My 3rd Generation Scanner Build Thread

[daniel_reetz]

I'm almost ready to build my final scanner. I have a deadline of August 15th and a pile of parts.

IF all goes well, it will have these features:

*A glass platen with drawer slides similar to other designs on this forum, but thinner and with the glass directly abutted, perhaps painted black on the cut edge.
*Cameras running You1's excellent "smart button" software.
*One power supply running everything (no more changing batteries!).
*A compact display system to visualize the camera output.
*A drawer slide cradle.
*LED lighting -- this LED lighting will normally remain at a low intensity, but fire a mighty blast during exposure.
*All critical parts will fit inside my laser cutter so I can reproduce them easily.

[tsttm]

Ah.. i haven't got around to piecing together my scanner, but i've bought my cameras now..so i'm committed.

Thanks for posting this. I see there's been a number of changes over the original build & your list helps me sift through some of the improvements/changes that i might want to include.

What was the reason for switching to glass vs acrylic again? was it durability..or reduced reflection?? well, i already picked up my plastic pieces so i'll probably stick to using them.

Also, can you elaborate a little on how you plan to power everything by powerbar (are the cams gonna be powered through usb?). what about the switch, are you still using batteries to trigger that?

thanks!

[daniel_reetz]

The reason I want to try glass is primarily that I think the structural rigidity of glass will allow for a folding platen. Otherwise, I think acrylic is still the best way, especially for my original design.

As far as power, I plan to build or scavenge a single high-amperage power supply. I'll run regulated power to the cameras from it... I don't have my A590s in front of me, but if they don't have a DC jack, I'll just make a fake battery pack to install. The rest of the rig should run easily on 5v, including the hub. However, this is going to be a hella complicated wiring job, so I wouldn't base your scanner on it if you can get things going with some batteries.

[you1]

Looking forward to seeing your 3rd generation...

[daniel_reetz]

Well, it employs some of the design principles you warned against, so we'll see how well it goes. I'm perfectly fine with this revision being total trash, because I've learned a lot in the process of designing it. I've also been comfortable with tossing out my first design entirely, just because I feel there are still a lot of possibilities to explore. The only thing is, I'm going to need a working book scanner real soon... so...

The first thing I did was cut out an 11x23" cardboard base to start prototyping with. I chose this size because it will fit in the laser cutter.

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Then I started mocking up a folding "cradle holder" (book holder holder, in book scanner 1 lingo). So far, so good.

USPS is a good source of cardboard for prototyping.

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The metal block is a "123 block" named because its sides are 1,2, and 3 inches. Very useful for layout/squaring things.

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Hot glue to the rescue! Industrial hot glue!

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Done enough for to play around with it.

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Time to mount it up.

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Motion test, seems straight enough for fooling around.

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[daniel_reetz]

I played around with a few ideas for the cradle. The big idea is to have the cradle and platen fold somehow. I think I've stumbled upon a solution that doesn't need the two sides of the cradle to be connected in any way, but that will be documented in a future post.

Checking the fit of two cradle halves.

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Looks OK. A bit top-heavy.

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Brainstorming.

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Seeing how, if at all, the design would benefit from a rotating platen. Verdict: no benefit.

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However, placing the cradle halves on the little cradle holder thing gave me some ideas.

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[daniel_reetz]

After a few beers and a lot of lasering, I start to get some interesting ideas. I don't know if these images really need explanation, but here goes anyway.

I keep a notepad and camera with me pretty much wherever I go. I never keep the notepads, just the pictures. Here I'm thinking about how to make a glass platen fold up.

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While thinking about glass platen stuff, I found a pile of quick release lock-things from a tape backup machine I took apart. hmmmmmm....

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I realized that the base could fold so I marked it and returned to thinking about quick release stuff... This is the beauty of having a laser and a huge pile of sharpies.

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Test fit... might work.

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Drawing for posterity. This is where I realized that I'd have racking issues like Edvin was talking about in the portable book scanner thread.

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Not worth much, but here it is anyway.

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This is more or less the idea I'm working on now...

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[daniel_reetz]

I found some piano hinge at a local hardware store and started work mocking things up. I want to get these uploaded, but I'm quickly running out of time to notate them. I'll get to that another day.

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[daniel_reetz]

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[daniel_reetz]

I started working on a mock-up of my platen yesterday. So far, it is a big disappointment as cautioned b y Edvin. However, I think that it might be able to be remedied with some clever design, so I'm not giving up yet. This is only the beginning, and besides, it's made of 1/8 fiberboard. Not exactly the most rigid material.

The primary issue is that it is racking -- that is, when I lift the platen, the whole thing twists instead of raises. The secondary issue is weight, the platen is heavy and won't be fun to use. The reason I'm doing things the way I am is to make this thing portable, which is very important to me, so solutions that reduce portability are less desirable.

I will continue working on this design for a bit. I still have some time. Any ideas would be very welcome. So far, my only possible solution to the racking issue would be more drawer slides (one at each corner)... but on further reflection, that probably won't work.

I'll comment on each picture later.

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