Well, perhaps I should say "camera trigger" as the intervalometer function appears like more of a side feature for now. But being open source it is, with some programming skills, customizable.

http://triggertrap.com/

Of course, for timelapse enthusiasts who want functionality particularly suited for timelapse there's already the Little Bramper and the MX2 DollyEngine. But for some users the Triggertrap might just fit the bill. It does have two light sensors built in, so with some development (hmm, probably a lot of development) there could perhaps be potential for automated bramping.

Ive just come in here looking for maybe some reviews of the Triggertrap iPhone App and hardware... Have you any experience of it?
https://triggertrap.com/products/triggertrap-mobile/

Phil