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

Austin Hackerspace kit build

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.
vitorio
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Austin Hackerspace kit build

Post by vitorio » 05 Jul 2013, 02:01

Today, I spent the entire day building the Hackerspace kit using the new manual as my sole source of instruction. I just posted feedback on the manual in that thread, but here I'm going to detail issues with the kit and the build itself.

My kit arrived a few months ago, with the box rather damaged. It sat in my foyer until this morning (July 4), when I took to my local hackerspace to spend the day building it.

To host it at the Austin Hackerspace, I became a voting member of the co-op, and offered to host it there indefinitely (I maintain ownership, but the hackerspace and general public will have free use of it). The vote was pretty much without incident, although there was some concern about copyright liability, discussion of which was tabled and hasn't yet resurfaced.

I had not inspected the contents of the kit after it arrived, so the first thing we did was take inventory, comparing it to the assembly manual. Everything seemed to be present, except for the two pipe end caps, and the 8" threaded rods had a bunch of stuff attached to them, which wasn't as illustrated.

Suggestion: It'd be nice if the manual had "prerequisites" as one of the first pages. Like, if you don't know what countersinking means, or pilot holes are, etc., this kit is not for you, find adult supervision.

I had picked up two pieces of generic 11x14 3/32" framing glass. This seems a little thin, and one of the hackerspace members later suggested I should have gotten tempered glass.

The hackerspace had a gallon of matte black enamel "primer + paint in one" that I decided to use, and we started by painting everything black.

Suggestion: It would be nice if there was a guide to glare and reflection issues with the kit, including which pieces really need to be painted black. It's nice that it looks nice with everything black, but it's also nice to get it assembled faster.

While the kit was drying, we went to Home Depot to look for the pipe end caps, and a countersink bit. We had zero luck on both. We ended up with a couple of alternative options (neither of which ended up being necessary): a toilet kit of some sort which included vinyl bits which had the appropriate threading, which we could have filed down to fit in side the pipe; and pipe end caps that fit outside the pipe, which we imagined we could drill a hole in to fit the threaded rod.

We also bought a 12.something mm countersink bit and hoped for the best.

Suggestion: Assembly went fine until we got to the handles. The manual didn't explain why you might choose one handle over another, and I wasn't about to go searching through the forums with bearing grease and black paint on my hands. We picked the large handle.

Then we got to the pipe handle bit, and realized we didn't need the end caps at all, because there seemed to be enough hex nuts to use the hex nuts-and-washers assembly method, so we did that. (Kit problem: there weren't enough hex nuts, so we were either missing more hex nuts, or missing pipe end caps.)

Also around this time, we realized the paint wasn't really fully dry and pieces were having paper bits stick to them and leaving residue, or parts were sticking to each other, or drips were making it hard to get pieces to fit together, etc. Another reason why only painting what is absolutely necessary is a good idea (or being more patient, but I don't have a lot of free time).

Kit problem: In addition to the pipe end caps being missing, as we assembled the cradle, we realized we had four identical cradle pieces, instead of two left and two right. We found an appropriate piece of replacement wood, and then cut two new pieces on a bandsaw, and finished the tabs with a handsaw. If I had not been at a hackerspace, and if I had not had help, I would have had to stop at step 21, until Dan could have shipped me replacement pieces.

Documentation/kit problem: I have no idea what the point of the threaded rod in the underside of the cradle is, nor why the cradle needs "left" and "right" pieces at all.

Documentation/kit problem: We also seemed to be short some of the 1" screws, and my kit's large and small braces had tabs that were thinner than the rest of the piece, giving them a "front" and a "back" which didn't seem to matter, but which also weren't illustrated in the assembly manual.

That's about it. We started at noon, and finished with a fully-assembled (but not fully-functioning) book scanner at 10pm. That included at least an hour going to Home Depot and back, and at least an hour replacing the two cradle bits. Here's what it looks like:
WP_001175 copy.jpg
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With the cameras in place, there was just enough juice in the included batteries to take a couple of test shots (I haven't purchased AC adapters yet, nor set up triggers or CHDK). These shots revealed a lot of glare and reflections, more than I expected. Are these known issues? Are there known solutions?

