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

Camera Triggering

Everything camera related. Includes triggers, batteries, power supplies, flatbeds and sheet-feeding scanners, too.
Abarbour
Posts: 13
Joined: 30 Aug 2012, 17:03
Number of books owned: 2000
Country: Canada

Re: Camera Triggering

Post by Abarbour » 25 Sep 2012, 13:30

Found an interesting article on creating electronic triggers for a few DSLRs....

http://www.hiviz.com/kits/instructions/rsr_inst.htm

And in case this ever goes down.... I have printed to PDF and it is up on GoogleDocs for you.... https://docs.google.com/open?id=0B52Hoc ... k1EejhKQ1k

I am including the model numbers - in the event anyone is searching for specific cameras....
Canon EOS 7D, 10D, 20D, 30D, 40D, 50D, 5D Mark II, 1Ds Mark III, 1D Mark IV, 1D Mark III
Canon EOS Rebel series, EOS 60D, 300D, 350D, 400D, 450D, 500D, 550D, 1000D, Powershot G10, G11, G12
Nikon D1/D2/D3 series, D100, D200, D300, D300s, D700, F5, F6, F100, F90, F90x, Kodak DCS-14N, Fuji Finepix S3pro, S5pro
Nikon D90, D3100, D5000, D7000
Sony Alpha A100, A200 ,A290, A300, A350 ,A380 ,A390, A450, A500, A550, A580, A700, A850, A900SLT-A33, A55, Minolta Maxxum 5D, 7D, 7, 9xi, 7xi, 5xi

Just tried it with an A100 - worked like a charm....

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RyanGuy
Posts: 2
Joined: 14 Sep 2012, 23:32
E-book readers owned: iPad, kindle
Number of books owned: 500
Country: United States
Location: Chico, CA
Contact:

Re: Camera Triggering

Post by RyanGuy » 07 Oct 2012, 02:38

My standard build kit is on its way, so in the mean time I'm left playing with my cameras. I'm curious, has anyone else used van de Kamp switches on a standardbuild Hackerspace Scanner?

Here are the basic switches he sells :http://www.flickr.com/photos/fvdk3d/4823557573/

My thoughts were to either (1) go wired, use an A or D switch with long cables to run from the cameras down to the handle (allowing a thumb-press to trigger the switch. OR (2) look into one of the wireless options to cut down on the cables to the moving parts. Wireless remote could also be activated with a thumb press.

I'm not in a hurry to order my switch. I'm currently planing on waiting until I have my kit assembled to draft out the triggering plan. I'd just like to see what others have had success with thus far.

TomHorsley
Posts: 96
Joined: 30 Jan 2011, 10:39

Re: Camera Triggering

Post by TomHorsley » 26 Nov 2012, 20:37

In my ongoing work on building my android camera app, I've obtained a Samsung Galaxy Camera, and it has a new trigger technique available even without running my custom camera app: Voice control. If there isn't much noise in the environment, and you turn voice control on, you can say "shoot" and it will take a picture (you can say other things too, like "zoom in"). You might wind up with a raw throat after scanning a thousand page book though :-).

tresho
Posts: 29
Joined: 14 Dec 2009, 04:51

Re: Camera Triggering

Post by tresho » 27 Nov 2012, 08:12

I don't see much of a feature added by having the operator's voice triggering the shutter. Either push buttons or photoelectric triggering seem the way to go. Should be fairly easy to set up a light beam apparatus -- after lining up your page, pass your hand through the light beam & circuitry will then trigger the shutter. An operator should be able to wave his/her hand a few thousand times without fatigue or repetitive stress injury.

TomHorsley
Posts: 96
Joined: 30 Jan 2011, 10:39

Re: Camera Triggering

Post by TomHorsley » 27 Nov 2012, 11:47

tresho wrote:I don't see much of a feature added by having the operator's voice triggering the shutter. Either push buttons or photoelectric triggering seem the way to go. Should be fairly easy to set up a light beam apparatus -- after lining up your page, pass your hand through the light beam & circuitry will then trigger the shutter. An operator should be able to wave his/her hand a few thousand times without fatigue or repetitive stress injury.
Me either actually, but it does work, and at least it wouldn't cause any vibration of the camera like mechanical triggers, unless you yell really loud :-).

