Brainstorming about portable book scanners.

[daniel_reetz]

Rob and I started discussing portable book scanners back in April. There are some difficulties with producing a portable model, but none of them are impossible to overcome. The ideal format would be something that could fit in a briefcase or backpack. Even better if it does not require AC power.

Some ideas we've had (and please, feel free to expand on these):

A collapsing platen that folds like origami:

Brainstorming about a foldable platen... say the platen is all 1/4" acrylic (as mine will be, once the damn stuff comes in the mail -- apparently Weld-On acrylic glue has to ship ground, because the vapors make airplanes dizzy). Instead of welding the acrylic together, suppose you stack the two pieces of acrylic, one on top of the other (i.e. you take your 2 pieces of 11" x 15" x 1/4" and stack them to make 11" x 15" x 1/2"). I'd draw a diagram, but at ASCII art I am teh sux0rz.

Now, along one edge, glue a long strip of flexible yet strong material, forming a long hinge. Maybe a strip of cloth from an old pair of jeans, or some kind of rubber or plastic. Something that won't fall apart after being folded and unfolded hundreds of times, and something that won't let one plate move much with respect to the other plate.

I think the only reason I like 1/4" because it's big enough not to require precision work. I suppose the thing could be made of 1/8" with a 1/4" wide strip hinge.

Next, something is needed to hold the plates rigidly at 90 degrees when unfolded. What if we split the 6" x 6" diamond pieces down the middle, and added strip hinges everywhere. Then, it could fold flat, and when unfolded, maybe a bar across the hinge could prevent the diamonds from folding back up.

Or maybe use more bolts and wingnuts to hold the whole contraption rigid somehow.

I see what you're saying. I've had similar thoughts, but it seems to ... hinge... on the hinge.

My first thought was simply to use a flat piece of metal in place of the current gussets. Ignoring thickness for a moment, imagine screws portruding from the person-facing side of the platen (the cut faces of the acrylic along the 11" edges). You'd simply have a metal bracket (or two) that bolted onto that side, like a gusset that went on the facing edges of the acrylic.

The problem with that kind of approach is that the platen bends in the middle. Before I learned to glue acrylic, I made two platens that weren't glued along the bottom edge. They both bowed and it caused lots of problems. Your hinge might help -- and I love the collapsible nature of it -- but I suspect we'd need something rigid.

Another approach is to use glass. Glass is nice and rigid (and thin -- my 1/4" platen sometimes wouldn't let me see into the gutters of books, so I made the 1/8" one). One could make a simple, flat thing in the shape of a gusset with a slot for each pane of glass. It could be made of a slab of plastic or wood. Not as elegant as your folding idea, but more rigid and just as flat-packable. I've attached a real-world drawing to communicate my idea a bit better. "GST" is "gusset-shaped thing".

I have some other ideas for making the base vastly smaller as well as making the UST or VST flat-packable. If you used linear bearings like drawer slides it could get super-small and be a single piece of wood with an angle cut in it to support the bookholder/cradle.

Oka has some ideas as well, I think his idea of not using the frame is pretty interesting:

I think to make portable book scanner, we can use hinges on the botom of book holder, and put the lock so the book holder is always on 90degre if we open it.. the thinner miter box and small rails, knock down counter top material the PVC pipe may be can help.and we can put the miter box on the table and not using frame. the challenge is the portable book scanner must be put in the 20"X20"X5" cardbox, and for light we can use LED and battery.

[suryandaru]

Most simple Making portable book scanner for under 100 pages book is using single platen, but for up 100 pages is comfortable to use V platen. V platen scanner need more place than single one. soo making all material in knock down may be can help. and may be posible to put the lamp on otophile arm not straight over the v platen,and screw the arm near the hinge v platen. so the book scanner have 3 arm. and if the lamp using LED we can use dc power. but how to make LED light for this? I think is rather dificult to explain with words, and may be making it will be better.isn't it?

[jradi]

Here's an idea, you don't need the platen to be at 90 degrees. How about 120 degrees or 160 degrees? Just swap the location of the lights and cameras - cameras overhead and lights to the side?