Here's the right side camera (left facing page):
atxhsscannerglare.jpg
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Note the HUGE glare top center. This isn't a huge book, but the light is right there. Also, what's with the yellow reflection from somewhere in the upper left?

Here's the left side camera (right facing page):
atxhsscannerglare2.jpg
atxhsscannerglare2.jpg (160.81 KiB) Viewed 6478 times
The light isn't visible here (why not? Aren't they symmetrical?), but there's more weird yellow reflection in the lower right (and really the whole lower half).

Also, why is my cradle visibly crooked???

I'll be working on these glare issues, maybe replacing the glass with something thicker (and tempered? polarized?), and working on making an electronic camera trigger of some sort, as well as producing a usage manual for the other hackerspace members and the general public.

Questions? Comments? Answers? :)

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Re: Austin Hackerspace kit build

Post by dpc » 05 Jul 2013, 13:02

Thanks for taking the time to post your build experiences. It was an interesting read.

Weird reflections - Those look like overhead fluorescent lighting fixtures in the room. Either drape something over the top of the scanner to block this or turn the room lights off to see If they go away.

Glare - It is odd that you'd see the glare hot spot on one side of the cradle and not the other, but this might be because of the content (white vs. black page) or the crooked cradle problem.
Some things to check:
Is the cradle centered under the light?
Are you getting inter-reflections from external light sources?
Replace the book with a solid black piece of paper on both sides of the cradle. This will make it easier to determine the source of the glare.

Crooked cradle - Check your camera mount. I suspect it's the camera shooting that side that's out of alignment rather than the cradle. You can shim the camera to compensate if that's the case. Otherwise, make measurements from the front/rear cross members near the base to the cradle or cradle carriage to see if there's a difference.

Glass - Go to a glass shop and get double-strength (1/8") clear plate glass (tempered typically has a tint). If you're not comfortable working with sharp glass edges during assembly, ask them to seam the edges ($).

Black parts - If you replaced the platen glass with a mirror and take a shot with the camera, anything seen in the resulting image needs to be painted black.

Countersink bit - Sears or even your local auto parts store will likely have this. There's also places like Harbor Freight Tools that will have it (there's a HF in Austin).

Disclaimer: I've never seen or built a scanner from one of these kits, but I've designed scanners from the ground up and have had to deal with some of the problems you've encountered.

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Re: Austin Hackerspace kit build

Post by daniel_reetz » 05 Jul 2013, 16:53

To begin responding, I want to say thanks, Vitorio, for having patience and for taking the time to write this up. Means a lot to me and I will be incorporating what I can from your feedback.

There have been some small updates to the manual recently (link to assembly manual), I just uploaded them. The manual you are referring to is this one. There have also been a number of small changes to the kit, including different hardware counts.
vitorio wrote:8" threaded rods had a bunch of stuff attached to them, which wasn't as illustrated.
We started putting the wing nuts, washers, and nuts on the threaded rods because it helped with accounting. Should we stop doing this? Re-drawing them partially assembled is more work than not putting them together at all.
threaded_rods.jpg
threaded_rods.jpg (71.52 KiB) Viewed 6435 times
vitorio wrote:Suggestion: It'd be nice if the manual had "prerequisites" as one of the first pages. Like, if you don't know what countersinking means, or pilot holes are, etc., this kit is not for you, find adult supervision.
Would this be better as a part of the store page? Or the wiki? I'd hate to ship a kit to someone, only for them to feel inadequate. In any case, this is probably a great idea.
vitorio wrote:Suggestion: It would be nice if there was a guide to glare and reflection issues with the kit, including which pieces really need to be painted black. It's nice that it looks nice with everything black, but it's also nice to get it assembled faster.
I think I am always going to suggest that people paint all parts black, but a guide to fixing reflection issues (including shielding the scanner from overhead light) is definitely a good idea.
vitorio wrote:Suggestion: Assembly went fine until we got to the handles. The manual didn't explain why you might choose one handle over another, and I wasn't about to go searching through the forums with bearing grease and black paint on my hands. We picked the large handle.
I think you mean choosing between these two parts (circled in red). There is really nothing other than personal preference here. I have considered including only one with the scanner. Do you think this is a good idea? It would save time, effort, and wood.
handles.jpg
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vitorio wrote:Kit problem: In addition to the pipe end caps being missing, as we assembled the cradle, we realized we had four identical cradle pieces, instead of two left and two right. We found an appropriate piece of replacement wood, and then cut two new pieces on a bandsaw, and finished the tabs with a handsaw. If I had not been at a hackerspace, and if I had not had help, I would have had to stop at step 21, until Dan could have shipped me replacement pieces.
I would still like to send you some replacements, probably a full set of four. Interested?

