Hey, thank you very much about your answers. The link was helpful to me!
Im owning a Canon 550D. Sorry for not writing this.
About the implementation idea:
Magic Lantern (the firmware on the camera) has a built in intervalometer function. Using this function with an extra for controlling the arduino. So after sending the shutterEvent, wait the seconds set for exposure plus some delay and then move the slider.
About the why question:
The Dollyshield is awesome, but it is not very cheap if you buy it as a complete thing. For the DIY-Kit you need some advanced knowledge in that stuff and equipment. If you got that done, you have no housing for the arduino and its shield, the display might be okay for setting those things up, but the camera display is much more comfortable and you get to use the D-Pad.
Im intrested in learning to program those things and thought this might me a great project.
Thanks for your great work on MagicLantern. It makes a Canon Camera so much better.
My Arduino still didn't arrive.. hopefully he comes this week.
The most burning question is, how can i send commands via USB to the Arduino in Magic Lantern?
Thank you very much for you help, i hope you understand why i like this idea.