Daniel Reetz, the founder of the DIY Book Scanner community, has recently started making videos of prototyping and shop tips. If you are tinkering with a book scanner (or any other project) in your home shop, these tips will come in handy. https://www.youtube.com/channel/UCn0gq8 ... g_8K1nfInQ

My camera-on-glass-platen counterweighted G2

Everything camera related. Includes triggers, batteries, power supplies, flatbeds and sheet-feeding scanners, too.
spamsickle
Posts: 596
Joined: 06 Jun 2009, 23:57

My camera-on-glass-platen counterweighted G2

Post by spamsickle » 19 Jul 2009, 19:58

Just finished scanning and converting my first book on my 2nd-generation DIY scanner, and thought I'd pause for a moment to share what I have. I grabbed ideas that people posted, and had a few ideas of my own, and I'm satisfied with how it all came together.

Someone who had previously developed a glass-platen design on this site had a dowel between the glass panes, at the vertex of the platen, to keep the sides from "spreading" at that the bottom. I hadn't considered that might be a problem before, but realized when I thought about it that it probably would be. At the same time, I wanted to avoid anything that might interfere with capturing an image all the way to the edge of the glass.

My own solution was to build a frame around the platen, that holds everything together and allows the platen to stand free on the floor (which is where I set up). This is what the whole thing looks like, in action.
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As you can (hopefully) see, I still haven't gone with preview monitors, but the LCD displays on my S5s can be rotated to give me a little real-time feedback on framing. It's necessary for me to watch these displays, too, at least until I can figure out if there's a way to turn off the "powersaver display off" function, because when the display goes off (even though the camera is still on), the manual focus goes off too, and it doesn't come back on until I turn the camera off and on, to re-load my custom settings.

These cameras allow only one custom setting (unless CHDK expands that too, I don't really know), so when I start shooting a book, I position the camera on the platen, frame the image (zooming as necessary), set white balance, manual exposure, and manual focus, and save the custom setting. The same setting SHOULD be good for the whole book.

spamsickle
Posts: 596
Joined: 06 Jun 2009, 23:57

Re: My camera-on-glass-platen counterweighted G2

Post by spamsickle » 19 Jul 2009, 20:12

The platen itself is made from picture frame, cut the "wrong way" using the mitre box I bought for this project. I'd never used a mitre box before, but I used it for several aspects of this project. By "wrong way" I just mean the corners are cut to make our platen instead of making a picture frame.

I did re-use the book cradle from my G1 scanner, but I beefed it up a bit. Previously, I just had four boards: two v-shaped boards that I rested on a base, which supported the two book-supporting boards. I stuck a little chink of wood in the vertex of the v-shaped boards, so the book-supporting boards would not be touching each other.
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I used a similar design to keep my glass panes from touching at the bottom of the platen: there's a little matchstick-sized sliver of wood on each side of the platen, at the vertex where the pieces of the picture frame come together. There is actually a little "gap" in the glass where it rests in the book, but each camera still seems to be getting a nearly complete view of its page, which is what I was hoping to accomplish.
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Securing the glass in the platen is just a few pieces of quarter-inch quarter round, glued to the side of the platen. Elmers glue doesn't really work here -- the pressure of the book against the glass caused several of these bits of wood to pop off as I was scanning. I re-glued them with superglue, and that seems to have solved the problem.

spamsickle
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Joined: 06 Jun 2009, 23:57

Re: My camera-on-glass-platen counterweighted G2

Post by spamsickle » 19 Jul 2009, 20:16

I said I beefed up the book cradle, but I didn't really say how.

I joined the two v-shaped boards together with lengths of 2x4, and rested the unit on a couple of drawer sliders.
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spamsickle
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Re: My camera-on-glass-platen counterweighted G2

Post by spamsickle » 19 Jul 2009, 20:25

I think the other design had the boards at the "top" of the platen oriented at 45 degrees to horizontal, and if I were to try building again, I'd probably try to implement something like that. I was kind of designing as I built, and using angles to join the wood, so all my boxes are box-like. It might have been easier to attach a camera properly to a 45-degree strut, but horizontal struts is what I have. Anyway, here is the solution I developed, which I wouldn't have attempted without that mitre box.
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This is what the camera mount looks like by itself.
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And a look from the rear, with the camera mounted.
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The camera mount can be positioned anywhere along the strut at the top of the platen, so "big" books can be framed as well as small books.

spamsickle
Posts: 596
Joined: 06 Jun 2009, 23:57

Re: My camera-on-glass-platen counterweighted G2

Post by spamsickle » 19 Jul 2009, 20:39

With the glass, the frame supporting the glass, the floor-standing double-strut box enclosing the frame, and the mounted cameras, the whole assembly weighs about 16 pounds.