vitorio wrote:Documentation/kit problem: I have no idea what the point of the threaded rod in the underside of the cradle is, nor why the cradle needs "left" and "right" pieces at all.
The threaded rod clamps the "cradle wings" down securely to the cradle platform by pulling the right cradle support and left cradle support together in the cradle platform piece.. Without the threaded rod, the sides of the cradle can just fall off. This may be why your cradle appears crooked. Also, your cradle is designed to be adjustable for each book, so you need to be able to loosen them to open the cradle up for a wider spine.

I need to think for a minute as to whether or not it's possible to eliminate the left-and-right-handedness. I think it is only possible to move the handed-ness into the cradle wings, but I'm not sure.

vitorio wrote:Documentation/kit problem: We also seemed to be short some of the 1" screws, and my kit's large and small braces had tabs that were thinner than the rest of the piece, giving them a "front" and a "back" which didn't seem to matter, but which also weren't illustrated in the assembly manual.
I think some of your screws may have been lost in shipping damage, but missing screws have happened a few times. You should have had 4 of them, and then a bunch of 3/4" screws to hold the glass braces in place. You're correct that the front and back brace orientation doesn't matter. I do see that the manual pictures them at full thickness, this is definitely a change that needs to be made.

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Re: Austin Hackerspace kit build

Post by vitorio » 05 Jul 2013, 22:16

dpc wrote:Countersink bit - Sears or even your local auto parts store will likely have this. There's also places like Harbor Freight Tools that will have it (there's a HF in Austin).
Yeah, HFT didn't have one either, which is why I called it out, in case it was an unusual size.
dpc wrote:Disclaimer: I've never seen or built a scanner from one of these kits, but I've designed scanners from the ground up and have had to deal with some of the problems you've encountered.
I encountered a lot of similar issues with an all-acrylic kit I built and tested, so I'm familiar with the general solutions; I was more interested in known best practices for the hackerspace kit.

That said, this is a fantastic checklist that should go in a FAQ somewhere, for basic image quality troubleshooting tips.

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Re: Austin Hackerspace kit build

Post by vitorio » 05 Jul 2013, 22:24

daniel_reetz wrote:To begin responding, I want to say thanks, Vitorio, for having patience and for taking the time to write this up. Means a lot to me and I will be incorporating what I can from your feedback.
You're welcome, and thanks for helping me get this far.
daniel_reetz wrote:We started putting the wing nuts, washers, and nuts on the threaded rods because it helped with accounting. Should we stop doing this? Re-drawing them partially assembled is more work than not putting them together at all.
No, just noting that the totals include parts pre-screwed onto other parts or something, would be enough. Just call it out that it's happening.
daniel_reetz wrote:
vitorio wrote:Suggestion: It'd be nice if the manual had "prerequisites" as one of the first pages. Like, if you don't know what countersinking means, or pilot holes are, etc., this kit is not for you, find adult supervision.
Would this be better as a part of the store page? Or the wiki? I'd hate to ship a kit to someone, only for them to feel inadequate. In any case, this is probably a great idea.
Yeah, it should probably be found earlier. Store page would be good. And everything should be in the wiki eventually. :)
daniel_reetz wrote:I think I am always going to suggest that people paint all parts black, but a guide to fixing reflection issues (including shielding the scanner from overhead light) is definitely a good idea.
I'll document this as much as I can when I go back to the space next, much like I did with my acrylic setup.
daniel_reetz wrote:I think you mean choosing between these two parts (circled in red). There is really nothing other than personal preference here. I have considered including only one with the scanner. Do you think this is a good idea? It would save time, effort, and wood.
handles.jpg
If there's no practical difference, then, yeah, pick one for us.
daniel_reetz wrote:
vitorio wrote:we realized we had four identical cradle pieces, instead of two left and two right
I would still like to send you some replacements, probably a full set of four. Interested?
Maybe later, after I confirm the cradle isn't really crooked!

