A Vacuum Tube and Barbecue Lighter X-Ray Generator

A certain subset of readers will remember a time when common knowledge held that sitting too close to the TV put you in mortal peril. We were warned to stay at least six feet back to avoid the X-rays supposedly pouring forth from the screen. Nobody but our moms believed it, so there we sat, transfixed and mere inches from the Radiation King, working on our tans as we caught up on the latest cartoons. We all grew up mostly OK, so it must have been a hoax.

Or was it? It turns out that getting X-rays from vacuum tubes is possible, at least if this barbecue lighter turned X-ray machine is legit. [GH] built it after playing with some 6J1 rectifier tubes and a 20-kV power supply yanked from an old TV, specifically to generate X-rays. It turned out that applying current between the filament and the plate made a Geiger counter click, so to simplify the build, the big power supply was replaced with the piezoelectric guts from a lighter. That worked too, but not for long — the tube was acting as a capacitor, storing up charge each time the trigger on the lighter was pulled, eventually discharging through and destroying the crystal. A high-voltage diode from a microwave oven in series with the crystal as a snubber fixed the problem, and now X-rays are as easy as lighting a grill.

We have to say we’re a wee bit skeptical here, and would love to see a video of a test. But the principle is sound, and if it works it’d be a great way to test all those homebrew Geiger counters we’ve featured, like this tiny battery-powered one, or this one based on the venerable 555 timer chip.

Reverse Engineer An X-Ray Image Sensor

If you think of a medical x-ray, it is likely that you are imagining a photographic plate as its imaging device. Clipped to your tooth by your dentist perhaps, or one of the infamous pictures of the hands of [Thomas Edison]’s assistant [Clarence Madison Dally].

As with the rest of photography, the science of x-ray imaging has benefited from digital technology, and it is now well established that your hospital x-ray is likely to be captured by an electronic imaging device. Indeed these have now been in use for so long that their first generation can even be bought by an experimenter for an affordable sum, and that is what the ever-resourceful [Niklas Fauth] with the assistance of [Jan Henrik], has done. Their Trophy DigiPan digital x-ray image sensor was theirs for around a hundred Euros, and though it’s outdated in medical terms it still has huge potential for the x-ray experimenter.

The write-up is a fascinating journey into the mechanics of an x-ray sensor, with the explanation of how earlier devices such as this one are in fact linear CCD sensors which track across the exposed area behind a scintillator layer in a similar fashion to the optical sensor in a flatbed scanner. The interface is revealed as an RS422 serial port, and the device is discovered to be a standalone unit that does not require any commands to start scanning. On power-up it sends a greyscale image, and a bit of Sigrok examination of the non-standard serial stream was able to reveal it as 12-bit data direct from the sensor. From those beginnings they progressed to an FPGA-based data processor and topped it all off with a very tidy power supply in a laser-cut box.

It’s appreciated that x-rays are a particularly hazardous medium to experiment with, and we note from their videos that they are using some form of shielding. The source is a handheld fluoroscope of the type used in sports medicine that produces a narrow beam. If you remember the discovery of an unexpected GameBoy you will be aware that medical electronics seems to be something of a speciality in those quarters, as do autonomous box carriers.

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A Perfect Rose, a Stepper, an X-Ray Machine, and Thee

The Day of Compulsory Romance is once more upon us, and in recognition of that fact we submit for your approval an alternative look at one of the symbols of romantic love: an X-ray of a rose.

Normally, diagnostic X-rays are somewhat bland representations of differential densities of the tissues that compose various organs and organ systems, generally rendered in shades of gray. But [Linas K], a physicist with time to kill and access to some cool tools, captured the images in the video below not only in vivid color, but as a movie. The imaging side of the project consists of a low-power X-ray tube normally used for non-clinical applications and a CMOS sensor panel. The second video shows that [Linas] did an impressive upgrade on the X-ray controller, rolling his own from an FPGA. This allowed him to tie in a stepper motor to rotate the rose incrementally while taking images which he stitched together in post.

