• Nothing still works! And I'm kind of at a loss.

    Ahron Wayne4 days ago 0 comments

    Things that are purchased as "broken/for parts only" on ebay might be broken/for parts only.

    Here are five examples:

    There's the original detector I bought for a hundred bucks, which a functioning CT machine revealed had a smashed detector. 

    There's the replacement one I got from the same seller for just fifty bucks, which CT revealed had busted bond wires. (Theoretically fixable but whaaaaat?) 

    Then I got two more from this really nice guy on ebay (thanks conundrum)! These are merely probably broken. They at least connect to USB unlike the other one:

    I haven't checked these with CT, but at least one of them is probably broken on account of the uniform static it gives off in the images... 

    As opposed to working units which give off this kind of static. 

    This is according to https://nucwiki.org/wiki/index.php/Gendex_GXS700 which is a great source for all things that will get you put on a watchlist. 

    I have no way to check for sure though, because: 

    My source arrived, and is broken too! 

    Again, this is a hamamatsu photoionizer, as used by the very smart and also already totally built a CT machine like this Andrew Seltzman:

    The video also shows off the code I was trying to use to run my sensors. From Mr. Seltzman himself, I also got the pinout for the photoionizer:

    I connect 12 volts to 12v, ground to ground, and got a modest current draw of a few dozen miliamps. I checked the D1 line it and it was in fact at 5v. But when I tried connecting the ILK line to said 5V, no rise in current, no signal on my geiger counter, nothing! 

    And I checked ALT and it was always zero too. This was sad. So I follow the instruction on the side.. 

    and I opened it up and there was a guy with a big frown and a big yellow busted capacitor. 

    So, yeah. Project not going great. If you stumble upon this and it was my last entry, you can make your own conclusions about my stick-toitive-ness. 

    Happy Thanksgiving! 

  • Nothing worked as it should! And there are more parts on the way

    Ahron Wayne10/14/2022 at 00:36 0 comments

    Remember my smashed detector? So that ionizer I bought also turned out to be not the photoionizer that also produces x-ray variety. 

    It's pretty clever still though. Instead of an x-ray source, it has a high voltage connected to these rails which are separated by spikes. The spikes are too far to produces sparks, but close enough to ionize the air between them somewhat. I guess. The fan blows it away and the whole thing is put together durably and even has a little spinable brush that cleans the needles for you.

    No x-rays though unfortunately... 

    so I won this for a bit less than I thought I would and now it's my replacement. I know the x-rays are soft and pretty weak, but it's so small and it would be so cute together with my tinyass detector. When I get one that works...


    And for that I'll hopefully have to thank a fellow ebayer, the one who left the only legitimate feedback for the smashed one I bought. I sent him a message and he mentioned it seemed to work but he stopped the project and I pestered him for it and he actually made a listing for me! Turned out to be two actually. Score! 

    I also have another one coming from the original seller, for 50% off. So I will have a combo of 4 of the same model, at least one of which has smashed cmos. Should be able to put them all together and get at least one to work, right? 

  • Entry 0: Up to speed

    Ahron Wayne10/01/2022 at 18:36 0 comments

    I don't have a DIY CT scanner yet. But as mentioned in the description, my plan is to use a cheap, small detector and source, motorization, and software to hack it all together and make it better than the sum of the parts. 

    It is no coincidence that this is similar to the LadyBug project. Trade time of scan for money and let the technology work while you sleep. 

    I started by purchasing a broken, cheap x-ray detector and hoping I would get lucky:

    These things are meant for single tooth measurements and were like $7000 when new. My hope was I'd get one that worked out of the box, or barring that, was fixable -- maybe like a cord issue. 

    Closer inspection of the reviews would have revealed something suspicous. The first review was genuine but the subsequent ones, not so much:

    Works great for apple TV!

    A couple weeks go by and it's in my hands! cool! There's a cesium iodide scintillator, CMOS sensor, lead sheet and electronics in here! I plug it into my computer and hopefully hear the boop da doop that USB devices do when they're connected...

    nothing. 

    Squeeze and wiggle the wires, still nothing. Believe it or not, I took this as good news: I thought this probably meant that the problem was with the wiring, not the actual sensor. I know how to solder and as long as I could confirm that was the issue, it wouldn't be a tough fix.

    Luckily, as mentioned in the description, I do CT scanning for a living already. 

    So I fixture it up with foam (mostly transparent to x-rays) "good enough" to look at my regions of interest...


    toss it in the machine, and setup a scan.

    Now, I was expecting to pore over the result looking over a broken wire somewhere. But what I saw was a bit more obvious. And not so good. 

    Well.. there's your problem. That's the CMOS sensor array. Looks like someone bit down a bit too hard. No fixing that. Guy on ebay said no returns, he'd give me another one at half price. I'm considering it. 


    So let's focus for a second on the second big component: The x-ray source. What to use? I did some perusing for handheld dental ones and old tubes and when watching a video by andrew seltzman about the Dexis detectors learned something interesting. New static eliminators for industry use have photoionizers in them that work by, you guessed it, generating (soft) x-rays. This turned out to be the cheapest source by far for getting started and testing at least.  

    Left without a functioning detector for now, I remembered that like 10 years ago, my grandfather, a dentist, gave me some little pieces of x-ray film in the exact size and shape of my shattered detector (not a coincidence). Sure enough, they were still there --- and now I have a way to see if my ionizer indeed produces soft x-rays.

    Thanks Pupa!