The app I'm writing (AndyScan: http://home.comcast.net/~tomhorsley/sof ... yscan.html) is designed to support lots of different trigger techniques. The one I think will be most useful is light level - once you get the page turned, you bring up the lights to illuminate the page, and the camera notices the change and takes the picture. I've also got it doing motion detection, so after you are finished turning the page and the scene in front of the camera goes quiet again, it can take the picture. (Not finished yet, still need to add some calibration code so you can actually make use of light or motion, but it definitely seems able to do the detection).

tresho
Posts: 29
Joined: 14 Dec 2009, 04:51

Re: Camera Triggering

Post by tresho » 27 Nov 2012, 13:09

I would think the simplest light-related trigger would be to pass a hand through a light beam aimed at a photo cell. Drop in illumination of the photo cell can easily be used to fire a shutter-triggering circuit. This is a binary switch (whatever the circuitry is) and under the operator's control.

jera2
Posts: 11
Joined: 28 Jul 2011, 00:09
E-book readers owned: Kobo
Number of books owned: 1200
Country: Canada

Re: Camera Triggering

Post by jera2 » 29 Nov 2012, 05:24

I've been using a motion-detection trigger for my book scanner, and it works quite well.

The way it works is that it first focuses the camera(s) and then begins the motion/no-motion state-machine. This state-machine loop waits for motion (lifting the platen, changing the page) and then waits for a period of no motion (settle), after which it takes a picture, waits one second, and repeats ad nauseum.

To get focusing to work well, I always place the book in the scanner with both pages showing text. Once I hear the cameras click the focus and take the first image, I flip the book back to the cover and begin my scan. That is the jist of my workflow.

I have two Canons, an A490 and an A495, and they run this CHDK script:

Code: Select all

--[[
rem  idleShot.lua
rem
rem  Shoot when motion stops, by Jerry Penner
rem  Holds AF Lock until script ends

@title Shoot Once When Idle
@param d IdleTimeout (ms)
@default d 2000
]]

sleep( 250 )
press( "shoot_half" )
repeat
  p = get_shooting()
until p == true

release( "shoot_half" )
set_aflock( 1 )

a=6         -- columns to split picture into 
b=6         -- rows to split picture into 
c=1         -- measure mode (Y,U,V R,G,B) <96> U=0, Y=1, V=2, R=3, G=4, B=5
            -- d is set as a parameter:  maximum time to wait for motion (ms)
e=200       -- comparison interval (msec) 
f=5         -- threshold (difference in cell to trigger detection)
g=1         -- draw grid (0=no, 1=yes)   
h=0         -- not used in LUA 
i=0         -- region masking mode: 0=no regions, 1=include, 2=exclude
j=0         --      first column
k=0         --      first row
l=0         --      last column
m=0         --      last row
n=0         -- optional parameters  (1=shoot immediate)
o=2         -- pixel step
p=0         -- triggering delay (msec) 

if (d < 1 or d >10000) then
  d = 10000
end

while 1 do
  repeat
    zones = md_detect_motion( a, b, c, d, e, f, g, h, i, j, k, l, m, n, o, p )
  until zones > 0

  repeat 
    zones = md_detect_motion( a, b, c, d, e, f, g, h, i, j, k, l, m, n, o, p )
  until zones < 1

  shoot()
  sleep( 1000 )
end

set_aflock( 0 )
The d parameter controls how long the motion-detector waits for motion. I've left it at 2 seconds (2000 ms), and I think I could probably shorten it without issue. My camera mounts are quite stable, so there is no problem with them vibrating after lowering the platen.

Edit: I have been about to scan 250-300 page books in about 20 minutes with this setup.

tresho
Posts: 29
Joined: 14 Dec 2009, 04:51

Re: Camera Triggering

Post by tresho » 29 Nov 2012, 12:30

Looks like your subroutine might even work with no scanner device at all, simply by mounting the camera on a tripod looking down on the book and then flipping the pages by hand. Did you ever try that?

Abarbour
Posts: 13
Joined: 30 Aug 2012, 17:03
Number of books owned: 2000
Country: Canada

Re: Camera Triggering

Post by Abarbour » 02 Dec 2012, 09:57

The one I think will be most useful is light level - once you get the page turned, you bring up the lights to illuminate the page, and the camera notices the change and takes the picture.


not a criticism.. more of an observation.. If I was the operator I would feel like I needed a drink in my hand and some pulsing music to go with stroboscopic effect of the lights constantly going off and on.... :)

Javier_Romagosa
Posts: 3
Joined: 14 Aug 2012, 04:31
E-book readers owned: Pantech Element LP4800
Number of books owned: 1
Country: Spain

Re: Camera Triggering

Post by Javier_Romagosa » 03 Dec 2012, 07:40

Good morning:


Maybe you would like to take a look at the mechanical triggers I had devised for my Hackerspace Scanner. They are governed by the bicycle brake handle supplied in the DIY Hackerspace Scanner Kit.

Image

Image

Image

Image

Image


Best regards,



J. Romagosa

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