The New "Standard Scanner"

[bchapman]

2 1/2" bolts. 1/4 20. These bolt 2x4's together. You need 4 of them -- for the column. This picture is incorrect. Imagine that they are 2.5" long, plz.

Actually, I think they do need to be 3.5" or 4" to go through the two 2x4's. 1.5 + 1.5 = 3 inches. It might be better to just say 4" so that those are the only size bolts being purchased, although that does leave a fair amount of thread exposed.

I'm about half-way done building from this design. It's my first build and I'm having a lot of fun putting it together. Thank you for all of the information and hard work!

Ben

[daniel_reetz]

Thanks for the correction, Ben... I think you're exactly right.

I spent this last weekend in Boston at a conference put on by O'Reilly inc. While talking to people there, I learned a lot about authoring new ebooks... I have a plan to make these plans into an ebook (especially allowing people with suggestions like yours to add them). I'll share more, soon, just as soon as I get back from Vancouver.

[hank]

So, thanks Daniel! I've managed to build a close approximation of the new standard scanner! Yet, since you said your Y-adapter doesn't work, I've been searching the forum trying to find the best way to set up a trigger for my A590s. I'm probably going to do this. I'm wondering which trigger you're planning on including in the final instructions. I'll post pictures when I'm totally done, just have to get the electronics and software working, but most of the plans were very well laid out and easy to complete!

[daniel_reetz]

Great news, Hank, and I can't wait to see what you've done.

I was really hoping to come up with a nice no-solder solution for the cables. I think there's going to be some kind of no-solder solution involving a bunch of USB adapters, but otherwise, the cable you linked seems like the best approach. I'd go for it if I were you. It's a great way to do things.

[hank]

I did that, and instead of buying an push-button switch, I took apart an old ball mouse and used the left click button. It works beautifully. I'm going to have to figure out how to mount it all on the frame of the scanner, though, which will take some effort. For now, I just electrical taped it to the wood. With CHDK running on both cams, it works wonderfully.

The scanner, as it currently exists


The mouse, reduced to PCB


There was some soldering involved in the above photo. I soldered the +5v together and wrapped in electrical tape, then soldered the +5v leads onto either side of the button. That way, when the button is depressed, voltage is sent to the USB hub. In the video below, you can see me activate CHDK on both A590s, and proceed to use the hub setup to take a few pictures.

Resultant Pages (Rough, some glare)




YouTube VIdeo of the functionality!

[Pagnol]

I see that you've added additional panes at the sides of the platen in order to strengthen it. I think I'll do the same, it's not sufficiently solid without them especially if you've chosen acrylic glass that's only 2 mm thick.

There are quite some reflexions visible in the pictures you're showing. It just came to my mind that amateur and professional photographers sometimes use so-called polarizing filters. If you "cover" your lens with one of these, reflexions will be filtered due to their different polarisation. I've never used them though and their quite expensive. I'm wondering whether anyone's used them for book scanning purposes? Might improve the quality of your scans, I guess.

By the way: nice scanner, appears to be neatly built (different to mine in that regard).

[Misty]

We've talked about polarizing filters before, I think. They look quite promising. The only major problem (aside from the price, and $50 each really isn't too bad) is that the filter reduces the amount of light reaching the sensor by about half; that necessitates using a longer shutter speed, which unfortunately increases the possibility of minor camera jitter artifacts being visible in the final image.

I'm also not familiar with whether the digicams used by most people, like the A590, have filter mounts. That might pose a bit of a challenge. Filter adaptors are available for higher end compacts like the Canon G10/11 and S90, but I'm not sure if you can buy one for the A590.

Edit: I probably should have done a 30-second Google search before posting. It looks like there are filter adaptor kits. Someone here says they can be as cheap as $20 for a 52mm adaptor. Not sure if it introduces any vignetting at particular zoom ranges.

[piticu]

Not sure if it introduces any vignetting at particular zoom ranges.

Absolutely NOT. Vignetting will be a problem if you use smaller filter on a larger lens (smaller/larger in regard of diameter).

[Misty]

Yes, that's what I meant. I don't have an A590, so I don't know what size the lens is. I do know that using 58mm filters on a PowerShot G10/G11 can introduce vignetting, according to Lensmate, who produce adaptors for those cameras. They say that those cameras require a 72mm adaptor to avoid vignetting at all focal lengths. Is the A590's lens small enough that 52mm filters won't present a problem?

[hank]

I see that you've added additional panes at the sides of the platen in order to strengthen it. I think I'll do the same, it's not sufficiently solid without them especially if you've chosen acrylic glass that's only 2 mm thick.

Indeed! The instructions could benefit from something like that. I think I'll replace it with something a little more solid than 1/2"x1/2" MDF in the future, as the current stuff is splitting where I drilled and coming off. But at least it strengthens the platen. Also, make sure to note how far down your platen will go when you mount it to the riser. Mine doesn't quite go down far enough to give sufficient pressure to the pages, so I may have to lower it. No big deal, just a few minutes of work.

There are quite some reflexions visible in the pictures you're showing. It just came to my mind that amateur and professional photographers sometimes use so-called polarizing filters...

As a photographer, I happen to have a CP (circular polarizing) filter. They're great for the same types of things polarized sunglasses are good at - defeating reflections from hazy scenes, water scenes, sky shots, etc. The only reason that glare is there is because I had the scanner in a bad part of the room. Now that I moved it on top of the dryer, everything works better. I also made sure to set my A590s to Tungsten for white balance, and changed the auto-focus to AFR1 or something (too lazy to look now), since Center would screw up pages that lacked lots of text, and they ended up out of focus. Thanks for the idea though. You can indeed use a 52mm polarizer on the tiny A590 lens if you like, but you generally shouldn't need it. If you get your hands on one, try looking through it at an LCD monitor and turning the filter in circles. The screen light will disappear. It's awesome.

By the way: nice scanner, appears to be neatly built (different to mine in that regard).

Yeah, I spent some serious time on it, and considering I built it using only a Skil circular saw, a cordless drill, and an army of Quik-grips, it came out alright! Learning how to cut acrylic was an adventure, as I obviously couldn't read any instructions first

I've finished an entire book now, and am trying to process it all in Linux. I'm currently using ScanTailor, and it's working great. I'm also using the DeWarping java program from Rob - thanks Rob! It works great!