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Re: Austin Hackerspace kit build

Post by pleonard » 11 Jul 2013, 01:41

Just a quick note on the 'crooked cradle' problem -- in addition to making sure your cameras are mounted straight, double-check that the vertical parts of the cradle supports are all the way into the grooves. The sloped front of the tongue can fool you into putting them too far forward (to form a smaller cradle) than the parts actually support. If this is happening on the top/bottom of one cradle side, they make the book appear slightly skewed when photographed.

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Re: Austin Hackerspace kit build

Post by vitorio » 17 Aug 2013, 22:44

Blergh.

I went into the Hackerspace to set up triggering with CHDK, and hopefully do some test scans.

Triggering
I went with two generic 5V USB AC adapters plugged into a power strip. Turn on USB Remote in CHDK, toggle the power strip on and off, and both cameras fire. Great!

Unfortunately, power-based USB remotes in CHDK mean you can't download images over USB. Since I want this to be fairly easy to use (and risk less breakage), I don't want anyone to have to touch the cameras. This isn't possible now (although I got the CHDK people thinking about a setting to let USB remotes only be active in "record" mode, so you could just switch between playback and record to allow for downloading).

To have the cameras permanently mounted, they need AC power, and a PTP (software) USB trigger, which means a host computer. I haven't looked into this at all yet.

AC Power
Because I don't want people messing with the cameras, I want them on AC power. The AC adapter for these A2200s is a right-angle adapter, which is too wide for the slot for the tripod mount screw thing. I started drilling out the end of one of the slots, but now I can't center the camera with the AC adapter plugged in, because it's off-center compared to the tripod mount.

I'm not sure what to do about that. I really don't want anyone to have to touch the cameras, not the least reason of which is that removing the SD card risks breaking CHDK. I essentially need a no-angle DC extension cord that's no wider than the tripod mount screw width.

I'm currently charging the camera batteries so I can get the cradle fixed up and do some test scans on battery power.

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Re: Austin Hackerspace kit build

Post by vitorio » 18 Aug 2013, 04:51

How to use the Austin Hackerspace book scanner

First, some caveats:
  • The book scanner is calibrated for the exact location it is currently sitting in. If it needs to be moved, I will have to come in and recalibrate it. It should not be moved arbitrarily or without notice.
  • The book scanner is a little fragile. The glass currently mounted in it seems to shift a little over time, and the cradle under it is not tightened down when not in use, and the cameras are attached only by a few turns of a tripod mounting screw, etc. Please be careful with it, and around it.
  • The book scanner can only scan books with pages of 8.5"x11" or smaller. Larger books will have an unusable amount of glare. Sorry.
  • Paperbacks will take longer to scan than hardcovers.
  • You will have to bring in a computer to download the photos from the cameras over USB. You must not take the SD cards out of the cameras to download your photos.
  • Under no circumstances should you take the SD cards out of the cameras.
  • Do not remove the SD cards from the cameras.
  • These instructions are a little complicated right now, but they will get simpler over time, as we improve the scanner configuration.
  • If you are uncomfortable with any of these instructions, email me and we'll set up a time for me to come in and help you scan your stuff.
How the scanner works
The book scanner has two digital cameras pointing down at a V-shaped glass platen. The book sits in the cradle underneath the platen. The cameras have electric triggers and special software.

With your right hand, you pull the handle down, which raises the book up, and flattens the pages against the glass. With your left hand, you trigger the electric trigger, which makes the cameras take pictures of the pages. You raise the handle back up (with your right), turn the page (with your left), and repeat the process until you've photographed every page of the book.

Then, you plug each camera into your computer over USB (do not take the SD card out), download the photos, and erase the photos from the camera so the next person can scan their books.

