120V AC mains power. A small daughter board holds an unknown chip – [Bob] is guessing it is the power sensing circuitry. A third board a tucked in at the top of the module holds the main CPU, a Ralink/MediaTek RT5350F SoC, RAM, and the all important WiFi antenna.

 

x-ray[Drhatch] took things into the danger zone with an X-ray Head Teardown. We’re not sure if [Drhatch] is a real doctor, but he does have a Heliodent MD dental X-ray head. Modern X-ray machines are generally radiation safe if they’re not powered up. Radiation isn’t the only dangers to worry about though – there are latent charged capacitors and cooling oils which may contain nasty chemicals like PCBs, among other things. [Drhatch] found some pretty interesting design decisions in his X-ray head. The tube actually fires through the cylindrical high voltage transformer. This means the transformer acts as a beam collimator, focusing the X-ray beam down like a lens. He also found plenty of lead shielding. Interestingly there are two thickness of lead in the housing. Shielding close to the tube is 1 mm thick, while shielding a bit further away is only 0.7 mm thick.

 

3phaseFinally, we have [danielmiester] with Inside a 3ph AC Motor Controller(VFD). [Daniel] tore down a Hitachi Variable-Frequency Drive (VFD) with the hopes of creating a frequency converter for a project. These high voltage, high power devices have quite a bit going on inside, so the conversion became a teardown project all its own. VFDs such as this one are used in industry to drive high power AC motors at varying speeds efficiently. As [Daniel] says, the cheaper ones are ” just really fancy PWM modules”. Handling 1.5 kW is no joke though. This VFD had a large brick of power transistors potted into its heat sink. The controller board was directly soldered to the transistors, as well as the rectifier diodes for the DC power supply. [Daniel] was doing some testing with the unit powered up, so he built a custom capacitor discharge unit from 3 C7 Christmas lights. Not only did they keep the capacitors discharged, they provided an indication that the unit was safe. No light means no charge.

Not satisfied? Want more teardown goodness? Check out our freshly minted Teardown List!

That’s about all the time we have for this week’s Hacklet. As always, see you next week. Same hack time, same hack channel, bringing you the best of Hackaday.io!

Building a miniature x-ray tube

tube

We’ve seen homemade x-ray devices and we’ve seen people making vacuum tubes at home. We’ve never seen anyone make their own x-ray tube, though, and it’s doubtful we’ll ever see the skill and craftsmanship that went into this build again.

An x-ray tube is a simple device; a cathode emits electrons that strike a tungsten anode that emits x-rays. Most x-ray tubes, though, are relatively large with low-power mammography tubes being a few inches in diameter and about 6 inches long. In his amazing 45-minute-long video, [glasslinger] shows us how to make a miniature vacuum tube, a half-inch in diameter and only about four inches long.

For those of you who love glass lathes, tiny handheld spot welders and induction heaters, but don’t want your workshop bathed in x-rays, [glasslinger] has also built a  few other vacuum tubes, including a winking cat Nixie tube. This alternate cat’s eye tube was actually sealed with JB Weld, an interesting technique if you’d ever like to make a real home made tube amp.

Airport X-ray machine teardown

airport-xray-teardown

Who has an airport carry-on X-ray machine sitting in their garage? Apparently [Mike] does, and he’s sharing the fun by posting a video teardown series that really digs into the machine’s hardware and operating system.

At this point the series includes six lengthy segments. The first episode, which you’ll find embedded after the break, starts with an external overview of the hardware. [Mike] mentions that it’s not functional at that point. He guesses that this has to do either with security settings to enable the machine (it does produce x-ray after all) or corrupt memory in an EPROM chip. The password lockout is later confirmed when he looks at a code disassembly and finds strings requesting username and password to gain access to some of the menus. The second installment involves more disassembly to figure out the passwords and gain full access to the machine. By the fourth video he’s X-raying random items from around the shop and then some.

It’s a lot to watch, but it’s exciting to see how far he gets with the rare equipment.

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