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Thread: DSLR Scanner: Camera Supports and Positioning

  1. #31
    Peter J. De Smidt's Avatar
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    Re: DSLR Scanner: Camera Supports and Positioning

    While my Sketchup design used cheap linear rails and bearings, they still weren't all that cheap.

    Here's a place that has materials that could be significantly less expensive: http://store.makerslide.com/
    See also: http://www.kickstarter.com/projects/...bearing-system.
    Also, to avoid lead screws, something along these lines might work: http://store.makerslide.com/index.ph...products_id=41

    For aluminum extrusions, the following place has the best prices that I've found: http://us.misumi-ec.com/
    Using these would allow someone to put together a system using very few tools.
    "Nothing will ever be attempted, if all possible objections must be first overcome." -- Samuel Johnson
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  2. #32
    joseph
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    Re: DSLR Scanner: Camera Supports and Positioning

    I've used an interlocking rack system for positioning, and it works fine.

    However, I've drawn an xy stage which could be manually controlled, using handwheels, or automated, using stepper motors, controllers, drivers, and software.

    Does anyone have any idea about how much extra the automation gear and software would cost, excluding rails and bearings, for the most cost effective system?

    Is it possible to run it from a mac, or would I need to install windows?

    Is there a GUI that could be used, or would it involve writing code in some arcane language? Because I have problems enough making myself understood in English...

    Is there someone who could take on writing an application which would have a GUI, to make the software plug and play for someone like me, who hasn't a clue? Presumably it would require start points, end points, limiters, offsets, and camera control- and the camera control might involve delays for flash recycling, and multiple exposures per frame, perhaps triggered from the computer, maybe directly attached to the camera- or does that software already exist?

    Can you make it so I can perform the whole operation by touching a screen on my iPhone, that says 'Initialize Scan' ?

  3. #33
    Peter J. De Smidt's Avatar
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    Re: DSLR Scanner: Camera Supports and Positioning

    Hi,

    We're still designing the system. This is a little slow as I started using sketchup only a couple of days ago.
    Thus we don't know the cost yet. Another big implication for this is the type of motors and drivers needed. We're _not_ making a cnc machine [made to mill wood or metal], and so we don't need 280oz motors. On the other hand, we're going to get some help with the software, and so we might need to use the electrics that our friendly contributors use.
    Another thing is we'd like to avoid using commercial lead screws. They are just too darned expensive, especially when one adds up all of the required ancillaries. I'll be running some tests today to see how regular threaded rod with DIY uhmw poly nuts works.
    It's way too early to know about the iPhone thing. Of course it could be done...but not by me.

    I"d love to see your x-y plan.
    "Nothing will ever be attempted, if all possible objections must be first overcome." -- Samuel Johnson
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  4. #34
    joseph
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    Re: DSLR Scanner: Camera Supports and Positioning

    Hi Peter -

    Well, it actually is a cnc machine, by definition, as soon as you decide to automate it ...

    Threaded rod should be just fine- I'm considering 6mm or 8mm.
    I don't have any drawings to show, I won't have until it's built, but it's very simple.
    It's often the execution that sets these things apart, not the intent- and now that the testing prototype is out of the way, I'd like to build a good looking machine, whenever I get around to it- which will take over a month, at the very least.

    Motors should be very light duty, since loading will be minimal, and If removing the requirement for micro-stepping made the thing cheaper, then I think that should be considered.

    It looks like the motion control would be an expensive option on this machine, manual positioning would be less expensive. I think the motors might remain an option on mine for a long time...

  5. #35

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    Re: DSLR Scanner: Camera Supports and Positioning

    There's no way I could afford to buy a setup with automated stepping motors nor do I have the skill or patience to build one even if provided excellent schematics/instructions. I could build one on a bilaterally sliding platform with ruled markings though.

