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Thread: Surface mount soldering magnification with a used $50 document camera?

  1. #1

    Default Surface mount soldering magnification with a used $50 document camera?

    Working on old computers with equally old eyes can be tough, working on SMD boards with old eyes is even tougher. This document camera was recommended to me by someone on Twitter and I was surprised how well it works.

    In this this video we take a look at repurposing a second-hand document camera for soldering surface mount circuit boards. While these cameras are intended for projecting documents in classrooms and board rooms, we’ll see how this $50, 10+ year old model works for surface mount PCB soldering.

    We’ll solder up some surface mount boards which use mid-sized parts and then inspect out work. Then we will also take a look at a through hole board with very tight spacing to see if we can spot the problem it has. Finally, we finish off looking at a modern surface mount board that uses very tiny parts to see what they look like under the document camera.

    Can we use an old document camera for SMD work? Join in as we find out.

    https://youtu.be/X-CDbCHIR7U

  2. #2
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    This is a great idea, Jeff. I'll be trying it out myself soon. I've just now ordered the same model you demonstrate in your video, also used like yours.

    I've had limited success using a cheap (but more costly than your used document camera) small camera and LCD unit, like this one:
    camera-w-lcd.png
    It's worked for me for the few times I couldn't get by with an optivisor and magnifying light, but it's difficult to use as it has very small field of view, shallow depth of field, and not much space between the camera and PCB I'm inspecting or soldering components on.

    Thank you so much for sharing this idea!

    Ron

  3. #3
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    I'm still using my old B&L Stereozoom scope. There's a certain immediacy to having a stereo view of the real thing. It's old enough that it doesn't have the "third eye" for camera attachment, however--something I wish at times that it had. I do have the clear filter on it, however to keep soldering smoke out of the objective.
    Last edited by Chuck(G); January 9th, 2021 at 08:28 PM.

  4. #4

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    I have to agree with Chuck(G).

    To acquire an image to an optical sensor and reproduce that digitally via a camera and a display is a poorer way to image a pcb with surface mount parts, than direct optical methods. Why not look directly at it with a binocular microscope that has a good light source. These sorts of things used to be crazy expensive, because of the cost of the precision optics, but now they are very cheap, one example:

    https://www.ebay.com/itm/Binocular-S...Cclp%3A2334524

    If you pay just a little more you can get one of these:

    https://www.ebay.com/itm/Stereo-Indu....c100005.m1851


    So putting another interface "in the way" between you and what you want to look at is not really very clever in my opinion.

    Every week at work, I look via a high precision Zeiss microscope with a stereo view and excellent lighting to perform cataract surgery. There has been a push by some companies lately to convert that to a camera view with a 3D VDU. I could never see the point of this when I can already perfectly see what I am doing, with the precision optical interface.
    Last edited by Hugo Holden; January 10th, 2021 at 03:18 AM.

  5. #5
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    I will agree that, if your eyes are good enough, an optical instrument is superior.

    But having said that, my eyes aren't good enough. I was born with strabismus, and developed amblyopia. I had surgery for this at three and a half years of age, but the surgeon overcompensated. So I am stereoblind, and even though I've tried some of the techniques in "Fixing My Gaze: A Scientist's Journey Into Seeing in Three Dimensions" by Susan R. Barry I've not had much success, no doubt due to severe myopia in one eye and mild presbyopia in the other; my two eyes see things at different sizes in addition to having almost no depth perception.

    My myopic eye is my dominant eye, and I'm so myopic that simply removing my glasses and moving things closer is basically a 3x magnification; when I was a bit younger my vision was sharp enough to check fiber optic cleave quality without a magnifier. But everything beyond about a foot from my face is blurry.

    So something like this is very useful to me.
    Last edited by lowen; January 10th, 2021 at 06:03 AM.
    --
    Thus spake Tandy Xenix System III version 3.2: "Bughlt: Sckmud Shut her down Scotty, she's sucking mud again!"

  6. #6
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    After cataract surgery, my distance vision improved greatly, but anything up close requires help. On top of my system here, I have a bowl of reading glasses of varying strengths and hanging in my shop, I have OptiVisors of varying strengths. For really small stuff, I use the microscope or a compound loupe. One thing that the opto-meds don't tell you is that even after surgery, your visual acuity slowly declines with age. It's hard to describe, but everything is in focus, but it's harder to find detail. To compound the problem I have rather severe CN, so seeing things has always been something of a challenge to me.

    That being said, I can still work on fine-pitch SMT with little difficulty.

    A hint to those needing spectacles: shell out for real glass lenses--the clarity and color definition is worth it--at least to me, it is. Plastic is fine for backup, but glass is still king in my book.

  7. #7

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    Quote Originally Posted by lowen View Post
    But having said that, my eyes aren't good enough. I was born with strabismus, and developed amblyopia. I had surgery for this at three and a half years of age, but the surgeon overcompensated. So I am stereoblind
    Below the age of about 7 or 8 the brain is "plastic" and the connections with the eyes to the visual brain are still being formed. If there is anything wrong with an eye, say it is turned in or out, or it is out of focus, the connections to the brain become unlinked and the vision is suppressed, the other eye takes the connections and becomes dominant.

    Once the concrete sets on this after about the age of 8 or 10 it cannot be reversed. The eye that now has blunted vision is called Amblyopic. But it is no longer a problem that "belongs to the eye". So if a surgeon straightens a turned eye after that age (or an Optometrist re-focuses the eye with glasses), it is only "cosmetic" and has no effect at all on the quality of the sight.