Watching the interior structure of the flower as it spins is fascinating and romantic in its own right, for certain subsets of romance. And really, who wouldn’t appreciate the work that went into this? But if you don’t have access to X-ray gear, fear not — a lovely Valentine’s gift is only a bottle of ferric chloride away.

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The Physics of Healing: Radiation Therapy

Few days are worse than a day when you hear the words, “I’m sorry, you have cancer.” Fear of the unknown, fear of pain, and fear of death all attend the moment when you learn the news, and nothing can prepare you for the shock of learning that your body has betrayed you. It can be difficult to know there’s something growing inside you that shouldn’t be there, and the urge to get it out can be overwhelming.

Sometimes there are surgical options, other times not. But eradicating the tumor is not always the job of a surgeon. Up to 60% of cancer patients will be candidates for some sort of radiation therapy, often in concert with surgery and chemotherapy. Radiation therapy can be confusing to some people — after all, doesn’t radiation cause cancer? But modern radiation therapy is a remarkably precise process that can selectively kill tumor cells while leaving normal tissue unharmed, and the machines we’ve built to accomplish the job are fascinating tools that combine biology and engineering to help people deal with a dreaded diagnosis.

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LEGO Components Under X-Ray

[Nico71] works for a company that makes industrial CT scanners. These x-ray machines look inside a piece of equipment, allowing operators to verify assembly and to inspect for material integrity. It also allowed [Nico71] the opportunity to scan a LEGO servo he had lying around, and which no longer worked. The resulting images look fantastic, and really allow you to look into a closed system and pick apart how it works or why it’s not working. In this case, you can see one of the wires has been damaged.

[Nico71] plans to scan a bunch of LEGO components, comparing (for instance) official LEGO products with shanzhai knockoffs. Which is better constructed? It’s one thing to have thinner or cheaper plastic, or a lower grade of steel, but how is the part engineered?

We’ve covered a surprising amount of CT goodness on Hackaday, including this process for turning a CT scan into a 3D print and a post on improving a homebrew CT scanner. Continue reading “LEGO Components Under X-Ray”

Retrotechtacular: Examining Music in 1950’s Russia

If you had told 12-year-old me that one day I would be able to listen to pretty much any song I wanted to on demand and also pull up the lyrics as fast as I could type the artist’s name and part of the title into a text box, I would have a) really hoped you weren’t kidding and b) would have wanted to grow up even faster than I already did.

The availability of music today, especially in any place with first world Internet access is really kind of astounding. While the technology to make this possible has come about only recently, the freedom of music listening has been fairly wide open in the US. The closest we’ve come to governmental censorship is the parental advisory sticker, and those are just warnings. The only thing that really stands between kids’ ears and the music they want to listen to is parental awareness and/or consent.

However, the landscape of musical freedom and discovery has been quite different in other corners of the world, especially during the early years of rock ‘n roll. While American teens roller skated and sock-hopped to the new and feverish sounds of Little Richard and Elvis Presley, the kids in Soviet Russia were stuck in a kind of sonic isolation. Stalin’s government had a choke hold on the influx of culture and greatly restricted the music that went out over the airwaves. They viewed Western and other music as a threat, and considered the musicians to be enemies of the USSR.

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To See Within: Making Medical X-rays

I was a bit of a lost soul after high school.  I dabbled with electrical engineering for a semester but decided that it wasn’t for me – what I wouldn’t give for a do-over on that one. In my search for a way to make money, I stumbled upon radiologic technology – learning how to take X-rays. I figured it was a good way to combine my interests in medicine, electronics, and photography, so after a two-year course of study I got my Associates Degree, passed my boards, and earned the right to put “R.T.(R) (ARRT)” after my name.

That was about as far as that career went. There are certain realities of being in the health care business, and chief among them is that you really have to like dealing with the patients. I found that I liked the technology much more than the people, so I quickly moved on to bigger and better things. But the love of the technology never went away, so I thought I’d take a look at exactly what it takes to produce medical X-rays, and see how it’s changed from my time in the Radiology Department.

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