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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create an auto switch with optic sensor

Post by jakegaisser » 03 Mar 2010, 00:30

How hard would it be to create an automatic switch that detects the movement of the platern and once it sees that it has stopped, take a picture.

http://www.atiz.com/autoswitch/

Afish
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Re: create an auto switch with optic sensor

Post by Afish » 03 Mar 2010, 02:38

It might be easier and cheaper to try for timed lapsed capture rather than Auto capture with an optical switch. Although I don't know how one would send a 5 volt signal every 2 to 3 seconds to the camera. Their optical capture switch is a second generation product so there must have been a considerable amount of refinement involved.

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IcantRead
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Re: create an auto switch with optic sensor

Post by IcantRead » 03 Mar 2010, 15:18

I was planning on doing this with an arduino board. Although instead of an optical sensor, mine would use a piezo sensor under the book. That way it would only take a picture when there was enough pressure on the book. There would be a pressure reset button, this way if you needed more pressure for one book and another pressure for another it would compensate. This could be implemented to the button that is already made for the cannon cameras, you would just use one of the outputs on the arduino to send 5v.

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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, 17:45

It's definitely not hard, but it brings a lot of problems. You don't want the cameras to go off the instant the beam is broken, so you need to program a delay. You don't want the cameras to go off unless the book is properly pressed, so you either need very reliable hardware or a piezo strip as ICantRead mentions.

Personally, I think the best way to keep hands free, if you don't like the existing design, is a footswitch. If you search eBay for "tatoo switch" there are dozens of very cheap switches.

jakegaisser
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Re: create an auto switch with optic sensor

Post by jakegaisser » 03 Mar 2010, 17:52

I would imagine that it would be relatively easy to create a delay using a 555 timer which can be bought for less than $1

http://en.wikipedia.org/wiki/555_timer_IC

I really like the idea of an optic switch. I don't want to fiddle with getting a button to align with the downward platern, or a button or foot switch.

the weighted trigger is not a bad idea, but I think an optic switch with a delay circuit would probably give the most flawless results.

jakegaisser
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Re: create an auto switch with optic sensor

Post by jakegaisser » 03 Mar 2010, 18:02

you know... you might even be able to use some of those optic laser things that automatic garage door opener/closers use.... and I bet you could get these for free or close to nothing if you looked around.

jakegaisser
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Re: create an auto switch with optic sensor

Post by jakegaisser » 03 Mar 2010, 18:11

I got to thinking of the cost of the optical part of it. and that would cost a bit... then i got to thinking of other types of sensors that could give me the same results... I found this: http://cgi.ebay.com/ws/eBayISAPI.dll?Vi ... 0432104939

its a magnetic switch, the type used for burglar alarms. I am thinking I will use something like this in combination with a delay circuit.

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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, 18:28

Actually, I have dozens of optical break sensors. They are super cheap, you can find them in any printer or in mouse scroll-wheels. I think the official name is photointerruptor. They look like this.

jakegaisser
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Re: create an auto switch with optic sensor

Post by jakegaisser » 03 Mar 2010, 18:30

ooooooooo! very good to know! thank you :)

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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, 18:33


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