I'd originally thought I'd attach the platen to some external mount with more drawer slides, but I realized when I got it built that I'd need counterweights to make this usable.

I thought for a couple of days about how to combine counterweights with drawer slides, but my imagination failed me. So, I decided to get rid of the drawer slides, and just go with the counterweights.

I have two 2.5-pound weights on one pair of diagonal corners, and 1 2.5-pound weight on each of the other two corners, for a total of 15 pounds.

The axles for the pulleys are all different sizes, which I bought thinking I'd use them in one of those "six-degrees-of-awesomeness" camera supports suggested over at the original Instructables site, but I never actually got around to building one of those. I'll probably take a hack saw and trim them off some day.
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The weights can be detached (they're attached to the platen legs with S-hooks), and the outer frame is made so it can be inverted over the free-standing platen to masquerade as a table when I'm not scanning books. This design doesn't come apart like my original design, and I kind of need to be able to justify leaving it taking up semi-permanent space in our living room.

One thing, the cameras need to be removed to get the memory cards out, and if the weights are still attached when I remove the cameras, the platen has a tendency to rise off the floor. This isn't a serious problem, so for the most part I just let it fly while I'm transfering the pictures to my computer, but as I say, if necessary, the weights are easily detachable.

spamsickle
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Joined: 06 Jun 2009, 23:57

Re: My camera-on-glass-platen counterweighted G2

Post by spamsickle » 19 Jul 2009, 20:45

Finally, there's the switch I got from Dan to fire the cameras at the same time.

I'd originally thought I'd attach the handle to the lower strut, but in playing around with it, that just seemed unwieldy.

I simply slipped the switch off the handle, and hold it in my hand as I raise and lower the platen, turn the pages, and take the shot.
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I got used to raising and lowering my platen with two hands and sometimes my knees with my original design, and while it might not be for everyone, it works for me.
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That's it. Now, gotta go scan some more books.

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daniel_reetz
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E-book readers owned: Used to have a PRS-500
Number of books owned: 600
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Re: My camera-on-glass-platen counterweighted G2

Post by daniel_reetz » 19 Jul 2009, 21:49

So, if I understand correctly, your platen + camera support is actually a framed, floating box that rests on the floor when not in use? Damn, that's cool.

Your camera clamp design is totally badass.

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daniel_reetz
Posts: 2786
Joined: 03 Jun 2009, 13:56
E-book readers owned: Used to have a PRS-500
Number of books owned: 600
Country: United States
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Re: My camera-on-glass-platen counterweighted G2

Post by daniel_reetz » 19 Jul 2009, 21:51

And BTW, thanks for taking the time to write this up. I've worried from time to time that once we all have working scanners, this place will more or less dry up...

spamsickle
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Joined: 06 Jun 2009, 23:57

Re: My camera-on-glass-platen counterweighted G2

Post by spamsickle » 19 Jul 2009, 22:35

daniel_reetz wrote:So, if I understand correctly, your platen + camera support is actually a framed, floating box that rests on the floor when not in use? Damn, that's cool.

Your camera clamp design is totally badass.
You understand correctly. While I can lift it with one hand, I'm also sitting on a little stool and stabilizing it with a knee on each of the two nearest legs of that floating box.

Just finished another book, and I'm back at the computer uploading it.

Thanks again for the impetus (and the switch). This was something I didn't even know I needed a couple of months ago, and going from not even realizing it was possible to having it working in such a short time is largely due to your original detailed write-up, plus the many ideas from the others who posted here (and on Instructables and bkrpr). While none of our designs are perfect (yet), they're more than good enough, and none of us had to shell out $5000+ for the commercial product.

you1
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Joined: 04 Mar 2014, 00:53

Re: My camera-on-glass-platen counterweighted G2

Post by you1 » 20 Jul 2009, 02:07

Wonderful contribution, thank you.

I'm sure the community (and myself) will consider your design elements...

Diversity of ideas should lead us to great discoveries :D

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