Now that the platen is flatter, you also don't need for it to be foldable. You can take a single sheet of acrylic and bend it to 120 or 160 degrees with a heat gun. Make a wooden mold of the angle you want and gently heat the acrylic along the bending edge - that's how other book scanner projects are made.

Another thought, shrink the platen down. Most books are fairly small. The average trade paperback is 8.5 x 5.5 inches, the average hardback is about 6 x 10? You can make the platen as small as 12 inches wide by 10 inches tall - perfect for a backpack or small duffel.

[jradi]

Why do we want to make the book scanner portable? Is it just so we can store it easier? I like the idea of smaller. Once I started thinking about it, I realized the vast majority of books I own are trade paperbacks or your average hardback - I can easily shrink everything to accommodate these dimensions. Maybe for V2. One more weekend to go and I'll finally be done - everything is assembled except for the firmware.

[daniel_reetz]

My primary reason for wanting a portable scanner is so that I can head into the government documents section of my library (or any section, for that matter) and scan without removing books. I think Oka would like to take it from village to village, and I also have the idea that it would be great for mailing. I know several people with awesome rare book collections who won't mail them to me for scanning.

Flattening the platen, eh? Very interesting...

[Karyudo]

The more you flatten the platen (heh, heh), the more stress you put on the binding of the book. Especially if it's a paperback. Maybe a hardback not so much.

[spamsickle]

The pictures I posted over on the Instructables site show how the V-shaped cradle can be portable now, though it sacrifices the side-to-side slide. I wonder, for books with at least a half-inch inner margin, whether it wouldn't be possible to just lay a pair of sheets of 1/4-inch acrylic over the book and shoot. It wouldn't be as fast as having a platen that could be raised and lowered with one hand, but it might still work. The book is already somewhat shaped by the cradle, and 1/4-inch sheets may be heavy enough to flatten them the rest of the way into a reasonable plane.

I doubt there would be a problem with bowing if 1/4-inch acrylic was used without being attached along the centerline. That stuff's pretty stiff.

The big problem to me is the lights. While it may be possible to use two tripods to position the cameras, and another two tripods to position the lights, I've been in government buildings where they didn't want me plugging in my laptop, much less a pair of 100-watt (or 200-watt!) halogens. The libraries around here are more reasonable, with accessible plugs and a laptop-friendly attitude, so that may or may not be a problem in practice.

[daniel_reetz]

I don't think lights are that big a problem if you use high-output LEDs like Cree q5's. You'll need some heavy batteries, but that's not the end of the world. Some of these LEDs can put out around 200 lumens when properly driven. An array of 4 or 5 per side, from matching bins, should do the trick.

Spamsickle, you mean this comment? I see -- your scanner is essentially flat-packable.

[spamsickle]

Yes, my pictures are right above the comment that says "small footprint."

It may look unstable and unworkable, but honestly, when you set up the four boards, it stabilizes itself. Those two v-shaped boards are as warped as a rowboat (though the bottom edge is straight), but with the shelves in them it all becomes sturdy and stable. I wouldn't want to sit on it, but it holds a book just fine.

[rob]

Suryandaru has an interesting idea. We definitely don't want to open the book any more than 90 or 100 degrees, because that stresses the bindings on older books. However... why not just photograph all the right-hand pages of the book, flip the book, and then do all the left-hand pages? Certainly it would take twice as long, but it only requires one side of the platen, and therefore eliminates a great deal of material.

I have tried 1/4" acrylic for the V-platen, and I wasn't very happy with the 1/4" in the middle that it obscured. However, since we wouldn't have two 1/4" pieces butting up against each other, you could use 1/4" acrylic which would eliminate bowing.

Just be sure to sand a little bit of the edge off, so that there's no danger of damaging the page when you jam the platen into the book.

Of course, this would require engineering a new hinging system...

Instead of doing all the right-hand pages and then all the left-hand pages, you could also flip the platen onto the other side and then take the other side picture. You could use a two-button mouse as the controller, one button per camera.