    When an eye is straightened at a young age like 3, it can help, but it is not 100% the solution, because it only takes fractional angle misalignment which often remains after surgery to induce amblyopia. The way the problem is reversed is to patch the good eye which strengthens up the connections with the turned or out of focus eye. So the failure of treatment of amblyopia is not failure of surgery, it is failure of adequate patching in childhood.

    One very interesting thing is, if a person has had poor vision in one eye since childhood and has amblyopia, the good eye so to speak has much more input to the visual system compared to a normal case when each eye has equal input. Because of this the brain can synthesize a type of stereo vision via the one eye which "normals" do not have, which appears almost as good as binocular stereo vision, some famous sports and ball game players have had amblyopia and function at a very high level computing the position of moving objects without difficulty. This does not happen in a mature visual system, say if a person suddenly loses vision in one eye, they then have difficulties with stereo vision and depth perception.

  8. #8
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    Quote Originally Posted by Hugo Holden View Post
    Below the age of about 7 or 8 the brain is "plastic" and the connections with the eyes to the visual brain are still being formed. If there is anything wrong with an eye, say it is turned in or out, or it is out of focus, the connections to the brain become unlinked and the vision is suppressed, the other eye takes the connections and becomes dominant.

    Once the concrete sets on this after about the age of 8 or 10 it cannot be reversed.
    I sure appreciate your expertise in this; I've lived with these effects all my life, and it's always a bit comforting to have professional confirmation of these effects.

    But the lady I mentioned before, Susan R. Barry, was successful at retraining her brain in her late 40's, thus her book. She has a Ph D from Princeton and is a full professor of neurobiology at Mount Holyoke College. https://en.m.wikipedia.org/wiki/Susan_R._Barry

    That's why I mentioned her book and the exercises that worked for her. They call her "Stereo Sue."
    --
    Thus spake Tandy Xenix System III version 3.2: "Bughlt: Sckmud Shut her down Scotty, she's sucking mud again!"

  9. #9

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    Quote Originally Posted by lowen View Post
    I sure appreciate your expertise in this; I've lived with these effects all my life, and it's always a bit comforting to have professional confirmation of these effects.

    But the lady I mentioned before, Susan R. Barry, was successful at retraining her brain in her late 40's, thus her book. She has a Ph D from Princeton and is a full professor of neurobiology at Mount Holyoke College. https://en.m.wikipedia.org/wiki/Susan_R._Barry

    That's why I mentioned her book and the exercises that worked for her. They call her "Stereo Sue."
    There is "some" retraining or perhaps adaptation that can take place in adulthood, it is just not nearly as powerful as when the system is plastic. One example of this is, if a person suddenly loses sight in one eye, in most countries, it is not legal for them to drive, until they have had a 3 month adaptation period. So the concrete so to speak, is still a little soft. Also neuroplasticity effects do occur after brain cell injury too.

    There is also an interesting curio about the way the brain processes stereo vision in a "normal". When looking at a flat surface, the brain knows it is flat and it suppresses depth perception to some extent. It was noticed many years ago at the dawn of Television. If the screen was viewed with one eye covered after some minutes the apparent depth perception in the image increases ! Oddly this effect, reported in Television related documentation, never made it to the standard Physiology textbooks on the Eye. But it gives an inkling of the way depth perception is re-computed in those with only clear vision via one eye.

  10. #10
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    Quote Originally Posted by Hugo Holden View Post
    Below the age of about 7 or 8 the brain is "plastic" and the connections with the eyes to the visual brain are still being formed. If there is anything wrong with an eye, say it is turned in or out, or it is out of focus, the connections to the brain become unlinked and the vision is suppressed, the other eye takes the connections and becomes dominant.

    Once the concrete sets on this after about the age of 8 or 10 it cannot be reversed. The eye that now has blunted vision is called Amblyopic. But it is no longer a problem that "belongs to the eye". So if a surgeon straightens a turned eye after that age (or an Optometrist re-focuses the eye with glasses), it is only "cosmetic" and has no effect at all on the quality of the sight.

    When an eye is straightened at a young age like 3, it can help, but it is not 100% the solution, because it only takes fractional angle misalignment which often remains after surgery to induce amblyopia. The way the problem is reversed is to patch the good eye which strengthens up the connections with the turned or out of focus eye. So the failure of treatment of amblyopia is not failure of surgery, it is failure of adequate patching in childhood.

    One very interesting thing is, if a person has had poor vision in one eye since childhood and has amblyopia, the good eye so to speak has much more input to the visual system compared to a normal case when each eye has equal input. Because of this the brain can synthesize a type of stereo vision via the one eye which "normals" do not have, which appears almost as good as binocular stereo vision, some famous sports and ball game players have had amblyopia and function at a very high level computing the position of moving objects without difficulty. This does not happen in a mature visual system, say if a person suddenly loses vision in one eye, they then have difficulties with stereo vision and depth perception.
    Yes, I was diagnosed with this condition when I first went to school at age 5 or 6 and wore a patch for a couple of years. Didn't do much good and now in my 70's I still have a "good eye" plus a "bad eye" that can't be corrected very well. I've used loupes for years working on watches and electronics plus have a stereo scope I use when needed. Also, own more than a few head mounted magnifiers from Harbor Freight. I've also played around with a $25-$30 digital single lens camera based scope tied to my computer, but for soldering I never got good at looking one place while soldering in another place. Magnifiers for most work and whatever works for the tiny stuff.
    Crazy old guy with a basement full of Pentium 1 laptops and parts

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