Why use SDM over CHDK

Everything camera related. Includes triggers, batteries, power supplies, flatbeds and sheet-feeding scanners, too.

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DDavid

Why use SDM over CHDK

Post by DDavid »

Why would we use SDM over CHDK? I understand that SDM is for handling 2
cameras but if they are being controled by a switch and not software what is the
advantage?
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daniel_reetz
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E-book readers owned: Used to have a PRS-500
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Re: Why use SDM over CHDK

Post by daniel_reetz »

Of course, you can use either one.

I strongly prefer SDM for a few reasons.

First off, the developer, David Sykes (microfunguy) is awesome. He is very responsive to feature requests and has worked with our member You1 in developing a "smart button" for our book scanners. He showed up early in the original book scanner comments to offer support to anyone. CHDK also has some very good developers, who I deeply respect, but because of the distributed nature of what they do, and the amount of work they normally have to do, it is harder to ask for stuff. Not that we do that often.

Second thing, SDM is not much like CHDK in some ways, because it is very small, very lightweight in comparison. It has no games and no other junk. I don't know if this really matters, but I like it.

So that's why I've always recommended SDM. I'm sure you can get things working with CHDK and it will be fine, too.
DDavid

Re: Why use SDM over CHDK

Post by DDavid »

Thanks Daniel. I like small too.
freemab

Re: Why use SDM over CHDK

Post by freemab »

All this makes SDM sound wonderful. But I still can't figure out how to use it.

I am still trying to wade through the documentation. The "getting started" webpage has a good deal of information, but it leaves so much ambiguous or unanswered.

To cut to the chase: I have successfully installed SDM on a 2GB SDHC card and it "works" on my camera (an A590IS). I have made an electronic trigger that works. But I cannot trigger photos that I can use. This is probably because the camera ends up in "time lapse" mode, which does not happen when I insert a SDHC that does not contain SDM, and I only figured out earlier today that that was due to the config file SDM somehow defaulted to. (The "getting started" page says nothing about that or what to do about it.)

I have spend many days getting even this far with SDM: I can't use may 32GB SDHC card because the procedure in the documentation for partitioning it doesn't work for me. I can't use the electronic trigger anyway because the photos come out either too low-resolution or merely too blurry (due to time lapse?), if the camera even triggers at all. (I haven't figured out exactly how the remote trigger is to be used -- short presses, long presses, what does it take to shoot a photo? It works sometimes but not others.) I have no idea what to do about any of this, because all the promised SDM features (like editing the config file) are hidden away in the documentation where I have yet to find them.

With far less effort I could already have made a mechanical trigger (a bicycle brake mechanism would work lovely) and I'd already be scanning books -- perhaps even with a pair of cameras that do NOT accept CHDK but which are cheaply available anywhere. My entire book-scanning effort is weeks behind what I'd expected due to all these complications.

Most of what I've actually learned has come through Google searches for information here, on the SDM yahoo group, etc. The best instruction of how to even use the SDM software on the camera is here http://www.mind2b.com/component/content ... n-software and THAT appears wrong. (Instructions 7 to 9 do not compute.)

So, is there or will there be any real support for us novice SDM users? Will somebody tell me just what the camera settings should be and what config file I need for photographing book pages, where to find it, and where the elusive config file editor might be hiding? Because if that info is on this forum or on the SDM yahoo forum, I sure haven't found it yet. In fact, a Google search (site:www.stereomaker.net "book scanner") yields NOTHING but the one animated photograph of a book scanner.

Or should I just dig out an old bicycle brake and get to work on that? Life is too short to continue this futile pursuit.
spamsickle
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Joined: 06 Jun 2009, 23:57

Re: Why use SDM over CHDK

Post by spamsickle »

I see by the other thread that you got your time lapse problem resolved.

I have never used SDM, so I can't help you with SDM questions except where SDM and CHDK overlap. I will say that I use CHDK for two things: time-lapse triggering and a custom screen display that assists me with lining up the book in the frame. I use tripods to hold my cameras, but I think the custom display might be useful for camera/scanner assemblies as well. I haven't used an external trigger (either mechanical or electronic) for more than a year now, I just have both cameras shoot a picture every six seconds. I could speed that up and get better throughput, but a nice leisurely 20 pages per minute suits me fine.

The only limitation I've run into is that the last time I checked (also more than a year ago), CHDK wouldn't work on a partition that was larger than 2 GB. That hasn't really been a problem for me in practice -- my camera takes 8 MP pictures, and I get well over 1000 shots on a 2 GB chip. I have no desire to shoot more than 2000 pages at one sitting, so for me that size is adequate.
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