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

create an auto switch with optic sensor

Everything camera related. Includes triggers, batteries, power supplies, flatbeds and sheet-feeding scanners, too.
jakegaisser
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Re: create an auto switch with optic sensor

Post by jakegaisser » 03 Mar 2010, 18:35

I actually have 2 or 3 dead printers that have not been thrown out yet. I will be dissecting them later.

I have done quite a bit of planning and revising over the last 2 days. I have not even cut a single board yet, but I will probably be doing some cutting today.

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daniel_reetz
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Re: create an auto switch with optic sensor

Post by daniel_reetz » 03 Mar 2010, 18:41

Great news, looking forward to your build thread. Hope your printers are chock full of good parts.

jakegaisser
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Re: create an auto switch with optic sensor

Post by jakegaisser » 03 Mar 2010, 18:51

I don't have a whole lot to work with, so the design will be really simple but functional and at the same time very cost effective. we already bought a Powershot A470 about 1/2 a year ago as our main daily-use camera... we just bought the second A470 camera lately for $20 shipped, it's lcd screen is broken but the camera still functions, so its a perfect candidate for the second camera.

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Re: create an auto switch with optic sensor

Post by StevePoling » 03 Mar 2010, 19:03

If you're throwing an arduino and sensors at the problem, consider this: an accelerometer notices you've moved the platen (to arm a circuit), and notices when you quit fussing with it (to fire).

Add an accelerometer on each camera to confirm that it snapped to light a green LED. With this, you'd lift platen, turn page, release platen and wait for a green light from both cameras.

jakegaisser
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Re: create an auto switch with optic sensor

Post by jakegaisser » 03 Mar 2010, 19:08

StevePoling wrote:Add an accelerometer on each camera to confirm that it snapped to light a green LED. With this, you'd lift platen, turn page, release platen and wait for a green light from both cameras.
I like the idea of having LED that lights up once the camera has fired, what exactly is an accelerometer, and where can i buy or salvage one for cheap/free?

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daniel_reetz
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Re: create an auto switch with optic sensor

Post by daniel_reetz » 03 Mar 2010, 19:14

StevePoling wrote:If you're throwing an arduino and sensors at the problem, consider this: an accelerometer notices you've moved the platen (to arm a circuit), and notices when you quit fussing with it (to fire).

Add an accelerometer on each camera to confirm that it snapped to light a green LED. With this, you'd lift platen, turn page, release platen and wait for a green light from both cameras.
Problem with accelerometers is that there is no free lunch. You'd need to get Kalman filters up and running on the Arduino to make that noisy data useful... when you could accomplish the exact same thing with two switches (IMO). I like the idea of arming the camera on the upstroke, and firing it on the downstroke... that's great.

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IcantRead
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Re: create an auto switch with optic sensor

Post by IcantRead » 04 Mar 2010, 14:34

I like the accelerometer idea. The problem i have with the optical switch, is that were do you mount it? No book is the same thickness, so therefor if you put it to high then it will take it to soon. Then on the other hand if you put it to low it wont trigger on some books. Likewise the piezo would not work for small books like magazines or comic books. The accelerometer, though would most likely work for everything. I still think i'll try out a piezo just because i have a few i'm not using around. Maybe if I put them on the book cradle instead of the spine it will work better.

jakegaisser
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Re: create an auto switch with optic sensor

Post by jakegaisser » 04 Mar 2010, 14:36

dont mount the optic switch at the stopping point, instead mount it a little higher (maximum thickness book height) as a pass through type function. and then just wire in a delay circuit.

StevePoling
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Re: create an auto switch with optic sensor

Post by StevePoling » 07 Mar 2010, 22:40

daniel_reetz wrote:You'd need to get Kalman filters up and running on the Arduino to make that noisy data useful... when you could accomplish the exact same thing with two switches (IMO). I like the idea of arming the camera on the upstroke, and firing it on the downstroke... that's great.
Are you sure a Kalman filter is required? I figured all you'd need is a low-pass filter and something that just looks for some energy.

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