Ahh, you've caught the arduino bug too, it seems. =)

It really is quite easy to work with, provided you know or can learn C/C++.

One point of note about using any electronic device and interfacing your camera with it:

Protect your investment!

Never hook any circuit you design up directly, unisolated, to the camera. Always use an optoisolator. The 4N28 is perfectly fine for most uses, and is cheaply found everywhere from radioshack to specialty retailers.

Some other components/sites that one might find endlessly useful w/ the arduino and a time-lapse project.

Easydriver micro-stepping stepper driver (can't get anything better, pre-built, for $15 =): http://schmalzhaus.com/EasyDriver/
L298 Compact Motor driver (for DC motors): http://www.solarbotics.com/products/k_cmd/
Gears, shafts, hubs, and DC motors: Servocity http://www.servocity.com

!c

One of the primary differences is that the easydriver only requires two arduino pins for each motor (any two pins, PWM outs not needed - one for dir and one for step), can run up to 36V, and has a manually adjustable current load. AFAIK, The mshield only lets you run two steppers for the whole board. Also note that the max voltage you can drive the steppers is the same voltage as you feed the arduino - so a max of 14v. w/ 12V steppers, you can chop them at 36V w/ the easydriver and really increase the torque.

Mind you, you can't use the stepper library w/ the easydrivers, but making the motors run a certain # of steps is as easy as:



These are one of many options - you can always, of course, make your own h-bridge for a lot less than either *grin*



Hey - look at it this way, you have LOTS of donor parts laying around *grin*

Buy a bunch of opto-isolators when you go, can never have enough =)

!c