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

Dual Cameras on Kit with Canon + CHDK

Everything camera related. Includes triggers, batteries, power supplies, flatbeds and sheet-feeding scanners, too.
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atarkri
Posts: 14
Joined: 08 Jan 2011, 13:29

Dual Cameras on Kit with Canon + CHDK

Post by atarkri » 28 Aug 2013, 22:29

I happen to have two Canon A540s that I've modified by hooking a wire up to the 2xAA battery input to provide power from a pc power supply.
modified_a540.jpg
The kit had an AC plug for the overhead light, so I decided to "do as they do in Rome" and use the bulky pc power supply to power both cameras, as well as trigger them:
scanner_front.jpg
scanner_side.jpg
I had two unknowns:
(1) Will 3.3V trigger both cameras?
(2) How can I run all of that wire without it getting tangled/in the way?

(1) Was easy to test, applying the same 3.3v that powers both cameras to the USB ports successfully triggers them, I used an easy-to-press power button from an old computer:
handle_detail.jpg
(2) Required some engineering, I used the pivot point of the handle to erect a small structure that would guide the wires:
holder_detail.jpg
I also have some pics of the prototypes, and the artwork for a laser cutter or similar cnc machine:
current_holder_epoxied.jpg
The first version I built. Requries epoxy to hold it to the hex head.
better_holder_setscrew.jpg
My current version. It uses a set-screw to hold the structure to the hex head.
Image

ycpdan
Posts: 22
Joined: 03 Oct 2011, 16:10
E-book readers owned: iRex / Kindle DX/ Nook
Number of books owned: 300
Country: USA

Re: Dual Cameras on Kit with Canon + CHDK

Post by ycpdan » 17 Nov 2013, 23:22

And did the 3.3v work to trigger the camera's at the same time?

Working on the same setup Dual Cameras on Kit with Canon + CHDK and can't seem to find what the min voltage is to trigger the camera's?

Is it just a on /off switch?

vitorio
Posts: 138
Joined: 30 Oct 2010, 23:56
Number of books owned: 0
Location: Austin, Texas, USA
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Re: Dual Cameras on Kit with Canon + CHDK

Post by vitorio » 17 Nov 2013, 23:54

We used stock USB 5V power adapters, plugged into a power strip, to trigger the cameras, instead of wiring anything custom. We'd just flip the power switch on and off.

Pull the handle down.

Image

Turn the power strip on to focus.

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Turn the power strip off to take the picture.

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Pull the handle up, turn the page, repeat.

Image

ycpdan
Posts: 22
Joined: 03 Oct 2011, 16:10
E-book readers owned: iRex / Kindle DX/ Nook
Number of books owned: 300
Country: USA

Re: Dual Cameras on Kit with Canon + CHDK

Post by ycpdan » 15 Dec 2013, 18:31

Thanks! That seems easier than soldering or hacking the ca-1
In your version are you just setting the one push or doing a delay?

I found a splitter that seems to work, but waiting for the second camera to fully test it out.

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jck57
Posts: 376
Joined: 23 Nov 2009, 15:21

Re: Dual Cameras on Kit with Canon + CHDK

Post by jck57 » 16 Dec 2013, 18:19

You could plug your power strip into a deadman style footswitch.

http://www.amazon.com/Off-Deadman-Style ... FOOTSWITCH

Crispy
Posts: 14
Joined: 24 Apr 2015, 12:13
Number of books owned: 1500
Country: UK

Re: Dual Cameras on Kit with Canon + CHDK

Post by Crispy » 19 May 2015, 11:20

jck57 wrote:You could plug your power strip into a deadman style footswitch.

http://www.amazon.com/Off-Deadman-Style ... FOOTSWITCH
I've been looking for a way to trigger two cameras using CHDK; this looks like a nice and simple solution!

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