How to actually do that
1. Check the batteries and USB
In front of the scanner is a power strip, with two USB power adapters and two camera battery chargers. If there aren't camera batteries in the chargers with the lights reading "Full," then the last person to use the scanner was a jerk and you probably won't be able to scan anything until the batteries are charged. Sorry.

If there are batteries in the chargers, and both chargers say "Full," then turn the power strip off. The red lights on the USB power adapters should go out.

Check to make sure the USB plugs are in place. The USB power adapter marked "Left" should have a beige USB extension cord plugged into it, also labeled "Left." The extension cord should have a white USB cable plugged into it, also marked "Left," going into the digital camera on the left side of the scanner (your left, as you face it). Then, the USB power adapter marked "Right" should have a beige USB extension cord plugged into it, also labeled "Right." The extension cord should have a white USB cable plugged into it, also marked "Right," going into the digital camera on the right side of the scanner (your right, as you face it).

2. Set up the left camera
Starting with the left camera, gently unscrew it from the tripod mount. Don't take the tripod mount out. (If you do, there's also two washers: one between the bottom of the mount and the wood, and one between the top of the wood and the camera. Make sure you don't lose anything.) Pop open the bottom of the camera and insert a battery. There should also already be an SD card in there. Don't take it out. If you take it out, don't unlock it. If you unlock it, lock it and put it back in. Seriously, leave the SD card alone. (If there isn't an SD card in the camera, someone's in a lot of trouble, but it also means you can't scan anything. Sorry.)

Gently screw the camera back onto the tripod mount. On top of the wood bar the camera is screwing into, on the left side of the camera, is a piece of tape. Line the camera up against the right side of the tape so that if the camera had a perfectly square left edge, it would just touch the right side of the piece of tape. Since the camera has a rounded corner, squint and estimate. Then, take the level and place it against the back of the camera, and make sure the camera is level.

Turn the camera on by holding down the on-off button on top for like half a second or something. If you don't hold it down long enough, it'll start up in "Playback" mode and say "No Image." (If it starts up in Playback mode and you see a picture, someone was a jerk and didn't erase the camera when they were done. Sorry.) If it starts up in Playback mode, tap the shutter button quickly to switch to Record mode. Make sure the electric triggers are turned on by tapping the blue Play button briefly (don't hold it down). You should see "Default Script" and "<ALT>" at the bottom of the screen. Tap the "MENU" button and you should see "User Menu", "Main Menu" and "Enable Remote". "Enable Remote" should have a dot next to it. If it doesn't, hit the down arrow twice to highlight it, and tap "Func./Set" to enable it. Exit the menu by tapping "MENU" and then the blue Play button briefly again. Finally, zoom in three times. You should be able to just make out the bottom of the "V" shaped platen at the bottom of the screen.

3. Set up the right camera
Gently unscrew the right camera from the tripod mount. Don't take the tripod mount out. (If you do, there's also two washers: one between the bottom of the mount and the wood, and one between the top of the wood and the camera. Make sure you don't lose anything.) Pop open the bottom of the camera and insert a battery. There should also already be an SD card in there. Don't take it out. If you take it out, don't unlock it. If you unlock it, lock it and put it back in. Seriously, leave the SD card alone. (If there isn't an SD card in the camera, someone's in a lot of trouble, but it also means you can't scan anything. Sorry.)

Gently screw the camera back onto the tripod mount. On top of the wood bar the camera is screwing into, on the left side of the camera, is a piece of tape. Line the camera up against the right side of the tape so that if the camera had a perfectly square left edge, it would just touch the right side of the piece of tape. Since the camera has a rounded corner, squint and estimate. Then, take the level and place it against the back of the camera, and make sure the camera is level.

Turn the camera on by holding down the on-off button on top for like half a second or something. If you don't hold it down long enough, it'll start up in "Playback" mode and say "No Image." (If it starts up in Playback mode and you see a picture, someone was a jerk and didn't erase the camera when they were done. Sorry.) If it starts up in Playback mode, tap the shutter button quickly to switch to Record mode. Make sure the electric triggers are turned on by tapping the blue Play button briefly (don't hold it down). You should see "Default Script" and "<ALT>" at the bottom of the screen. Tap the "MENU" button and you should see "User Menu", "Main Menu" and "Enable Remote". "Enable Remote" should have a dot next to it. If it doesn't, hit the down arrow twice to highlight it, and tap "Func./Set" to enable it. Exit the menu by tapping "MENU" and then the blue Play button briefly again. Finally, zoom in three times. You should be able to just make out the bottom of the "V" shaped platen at the bottom of the screen.