  6. #36
    Peter J. De Smidt's Avatar
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    Re: DSLR Scanner: Camera Supports and Positioning

    People can do what they'd like. Automation aside, none of this is very difficult. I'm a very basic handyman. If someone just wants a decently high quality scanner, and they have a good digital camera, a couple of us have had systems that will do that for awhile now. Make one. If someone isn't willing to make something, well, then they can buy a normal commercial scanner. I'm not going to be making kits. What I'd have to charge to put together kits would make the system prohibitively expensive. I may eventually have a DIY article, but anyone reasonably handy could make one from the discussions and examples already given, using the materials that are best for them.

    You don't want a collimated light source? Then make a diffusion one. You want a manual slide system? That's easy. You want an automated system? The steps to accomplish that are pretty clear. You could just buy a Microcarve MV3, get an extended z-stage, which John already makes, and buy an LED light source like Peter linked to earlier. Drive the system just as a cnc person would. You want a custom UI program to run everything, and it has to be not only good but free? I'd like a good free car.

    I don't need another scanner. I have a good one. I'm doing this because the technical challenges are fun and someone might benefit down-the-road. But all of the griping, especially from people who aren't willing to try something themselves, takes all of the fun out of it.
    "Nothing will ever be attempted, if all possible objections must be first overcome." -- Samuel Johnson
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  7. #37

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    Re: DSLR Scanner: Camera Supports and Positioning

    Peter... I'm following these threads with great interest and am eager to learn as much as my feeble brain can absorb. I hope my post didn't seem negative. I didn't intend that at all. I only meant that my version would necessarily need to be very inexpensive and easy to assemble.

  8. #38
    joseph
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    Re: DSLR Scanner: Camera Supports and Positioning

    Well, free software is not so uncommon- often developed collaboratively within a community, like this one. It's not uncommon, though free cars are.

    I think you might be reading this the wrong way, the comment above mentioned considering an attempt to build one without the automated stage- which in my opinion, is a very sensible solution. Just as I have bits of timber lying around, so others might be tripping over stepper motors, and everyone brings what they can. Some skills may not be shared by everyone, and going back to re-read the beginning of the original thread, it's obvious that the vision that has got this project this far is also not a common currency. I remember the comment about building your own car, which, while not free, would be a start...

    There will be no single machine that everyone will build- though there's no reason why a set of drawings can't be made which people could use to order materials and components, and a set of instructions which could be used to aid the assembly. Free, of course. If anyone is going to go to the trouble of doing this, the design, and the results, are going to have to be pretty convincing...

  9. #39
    Peter J. De Smidt's Avatar
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    Re: DSLR Scanner: Camera Supports and Positioning

    Here's some screen grabs of the sketchup model for those without sketchup:



    "Nothing will ever be attempted, if all possible objections must be first overcome." -- Samuel Johnson
    www.peterdesmidt.com/blog

  10. #40

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    Re: DSLR Scanner: Camera Supports and Positioning

    Hi there!

    I am reading these DSLR threads with great interest. I already have a pretty good mediumformat nikon negscanner but this tickles my brain. I have built a motion controlled pan/tilt head for film that is very accurate for not too much money and I though I would try and come with some new ideas of my own to this interesting project. I have also built a 35mm slide "scanner" out of an slidesprojector that works pretty well, I tried to tackle the dust problem with a diy digital ICE with a light source alternating between visible light and infrared. Had some mixed results and some (expensive) solutions to making it work better. If infrared is of interest I could list my findings.

    If one moves the light together with the filmstrip there would be a more consistent set of tiles that is easier to assemble. Otherwise you get any un-eveness repeated on all the tiles. Particularly visible in something of solid color like a bright sky. One can also take a set of pictures of only the backlight and use it to subtract any small variations. Also simpler to build, no chance of things getting scratched or getting stuck between moving parts. Key here is making the lightsource large, very even and as light and slim as possible so it doesnt put more strain then necessary on the motors and make the contraption as small as possible.

