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
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.
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I looked at the pictures and was puzzled by the counterweight but it came clear with the video. What I am seeing in the video is a lot of movement on the two side supports and the cradle. They jiggle and move side to side and this is obvious with the movement of the platen. What is more interesting is that your back support seems very solid. I believe that is from the structure you made with the two slides and the angled material.
The scans seem very nice so the result is worth the work. I like your ideas with the cameras attached to the scanner and the overall prototyping is very nice. I believe this will help me get what I want out of my portable scanner build I am thinking about. Thanks for the tip on the camera mount!
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You are right, the thing wiggles side to side about a 1" one way or the other when the platen is raised, but once lowered it doesn't appear to move at all. For instance, I just scanned a 200+ page book, loaded the images into Lightroom and did a batch lens adjustment and crop (about 30 seconds to set the parameters). I ended up with basically perfect images (if you've read some of my other posts you know I'm pretty particular about quality) and could have avoided ScanTailor altogether if I had a nice way to binarize the color/grayscale images and make mixed mode files for the few pages with color illustrations.
The reason for this precision is having the cameras mounted to the platen: they are always the same exact distance from the platen and if the book doesn't slide around on the cradle then they are in the same exact relation to the book as well. The only thing that can't be overcome is that as you move through a book usually you can get deeper into the gutter at the beginning and end than in the middle, so this means that the images from the middle of the book are usually about 1/8" closer to the inside margin than the outside pages (though there are ways to combat this). So you need ScanTailor to make things *perfect, but you can get something really darn nice without it too.
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Doesn't the use of a counterweight defeat the purpose of building a lightweight scanner? You'd probably be better off using a tension spring. It's lighter, cheaper, and it would reduce inertia as well.
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jacko wrote:Doesn't the use of a counterweight defeat the purpose of building a lightweight scanner? You'd probably be better off using a tension spring. It's lighter, cheaper, and it would reduce inertia as well.
I would love to use a tension spring, but the ones I got at Home Depot didn't work at all. The 10lb spring just bent out of shape, the 15lb was pretty much the same, to 20lb and 25lb springs were too strong and made it hard to pull the platen down (they also made all sorts of annoying dinging sounds), also they got harder to stretch the further I pulled down the platen. What type of spring system would you recommend to provide even lifting power of about 5-10 lbs for a distance of ~10"? My counterweight provides smooth and even resistance (it's 5lb), is it possible to get that with a spring? I really appreciate any wisdom you have on this issue, since I wanted to use a spring from the beginning, but it didn't work the way I tried to do it.
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a rubber tarp should be more silent, and you can use a pulley to allow a strong tension spring (changing force against way) , a spring on a pulley hook (not the rope) could do the job
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Shaknum wrote: I went with a 100% platen which really helps with reflections, and you can even use the camera's flash for much of the lighting. I may modify it to have a smaller V, perhaps 80% in the future since that seems to be better for the books, and it would cut down a bit in size.
Do you mean 100 degrees ?