4. Set up the lamp and platen
Find the short, dangling, three-prong power plug for the scanner's lamp, and plug it into the extension cord that should be right there. (Do not plug it into the power strip.) The lamp should come on. (If the lamp does not come on, you won't be able to scan. Sorry.)

Turn the overhead lights off (the switch on the wall behind whatever that machine is). If someone else is also working in that area and needs the lights on, you won't be able to scan. Sorry.

Run your finger along the bottom of the "V"-shaped platen glass. The two pieces should meet evenly. If one piece has fallen a little, gently push it back up. They're just held in with screws and foam, so don't risk breaking them: unscrew the droopy side (on both sides of the scanner, push it back in place, and then screw it back in. (If you crack the glass, everyone will be very upset with you, and you won't be able to scan. Sorry.)

With the scanner lamp on, you will be able to see all of the fingerprints, smudges and smears on the glass. Dust the glass off with a duster, then use glass cleaner and paper towels to clean both sides of each pane of glass. If the glass is not perfectly clean, you will be able to see it in every photograph, and smears and smudges will cause extra glare on your pages, making them illegible.

5. Set up the cradle and blackout cloths
Pull the handle up to lower the cradle down. Open your book up to the middle and place it on the cradle, nearer to the back. Pull the handle down to press the pages against the glass. With the handle down and the pages against the glass, check one of the camera viewfinders to make sure the book is centered horizontally on the screen. If it's not, pull the handle up, adjust the book, pull it down, and check again.

If the book doesn't sit well in the cradle, pull the handle up, and you can actually take the whole cradle out. That thing that rolls back and forth just lifts right out of there. The left and right sides of the cradle are detachable wings. Adjust them so the space between them is a hair larger than the spine of your book, then tighten the wingnuts a little to keep it from moving around. Put it back in place and center your book again.

There are two blackout drop cloths taped into place on the front and back of the scanner already, but there is also a long one bundled up on top of the lamp. Drape it over the top of the scanner, evenly, so it covers the top, left and right sides.

6. Take pictures of pages
Finally.

With your right hand, pull the handle down to lift the cradle up and press the pages against the glass. The "V"-shaped platen should dig right into the spine of the book.

With your left hand, turn the power strip on. You will hear both cameras chirp as they focus. Still with your left hand, turn the power strip off. You will hear both cameras take a picture.

With your right hand, pull the handle up to lower the cradle down. With your left hand, reach in and turn the page.

Repeat.

7. Download your pictures
Unplug the scanner lamp. You can also turn the overhead lights back on. Lift up the long blackout cloth so you can get to the cameras.

On your computer, make a folder or directory with the title of your book. Make two folders inside that directory, one named "Left" and one named "Right."

Starting with the left camera, turn the electric trigger off by tapping the blue Play button briefly (don't hold it down). You should see "Default Script" and "<ALT>" at the bottom of the screen. Tap the "MENU" button and you should see "User Menu", "Main Menu" and "Enable Remote". Hit the down arrow twice to highlight "Enable Remote," and tap "Func./Set" to disable it. Exit the menu by tapping "MENU" and then the blue Play button briefly again.

Unplug the beige USB extension cord marked "Left" from the USB power adapter and plug it into your computer. Download the photos from the camera (however that works on your computer) into the "Left" folder you just made. Then, delete the photos from the camera. (Do not "format" the camera.) Unplug the camera from your computer and plug it back into the USB power adapter.

Then, on the right camera, turn the electric trigger off by tapping the blue Play button briefly (don't hold it down). You should see "Default Script" and "<ALT>" at the bottom of the screen. Tap the "MENU" button and you should see "User Menu", "Main Menu" and "Enable Remote". Hit the down arrow twice to highlight "Enable Remote," and tap "Func./Set" to disable it. Exit the menu by tapping "MENU" and then the blue Play button briefly again.

