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

How much hingeallelogram is too much? Just enough?

Built a scanner? Started to build a scanner? Record your progress here. Doesn't need to be a whole scanner - triggers and other parts are fine. Commercial scanners are fine too.
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daniel_reetz
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How much hingeallelogram is too much? Just enough?

Post by daniel_reetz » 26 Aug 2009, 23:07

I'm hacking away at a design for a collapsible scanner and so far the "hingallelogram" design seems to be the most compatible, flexible, and most importantly, DOABLE idea.

My question: For those of you who use one (Edvin, Rob... others?) how much vertical travel have you needed in practice? How much vertical travel does your hingallelogram afford you? How well does it work? Any thoughts on the design going forward?

I feel stuck, and that sucks.

you1
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Re: How much hingeallelogram is too much? Just enough?

Post by you1 » 27 Aug 2009, 04:30

My hingeallelogram (HGL) allowed for two inches of vertical movement (see comment image: http://www.instructables.com/id/DIY-Hig ... offset=100)

I never tried the system without it. It allowed for several books that I scanned, and I think it worked well. I also think the two inches of vertical movement can accommodate for a large set of books. In theory, the two inch rise should accommodate for a book that is as much as four inches thick.

Why two inches, when the full range is closer to four inches? Well, if you notice from pictures I had put an "L" bracket to stop HGL from full range of motion. If I allowed a full range of motion, then HGL would not expand and then collapse to the other side. By keeping freezing the HGL to its max extension, it can only go back one way.

When I first was raising the platen, I notice that the HGL would not contract until raising past a certain angle (say 45 degrees), in which the HGL would collapse causing a sudden movement/fall of the raised platen. I added the spring to stimulate the contraction of HGL early to prevent the sudden movement.
I know several community members questioned its use/function; however, it worked for me...

As for function, it worked very well.

As for possible caveat:
As the HGL raises, your platen's depth changes. That is, on page 1 of the text book, the platen is the farthest distance from your chest (the collapsed HGL); and in middle of the book, the platen is closest distance to your chest (the expanded HGL). This depth movement is about 2 inches (the same distance as raised); which is not really a concern.

Also,
I don't know in regards to other scanners, but I found my book sliding up (away from me); which is why I needed a way to secure the book in one place (I used twine to strap the book).

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daniel_reetz
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Re: How much hingeallelogram is too much? Just enough?

Post by daniel_reetz » 27 Aug 2009, 08:18

Thanks for all that. I was thinking about making a much larger HGL, but I can see now that it is unnecessary. To illustrate your post, and to liberate the images from the increa$ingly-difficult instructables interface, I'm putting your images up here.

I've never had a problem with the book sliding using either of the scanners I built. When I throw together my HGL I'll let you know if it starts happening.
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you1
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Re: How much hingeallelogram is too much? Just enough?

Post by you1 » 27 Aug 2009, 13:52

I've never had a problem with the book sliding using either of the scanners I built
Then I'm sure the type of fabric back lining (velvet) that I'm using has a lot to do with it.
Even with my current system (http://www.diybookscanner.org/forum/vie ... p?f=1&t=74), I in inadvertently end up pushing the book away when I turn the pages.

Specifically, what lining do you use?

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Re: How much hingeallelogram is too much? Just enough?

Post by daniel_reetz » 27 Aug 2009, 14:33

It's a black neoprene foam, about 1/8" thick. I bought it from Harbor Freight Tools. It's sold there as toolbox drawer liner, to keep the tools from slipping. There's a kitchen/home equivalent, which I think is just called non-slip drawer liner.

HFT doesn't have the actual product on their website that I can find. They have a variation on it which is sort of bumpy. The stuff I used is totally flat. This is the variation:
http://www.harborfreight.com/cpi/ctaf/d ... mber=67055

you1
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Re: How much hingeallelogram is too much? Just enough?

Post by you1 » 27 Aug 2009, 16:28

tnx for the info

spamsickle
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Re: How much hingeallelogram is too much? Just enough?

Post by spamsickle » 27 Aug 2009, 19:30

I get so many complimentary mouse pads that I don't use, I just pulled the backing off of one and cut it in half. The strips grip just fine.

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Re: How much hingeallelogram is too much? Just enough?

Post by you1 » 27 Aug 2009, 20:34

spamsickle,

How large is your mouse pad to cover the whole cradle?
Or are you suggesting that only a small peace of "grip" is needed under the book; and the rest of the background is just black paint.

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