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

New Standard Build Thread (mechanical trigger)

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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Gerard
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Re: New Standard Build Thread (mechanical trigger)

Post by Gerard » 16 Jan 2011, 18:58

dtic wrote:I tried a bare bones servo trigger. It is pretty reliable so far. The metal strips I've secured the spring and camera mount to are bendable, which makes it easy to fine tune the camera button position.
12.jpg
I have removed the electronics from the servo, just like in your setup, and use a battery for power and a switch.
The spring used above is of course overkill but was the only one at hand. The servo is so small that I bet a safety pin plus a rubber band would work as well. The servo only needs to be pulled back up a few milimeters.
this metal strips are a nice idea i will buy next time some, i would suggest for the long term to have a mechanical stop the servos are able to make some pressure and this maybe could kill the trigger button in the long term

@jck57 the downsize is that cheap cams does not allow you to set parameters manual, chdk fixes this problem and then you will have usb remote triggering also

hacking with chdk seams for me a lot easier and you earn a lot of extras, but if you have a expensive camera and don't won't to play with ptpcam or similar software, i can say it's working reliable, i spend for 2 a495 75€ per pice and have 10MP per page, but if you need a dslr for private use and hoping an new software developments that will make single camera scanner easy to use (dewraping currently makes huge steps)
then you can decide? 150€ which can be invest in a dslr

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jck57
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Re: New Standard Build Thread (mechanical trigger)

Post by jck57 » 16 Jan 2011, 21:19

Gerard wrote:
@jck57 the downsize is that cheap cams does not allow you to set parameters manual, chdk fixes this problem and then you will have usb remote triggering also

hacking with chdk seams for me a lot easier and you earn a lot of extras,
I have the Canon A480 and use ABBYY Finereader 9.0 Pro. Besides remote trigger, which features of CHDK will help me?

I don't like the reports of glitches of CHDK, also that the script may need to be reloaded, etc. Then there is double firing the trigger for every shot (first to focus and second for the shutter), and the start up procedure required.

I may be wrong but it seems to me less problematic to use servos to fire the cameras. By partially depressing the shutter I can focus my camera at the first page, and then lock the focus for the rest of the book. Locking focus and light control speeds up multiple shot cycles.

dtic
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Re: New Standard Build Thread (mechanical trigger)

Post by dtic » 20 Jan 2011, 15:30

Hi jck57. I don't see any really big drawbacks so far. Some smaller issues:
1. It takes some time to construct an object that secures the servo and the camera.
2. In my cases, last time I tested that setup the servo had gotten disaligned slightly since the use before. I had to bend the metal strips very slightly by hand and then it was good to go again. I guess that type of adjusting will need to be done now and then.
3. The servo might damage the camera button like Gerard mentioned. I'm not sure how big that risk that is though, especially if using a really tiny and weak servo. We'll see after longer testing I guess.

A big plus is that a mechanical trigger should work with any camera.

anvit2a

Re: New Standard Build Thread (mechanical trigger)

Post by anvit2a » 04 May 2011, 06:43

Do you guys pulse the servo or how do you do it?
i mean is there any other than power servo and a switch in this?

i was looking at a servo like this:
http://cgi.ebay.co.uk/2X-Micro-9g-Servo ... 415901b108

will it work? are they strong enought? i plan to do a double trigger for two cameras.

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jck57
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Re: New Standard Build Thread (mechanical trigger)

Post by jck57 » 04 May 2011, 09:05

anvit2a wrote:Do you guys pulse the servo or how do you do it?
i mean is there any other than power servo and a switch in this?

i was looking at a servo like this:
http://cgi.ebay.co.uk/2X-Micro-9g-Servo ... 415901b108

will it work? are they strong enought? i plan to do a double trigger for two cameras.
Another option is a solenoid. These look like they might work.

http://www.jameco.com/webapp/wcs/stores ... 1919203_-1

aeturneus
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Re: New Standard Build Thread (mechanical trigger)

Post by aeturneus » 14 Jan 2012, 15:57

Aren't vibrations an issue with mechanical triggers? Perhaps not a huge issue, but electronic triggers seem like a cleaner solution to me.

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Gerard
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Re: New Standard Build Thread (mechanical trigger)

Post by Gerard » 14 Jan 2012, 18:20

maybe, but i can't see any blur or big movements, the fist design hat a problem with movements, but i made the base bigger an let foam press the button

i prefer also electrical triggers, but the solution with chdk has also problems, you need to buy old cameras to have chdk support and no one can say you if the cameras in the future will be also hack able one can say you if the cameras in the future will be also hack able

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