Unplug the beige USB extension cord marked "Right" from the USB power adapter and plug it into your computer. Download the photos from the camera (however that works on your computer) into the "Right" folder you just made. Then, delete the photos from the camera. (Do not "format" the camera.) Unplug the camera from your computer and plug it back into the USB power adapter.

Instructions on how to turn your stack of "left" and "right" pages into an ebook, PDF, or whatever, are left as an exercise for the reader.

8. Charge the batteries
If you're going to scan another book, you can start over from step 2. You can probably do at least two books before the batteries die. Pay attention to battery levels. If they die mid-scan, you really must charge the batteries, and then download the photos over USB (don't you dare take the SD card out of the cameras), and erase them for the next person. Do not leave scanned pages on the cameras.

When you're done scanning, set the camera batteries up to charge so the scanner will be ready for the next person.

Starting with the left camera, gently unscrew it from the tripod mount. Don't take the tripod mount out. (If you do, there's also two washers: one between the bottom of the mount and the wood, and one between the top of the wood and the camera. Make sure you don't lose anything.) Pop open the bottom of the camera and remove the battery. Don't take the SD card out. Put the battery in one of the chargers, and gently screw the camera back onto the tripod mount. (It doesn't have to be lined up or level, just screwed in.)

Now, the right camera. Gently unscrew it from the tripod mount. Don't take the tripod mount out. (If you do, there's also two washers: one between the bottom of the mount and the wood, and one between the top of the wood and the camera. Make sure you don't lose anything.) Pop open the bottom of the camera and remove the battery. Don't take the SD card out. Put the battery in the other charger, and gently screw the camera back onto the tripod mount. (It doesn't have to be lined up or level, just screwed in.)

That's it.

Technical notes and future work
  • The cameras are Canon PowerShot A2200 digital cameras, taking 12-14MP JPEG photos, "Fine" quality.
  • The cameras are running CHDK 1.20.3034 (stable), configured to provide the electric trigger on the User Menu, booting from the 8GB SD card.
  • The cameras are set in Program mode, ISO 80, white balanced against a sheet of white paper pressed against the glass platen with the scanner lamp on and overhead lights off and blackout cloths in place, center brightness, no flash.
  • You'll get approximately 350dpi photos from the scanner.
  • The cradle seems to be slightly crooked, the right side closest to you seems to bow to the right a bit. Sorry.
  • The electric triggers need to be replaced with a software-based triggering system, which will require a computer of some sort triggering the photos as well as being the intermediary for downloads.
  • The batteries need to be replaced with custom AC adapters. The existing AC adapters (in the boxes in the ziploc back next to the scanner) are right-angle and too thick to plug into the camera. A very slim cable needs to be plugged into the fake batteries, with only a millimeter or two of height beyond the battery bottom, and only a slim cable beyond that, or the cameras won't be able to be mounted properly.
  • The paper residue from the paint not being dry all over the scanner needs to be cleaned up.
  • A duster, glass cleaner, and towels need to be by the scanner at all times.
  • A drop cloth needs to cover the entire scanner when not in use to keep it clean.

vitorio
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Re: Austin Hackerspace kit build

Post by vitorio » 18 Aug 2013, 05:09

So that's basically your usage manual there. I'll be writing a software processing manual, as well as figuring out some sort of inexpensive computer solution, at some point, because this whole thing is not foolproof without AC and PTP-based CHDK triggers, and then I don't even know what to do about turning it upside down for paperback mode yet.

On glare and painting things black
You know the platen assembly? Front plate, back plate, and everything in between and up? You know where that sits on the cradle assembly? That spot? Okay, so, if the lights are off, it seems like the only parts of the scanner that need to be painted black and covered to protect from glare, is everything from that spot on up. Nothing else matters.

If the lights are on, you really should be inside a blackout tent.

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daniel_reetz
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Re: Austin Hackerspace kit build

Post by daniel_reetz » 18 Aug 2013, 14:51

Thank you again, Vitorio. FYI, I have been working on fixing the user manual and incorporating some/many of your suggestions (and also Matti's suggestions). There will be a new version within a week or so. Dario is working on it.

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