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auto page turner prototype

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.
dtic
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Joined: 06 Mar 2010, 18:03

auto page turner prototype

Post by dtic »

a.jpg
a.jpg (87.2 KiB) Viewed 20466 times
See attached video (zipped .mkv since upload form didn't allow mkv). The "big finger" is a rubber eraser. The "small finger" is a thick drinking straw. To use a double platen you'd need two (properly timed) forces. Reliable finger action is a challenge but the device now performs fine on a 30 page test run.

edit: youtubed video here
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Hasher
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Re: auto page turner prototype

Post by Hasher »

Well it certainly is proof of concept , keep up the good work. :D
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JonEP
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Re: auto page turner prototype

Post by JonEP »

That is so cool!
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daniel_reetz
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Re: auto page turner prototype

Post by daniel_reetz »

PHENOMENAL!!! May I put your video on YouTube, so I can post it to the News page??

Seriously, I couldn't be more excited about your work. Do you know how many jillion times I've been asked about page turning? I'd all but given up on it... and here comes a working prototype! Cheers, dtic.
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Misty
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Re: auto page turner prototype

Post by Misty »

Wow, that is awesome!! It's great to see someone build an actual, working auto page turner.
The opinions expressed in this post are my own and do not necessarily represent those of the Canadian Museum for Human Rights.
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daniel_reetz
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Re: auto page turner prototype

Post by daniel_reetz »

I must have watched the video like 20 times now... and I just love when it seems to ... almost... miss the page, but then comes back and successfully turns.

What are the joints made of? It kinda looks like tape...
dtic
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Re: auto page turner prototype

Post by dtic »

Sure, post away Daniel! :-) I'd be honored to see it there. I hereby stamp a CC by-nc-sa license on it.

Brief explanation of some parts:

Yes, the "big finger" joint is just electric tape and a piece of plastic tube. The tube slows the downward movement of the finger. Without that it fell down too hard. Tape is no durable solution of course, but I had to fine tune the distances and angles a lot when testing so that was the way to go at this stage. The finger segment cores are just metal rods. The metal sinker right above the eraser add enough pressure for the eraser to grab the page.

The hardest part was the "small finger". That extra finger is vital, without it the page falls back when the big finger lifts off. The small one is just a big screw with a loop screw on top and a bolt and a lot of tape as joint. There's also a screw in the taped part of the swivel straw to make it stiff. Timing was really tricky. To get it to snap into the book only after the big finger has moved the page enough, then stay there so the page turns over and stays put and finally snap out before the platen hits. For that I tied two wires to the swivel. One pulls it CCW when the platen is near the top, the other pulls it CW when the platen is almost down. The rest of the time both wires slack and so the swivel stays put. But as you can see the swivel still tilts sideways a bit too much at the moment and can easily get uneven. It is the weakest link in the setup so far. I first tried a fixed joint (only allowing circulation and no sideways tilting) but then the (very thin cotton) wires snapped.

But that whole problem occurs only because I don't have separate motors for each moving part. I had no small motors at home and lack electronics skills. But I think (properly timed) motors will bypass that problem. (It will, sadly, also make the movements less snappy and without all the wires the device would lose some of its current Rube Goldberg style. :-)

To later on get a device that can autoscan a whole (thick) book some automatic mechanism would also be needed for both moving the book holder sideways (for the platen to keep hitting center) AND to adjust the big finger slightly since the book's right hand side "page pile" is higher when scanning the beginning of the book and that affects where the finger hits the page. If it gets close to the right edge or to the center then the page grab fails.

The bad news is that I don't have much time to improve the device right now. I'll get back to it some time this summer. But I hope someone else gets inspired and remixes this setup for the better right now!

One last thing unrelated to the page turning: several of the scanner builds I've seen here use drawer slides under the book holder for left/right movement. I didn't have an extra spare slide so I just used two U shaped aluminium rods under it. Then I screwed similar rods to the device "floor board" thereby making a straight track in the space between them. That allows left/right movement (only) and has enough friction to stop accidental side slide. Maybe it's been done on other builds already. But I haven't seen it so I thought I'd be worth mentioning.
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daniel_reetz
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Re: auto page turner prototype

Post by daniel_reetz »

LeissKG
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Re: auto page turner prototype

Post by LeissKG »

A version with separate motors will not necessarily be less snappy. For the two fingers i would suggest RC-Servos. The forces at the little finger should be small enough that almost any servo should do. The bigger finger may possible need a beefier servo but i doubt it. For control there are some easy to learn micro controller platforms like the Basic Stamp or the Arduino. I know that at least the Arduino has a library to directly interface multiple RC-Servos. I would also add a light barrier at the platen movement so that the controller knows if the platen is out of the way. The Arduino could also trigger the cameras.
An assembled Arduino clone should costs about $30 and an servo around $10 depending on size and force.

Some links regarding Arduino and Servos
http://www.arduino.cc/playground/Learni ... rvoExample
http://principialabs.com/arduino-python ... o-control/

A link collection for all kind of information about Arduino

http://www.freeduino.org/

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StevePoling
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Re: auto page turner prototype

Post by StevePoling »

In the video, pages are turned from right to left, and I wonder about two things:
1) what prevents two pages on the right from sticking together and being flipped simultaneously?
2) After the page is turned, what prevents additional pages from falling over from right to left before the platen can be lowered?
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