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.
Some people aren’t too crazy about the rush of RFID enabled credit & debit cards, and the problem is, you don’t really have a choice what card you get if the bank sends you a new one! Well if you really don’t like this on your card for whatever reason, it’s pretty easy to disable.
[James Williamson] recently got a new debit card with RFID technology — the problem is it was messing with his access card at work, the readers would beep twice, and sometimes not work. He decided to disable it because of this and that he didn’t really use the tap to pay feature, nor was he completely convinced it was as secure as the bank said.
Since these RFID chips use antennas made of copper wire, he could have just started slicing his card with a knife to break the antenna — but, since he has access to a CT scanner, he thought he’d scan it to figure out where everything was.
Simply make a small notch in the edge of your card, or snip off one of the corners. This breaks the antenna and prevents power to the chip when held near a reader — though if you don’t have access to a CT scanner you might want to double-check next time you buy something!
Now there is another side to this — maybe you actually like the whole tap to pay thing, well, if you wanted to you could get a supplemental card, dissolve it in acetone, and then install the RFID chip into a finger ring for Jedi-like purchasing powers!
It’s not every day one of the builds on Hackaday gets picked up by a big-name publication, and it’s even rarer to see a Hackaday contributor grace the pages of an actual print magazine. Such is the case with [Adam Munich] and his home-built x-ray machine.
We first saw [Adam]’s x-ray machine at the beginning of this year as an entry for the Buildlounge/Full Spectrum laser cutter contest. [Adam] won the contest, landed himself a new laser cutter, and started writing for Hackaday. Now that [Adam] is gracing the pages of Popular Science, we’re reminded of the story of Icarus, flying too close to the sun.
[Adam]’s x-ray machine is built around a Coolidge tube, the same type of vacuum tube found in dental x-ray machines. The device is housed in two suitcases – one used as a control panel and graced with beautiful dials and Nixies, the other housing the Coolidge tube and power supply. Proper x-ray images can be taken by pointing a camera at the scintillation screen, allowing [Adam] to see inside hard drives and other inanimate objects.
Sure, it’s a build we’ve seen before but it’s still very cool to see one of Hackaday’s own get some big name recognition.
We know that most of you will have no reason to ever make a miniature X-ray tube. However, we also know that many of you will find this video mesmerizing like we did. [Glasslinger] does a fantastic job of explaining the entire process of creating the mini x-ray tube from, procuring the uranium glass and tungsten stem, creating the filament from scratch, all the glass work, and the testing.
Admittedly, most of us here at hackaday won’t go any further than admiring the craftsmanship, though we’re curious to see what [Adam Munich] has to say when he sees this story.
If you enjoyed the tube construction in the video, be sure to check out [Glasslinger’s] other videos. He makes all kinds of tubes in his shop and usually shares so much information along the process that each one has useful information beyond that particular project. Another crazy part is that he has made most of his own tools, including his glass lathe.
We really shouldn’t have to point out that X-Rays are dangerous. Don’t mess with them unless you have researched how to do it safely.
[Linas] built himself an x-ray generator for a scholarship contest. We assume this wasn’t enough of a challenge for [Linas] because after the x-ray generator was done, he used his project to model objects in 3D (Google Translate link). It’s an amazing build, leaving us feeling sorry for the guy that came in second place to the home-made CT scanner.
The theory behind a CT scanner is fairly simple – take a series of x-rays of an object around an axis of rotation. From there, it’s a fairly simple matter to digitize the x-ray images to produce a 3D model. The hard part is building the x-ray generator. [Linas] used directional x-ray tubes, a few power supplies and from what we can gather x-ray film instead of a CCD sensor. The film was scanned into a computer and reassembled to get a 3D image.
[Linas] doesn’t seem too keen on giving away the schematics for his build to any old joker on the Internet because of the high voltage and radiation components of his build. Still, it’s an amazing build.
Check out the YouTube demo of [Linas]’s CT scanner imaging an old computer mouse and a reconstruction of the same data done in MATLAB after the break.
Continue reading “Build your own CT scanner”
Researchers at the University of Utah have been able to detect movement in a room based on variations in wireless signals. Accurate to about a meter, they are using a 34 node wireless network to do their sensing. As a person moves, they change the signals, and can therefore be detected. They state one possible application being rescue workers deploying multiple wireless nodes around a building to find people located inside.