Drake Ravensmith's build

[jerrytsai]

Thanks for an incredibly useful and thorough description of your build. You seem to have collected many innovations and thoughtful suggestions across the entire site.

I was wondering about the use of the keyboard slides for the platen slide on the column. In your discussion with clemd973 (http://www.diybookscanner.org/forum/vie ... 8&start=20), he mentioned that "the keyboard slides have a built in mechanism that apparently prevents you from pulling it too far and it must be 'forced' (with minimal force) all the way up after about 8-10 lifts".

I was wondering whether you experienced this phenomenon as well, or whether you solved it in your build (perhaps by placing the slides higher or lower).

[Drake Ravensmith]

I'm glad you're finding it useful!

As for the keyboard slides, I did when I first put the slides on. I touch on it briefly in the pdf. I'm not sure why but the slides were occasionally stopping an inch or so from the top. I found it mildly inconvenient and tried to ignore it. On the next raise it would often go all up way up. My best guess is that the L-shaped pieces were attached to the platen slider too tightly and the holes I drilled didn't allow for them to be able to shift outwards at all. I believe that put some tension on the slides as they were being raised and it occasionally hits that mechanism Clemd was talking about. In fact, the first time I raised it, the right side slide snapped completely snapped apart and I had to re-drill some of the platen slider holes. After I painted it, I moved the holes around a bit more and the problem usually only presents itself when I first get started. After that, I can get a few dozen raises done without it stopping at all. (Remember, I still haven't scanned all the way through a book yet.) I think so long as the L-shaped brackets are given some wiggle room, they'll raise just fine.

It's just occurred to me that the problem may be that the slides aren't attached perfectly level with the column. If one of the slides were going up at a slight angle, it would produce some tension. Either way, that tension can be greatly relieved by slightly loosening the screws that hold the brackets to the platen sliders. Not much, just enough so they can jostle a bit when in motion.

Hope that helps.


Edited to add: I've scanned a few books now and the slides are still consistently stopping short of the top. I don't find it too annoying but in the future i will add a second handle such as Clemd has on his scanner. For now, I've been using the counterweight screw eyes when needed.

[Drake Ravensmith]

After having scanned some stuff over the course of several months, I have decided that I was not happy with my camera mounts. They're just too hard to get back into position after being moved and they don't always stay in position after the scanner has been vibrating a bit. Coincidentally, I also decided to try a camera with more megapixels to see if it would improve post processing. I've only post processed one book as of yet and the font was just terrible so I'll have to get back to you on that. In the meantime, this is my new setup.

Finally, with a decent camera!

Drake Ravensmith.JPG (67.41 KiB) Viewed 7709 times

Note: My setup using both tv preview monitors and hi res monitors to view final output was never going to be the way I scanned. I only scan books which are text front to back and the setup time was atrocious so I did one session to see if it would work (it did) and then went to just using the hi res monitors to preview shots.

I did find that my efforts to correct my base board length problem works for hardcovers and not for paperbacks by the barest of margins so I shifted the fixed side of the cradle a half inch to the right.

Needs a little touch up.

Cradle adjustment.JPG (100.26 KiB) Viewed 7709 times

I ended up velcroing the camera switch to a piece of 2x4 and then putting a rubber band on it.

Pedal.JPG (81.75 KiB) Viewed 7709 times

I really ought to remove the pedal since I don't use it but for now the switch sits just left of it and I can use either foot to trigger it.

Pedal placement.JPG (89.49 KiB) Viewed 7709 times

Now for my new camera mount setup. It starts with my new cameras. Canon a650is. You can't really find these cameras new anymore. Googling would leave me to believe that the flip out LCD screen and use of 4 AA batteries versus a dedicated rechargeable made them sought after by people who would have otherwise purchased the more expensive G series. So canon discontinued them. I paid 150 apiece used which is the same price I paid for 2 used a590's. Something I hadn't considered until after I had two was that the flip out lcd screen is prone to breaking leaving an otherwise perfectly good used camera up for sale at a drastically reduced price. Since I use preview monitors, I don't need a functioning lcd and could have saved some money. I still need a backup I suppose...

Check out the reflections on the wood. Imagine how bad that would be without matte black paint.

Canon a650is.JPG (91.67 KiB) Viewed 7709 times

Taping some construction paper to the front of the cameras to prevent reflections was proving to be ineffective. I either had to use too much tape which left the camera tied to the scanner and feeling like a mess or too little and it wouldn't stay put. Now I'm trying rubber bands and they seem to be working quite well.

Crossed taped to keep them from coming off.

New reflection shield.JPG (75.08 KiB) Viewed 7709 times

The bands can be adjusted to access battery door, the controls, etc.

Camera Shield setup.JPG (80.73 KiB) Viewed 7709 times

I started with a level piece of 2x4. I found some cheap Targus tripods that by sheer coincidence are the perfect height when the legs are extended to the first two tracks and then locked into place. I then use some scrap 1/2 inch plywood to keep the legs from being able to slide around. The piece behind the far leg may be removed later as it turns out sliding it forward raises the camera up a little. A shim under the board does the same thing. By another coincidence, a piece of 2x4 screwed to the scanner side of the board sits immediately underneath the conduit clamps I was using for the old camera mounts. This should keep a casual bump from knocking the boards off the ends of the table.

Camera base.JPG (69.1 KiB) Viewed 7709 times

I put some spare weights on to help prevent tipping.

