Powershot A3300 AC adapter and Usb-trigger

[bimbo111]

Hi again diybookscanner.org

For my scanner i went with dual A3300. I have read a bit about this camera on the forum, but i think it needs a dedicated thread. I will post my results with the camera here and hope that others will as well. I also have some questions about chargers and triggers that owners of other cameras may be able to help with and hopefully people like me with a3300s can benefit from.

Initially after reading about different camera models i decided that i would go for the a2200 model. Also because it's the choise of 'markvdb' at diybookscanner.eu.
Buuut.... It turns out that a local supermarket currently had some discount on the a3300 series, so i went with that instead. Got two for 80€ a piece, which in my eyes is quite good since the a2200 went for 100€ (and we in Denmark have 25% VAT ).

Here you can se the one camera taking a picture of the other one :


The manual suggests that you are able to take around 300 pics/charge which in my case wont be enough. Therefore (as many of you) i need an AC-adapter. Cannon's own adapter would locally cost just as much as the camera itself so that's not an option. Online i can get this version for around 10€. Anyone tried this cheap (unofficial i suppose?) version?

I also ran into this other guy who made up his own power supply:
http://chdk.setepontos.com/index.php?topic=6089.0
Look at the bottom of the page. Anyone with experience on making AC-adapters like this from leftover materials like old phonechargers etc?

Secondly i need to examine the ways of CHDK.. I've read from several threads that Van de Kamp have the best and most affordable switches which sends an impulse to the cameras USB-port that will trigger the cameras with aid from CHDK. I think i'm gonna go with this one. Anyone have it working already with the a3300?


If anyone new haven't heard about CHDK (canon hack development kit) you can read about it here:
http://chdk.wikia.com/wiki/CHDK
I still need to do some reading about it

Hope that anyone with knowledge about the powershot a3300 will contribute to this thread! Tips not regarding powersupply / triggering are also more than welcome!

[Shaknum]

I would be very interested to know how those cameras work with this software: scan-manager -- python app for controlling tethered cameras http://www.diybookscanner.org/forum/vie ... 0&start=90. Specifically, I would love to know if live view (probably using the reyalp-ptp-live branch of chdk) and remote triggering work with it, and what the speed of transfer from camera to computer is.

Let me know if you have any questions about chdk, I did use it for a little while a few years back, and I still remember a bit about it. Also, regarding switches to trigger the camera, I'm partial to foot switches, but in any event, you will want to sort out your software side of things before you go and buy a piece of hardware like that. You may instead wish to trigger your cameras with your computer, instead of doing things in stages (taking pictures, copying from SD to the computer, interleaving the files, cropping, etc...). Finally, beware of aftermarket power sources for the camera, I have seen some real nightmares. You may be able to rig something up yourself though.

[bimbo111]

What are the advantages of using this kind of software? I don't see the problem in copying the pictures from the SD, but still - i don't have much experience yet.

[Shaknum]

What are the advantages of using this kind of software? I don't see the problem in copying the pictures from the SD, but still - i don't have much experience yet.

One advantage would be speed; instead of taking the time to upload files from each camera and interleave them before further processing, all that work can be done while you scan the book. Another really important advantage is being able to immediately see the captured page while you scan the book, I've had many instances where, for whatever reason, my camera failed to snap the picture or the camera went out of focus and I took out-of-focus pictures of 100+ pages. It is really nice to see the picture saved to the computer as you work on the book since it alleviates the quality control burden later on.

[bimbo111]

I got an idea (forgot where) about using the powersupply for an oldschool ATX motherboard. As you can see from the pinout schematics here, it is possible to draw both 3,3V and 5v. The guy who made his own supply, that i linked to in the original thread, was also able to power his camera with an excess voltage. The battery delivers 3,6v. I hope that i can power my cameras with this powersupply and not make them explode while trying However i can already imagine two problems:
[*]The 3,3v outled is simply 0,3v too low. This could be solved by using the 5v outleds coupled with some diodes.
[*]The powersupply can not deliver enough current for the high-demanding processes like moving the lense or charging the blitz.

Hope it will work

@shaknum
I see what you mean, but i think i can live with the disadvantages of using the regular sd-card method. I read somewhere that you can use 'fixed' focus - is that some kind of CHDK function?

[Shaknum]

I see what you mean, but i think i can live with the disadvantages of using the regular sd-card method. I read somewhere that you can use 'fixed' focus - is that some kind of CHDK function?

Yes you can lock the autofocus (I often find these things to be a bit finicky but you may have better luck):

set_aflockEdit
(since version 0.9.2 / changeset #681)
Lock/unlock autofocus

Usage:

Lua: set_aflock(x)

uBASIC: set_aflock x

where 1 locks the autofocus and 0 unlocks it.

It is like MF, but better in several ways, such as a) it is available on ALL cameras; b) focus is locked even after camera returns from deep display sleep (via display key cycle or print button shortcut), which is very good for timelapse, with regard to power consumption, camera shake, an actual fixed focus throughout the whole timelapse and also less stress on the mechanical parts of the camera.

Example:

press "shoot_half"
sleep 800
release "shoot_half"
set_aflock 1

[aladar]

Hi Bimbo111,

Did you get your cameras work, how are they working? Any further update on your scanner? I plan to buy a set from .eu and get the A3300 cameras, I need as high as possible resolution as I need to OCR everything I scan.

Thanks,
aladar

[bimbo111]

I passed my exams and now return my focus on the scanner

After months of waiting for my trigger from Frans van de kamp i finaly got it. I think it got stuck somewhere in the mailing system. Here's a video of two A3300 with CHDK loaded via. the firmware-method and usb-remote enabled triggering ( check this link, for how to enable usb triggering )

<<< Video!

In this clip they don't shoot at once - but i blame it on the autofocus - it is possible to get them synced. I've been thinking about using locked focus later on, but i don't like to get too much involved in the actual scripting part of CHDK. So far i managed to avoid it

[daniel_reetz]

Yeah!!! For many, this is one of the hardest things to get working...

[markvdb]

These notes I compiled may help:

https://github.com/markvdb/diybookscann ... -GNU-Linux

P.S. Feel free to improve this or other wiki pages! Editing is a simple github registration away.