    A posible solution to accurate automatic stitching is to take two exposures of each tile one with backlight on on another with a projected lightpattern focused on the film, a laser with a sharp grid would work well. The grid would be used for the algorithm to stitch and then the source images are replaced with the backlit epxosures.

    Looking only at the mechanical problem of moving the film in a pattern there is several cheap solutions.

    All scanners I have looked into are not driven with leadscrews but with a timing belt and two pulleys. I am not saying leadscrews are bad or anything but not a necessity.

    The best is to use linear encoders like scanners do. Then the machine knows where it is for real, but its a lot more complex and expensive to both control and build. Steppers on open circuit is a dirtcheap solution. And one can fine-tune it well, since its always doing the same pattern it is easy to find out backlash and compensate for it.

    The cheapest is using two dirt-cheap scanners and cannibalize them for parts. All steppers are more or less the same and all can easily be driven, just throw out all electronics but the motors and use the gearing, pulleys and timing belts. Maybe also the shafts and carrige are useful. Perhaps one normal size scanner and one small travelscanner combined?

    Drylin sliders or bearing slides with belts can be pretty cheap. with proper gearing and backlash compensation leadscrews is not necessary, there is backlash on leadscrews too anyway . http://www.igus.eu/wpck/default.aspx...=2370&CL=DE-en

    micro x-y mill table like this one http://www.proxxon.com/eng/html/27100.php cost around $100 and i quite easy to convert to use motors
    The y travel is only 46mm on this so maybe a bit small. But there is tons of other like this. Theres always linear stages at ebay, quite often motorized at cheap prices. http://www.ebay.com/itm/XY-X-Y-Motio...ht_3641wt_1398 this one is with servos but quite often xy tables with steppers are to be found.

    For controlling one can either use something very cheap like a arduino http://www.arduino.cc/ with easydriver stepper. http://www.schmalzhaus.com/EasyDriver/ and just hack some simple code together. Its pretty easy for this.

    Something like this moves the motor 4000 steps in one direction then 4000 in the other. This is the whole code needed.

    int dirpin = 3;
    int steppin = 12;

    void setup() {
    Serial.begin(9600);

    pinMode(dirpin, OUTPUT);
    pinMode(steppin, OUTPUT);
    }
    void loop()
    {

    int i;

    digitalWrite(dirpin, LOW); // Set the direction.
    delay(100);

    Serial.println(">>");
    for (i = 0; i<4000; i++) // Iterate for 4000 microsteps.
    {
    digitalWrite(steppin, LOW); // This LOW to HIGH change is what creates the
    digitalWrite(steppin, HIGH); // "Rising Edge" so the easydriver knows to when to step.
    delayMicroseconds(200); // This delay time is close to top speed for this
    } // particular motor. Any faster the motor stalls.

    digitalWrite(dirpin, HIGH); // Change direction.
    delay(100);

    Serial.println("<<");
    for (i = 0; i<4000; i++) // Iterate for 4000 microsteps
    {
    digitalWrite(steppin, LOW); // This LOW to HIGH change is what creates the
    digitalWrite(steppin, HIGH); // "Rising Edge" so the easydriver knows to when to step.
    delayMicroseconds(200); // This delay time is close to top speed for this
    } // particular motor. Any faster the motor stalls.

    }


    to add a function to take a picture only requires 3 lines more of code.

    Otherwise something with gui and professional drivers and controllers like geckos and a Kflop and Mach3 but it won't be very easy for a beginner. Perhaps the hardcode with Arduino is actually easier to learn and master, whatever hardware route you take. Look here for more code examples on arduino http://www.schmalzhaus.com/EasyDrive...rExamples.html

    Microstepping is nice because it takes a lot of vibrations out but it can screw you a bit on accuracy if you don't use proper gearing and try to get accuracy from the micro stepping.

    Thats all I could think of right now.

    Best regards

    Ludvig

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