Camera mount base.JPG (83.22 KiB) Viewed 7709 times

I'm doing a fairly ordinary sized paperback so the boards are pulled up front. I have to be carful not to put my arms down on them but so far so good.

Camera mounts.JPG (153.87 KiB) Viewed 7709 times

Since the tripods are sitting on the plywood which in turn is just laying on the very small section of table the scanner isn't occupying, when I want to make a camera adjustment, I move the plywood, not the camera. Slide it to the back for taller books, to the front for shorter. Rotate left and right to line up the text. The tripods do an excellent job keeping the cameras from moving along that axis. My first scanning session seems to have been a complete success although I'll have to pre and post process to know for sure.

Unfortunately, I haven't achieve my goad of a setup where I don't have to touch the cameras. The HQRP ac adapters which were working so well with the a590's are the wrong type for the a650's so I had to get new ones. The first two didn't work at all so I sent them back and got a refund. The second pair (purchased this time from the same seller that sold me the pair for the old cameras) didn't fair any better. The one didn't work and the other would quit after six or seven shots. I'm assuming the vibrations from the scanner were jostling the plug which seems loose on both adapters in both cameras. So I sent them back for refunds as well. At this time I cannot afford to try the canon made ones so I am stuck with rechargeable batteries. The eneloop batteries I used did last an entire two and half hour session scanning six 400 page books so at least I won't have to change them mid scan. If the CHDK battery charge estimate is to be believe (I don't know if it is), then I still had a 40-50 percent charge left.

I also added another device, a SD extension cable.

SD extension cable.JPG (103.57 KiB) Viewed 7709 times

I got these off of ebay for twenty bucks a piece. Note the fake lock tab. Apparently, the Chinese ones off of Amazon have real lock tabs. The a650 is takes 4 AA batteries, therefore it has a long battery door. I just slip the cable into the camera, close it up, and I can remove the memory card without touching the camera except to turn it off first. This is good because the eye fi cards endless memory modes fails every so often. Oddly enough, if one card fills up, then usually so will the second within a dozen or two shots. I've been far too busy/lazy/apathetic to go to the eye fi forums and see if they know why. Sorry. The cables aren't perfect. Since these ones don't have a lock tab, they won't read the memory cards as locked and won't load the SDM. Gerard suggested I switch to CHDK. I used a program called Card Tricks http://chdk.wikia.com/wiki/CardTricks to load it to my cards. Then, I set the cameras to preview mode, turned them on, pressed menu, then up, then right, then ok, and then switched them to shoot mode. This loads the firmware (still temporary, it vanishes when the camera powers off) through the camera itself. The first time you set this up you also have to go into the chdk alt mode (accessed on the a650 by pressing the print? button) and then enabling remote shutter function. Easy breezy.

With the ac adapters attached (before I found out they didn't work) I had a further problem. The cameras will often flash a low battery warning when attached to ac power. You can't update firmware with a low battery even if it only takes a second. The camera manual warns you with a symbol and everything that the camera must be turned off before attaching the ac adapter. So, for now I can have the extension cables or the ac adapters. Since the ac adaptes don't work I think the answer is too clearly beat one's head against the table and curse god for ruining your plans.

Apologies for this repeat photo. I didn't put it there and I can't seem to remove it.

[rjohs]

As for the keyboard slides...I'm not sure why but the slides were occasionally stopping an inch or so from the top.....

I believe the problem you are experiencing is due exactly to the fact that you are using keyboard slides. Think about how you use them on a desk, when you slide the keyboard out, at the very last inch or so there is a "stop" that you pull the drawer past before you reach the full extension. This is designed to lock the drawer in the open position so that it doesn't slide in as you rest your hands on the "wrist rest".

I'm starting my build this week and hope to incorporate most of yours and Clemd's improvements. Thanks for all of your hard work in documenting your build.

Rich

[Drake Ravensmith]

Interesting... That would imply that the problem could be solved by installing them upside down so when the platen is at the rest the slides are fully extended. I'm assuming the weight could nudge past that occasional hiccup.

[rjohs]

Even better, mount your slides upside down as you suggest, but just low enough that when the platen is at rest it hasn't reached the "stop" at full extension. You will lose that one inch of travel, but you'll never get the "hiccup".

The other option is to not use keyboard slides. There are several different styles of drawer slides available, that mount in all different configurations. They fall into these general types:

center/undermount - these mount to the under side of the drawer and cannot be seen from the side once installed.

side mount - these mount to the side of the drawer, centered vertically and can be seen entirely when installed

bottom mount - these mount to the corner of the drawer, screwed to the bottom of the drawer and to the side of the cabinet box. This is essentially the same as a keyboard drawer, but would not have the same "stop" as a keyboard drawer. This is the type to use to avoid the problem you are having.

The last thing to look for in a drawer slide is the extension. There are 3/4 and full extension slides. As the name implies you get more travel out of a full extension slide. On the cradle you can use a 3/4 extension, due to the limited nature of the cradles movement. On the Platen however, I would think you would want a full extension drawer slide to take full advantage of the slides travel, to get the platen as far out of the way of the book as you turn the pages.

Rich

[Drake Ravensmith]

We used keyboard slides over drawer slides because the tabs create a sort of automatic alignment. There really is no great danger of putting one or both of them on wrong and potentially wrecking the wood trying to get a perfect fit. As I recall, the slides were difficult to find. We had to order them online and sizes were limited. The problem we have with them now is we lose an inch or so of travel every so many lifts. That inch is needed since they don't travel very far. If we put them on upside down an inch lower, then we've lost that lift forever with no gain.