I'm trying to find a suitable trigger for taking some MTB self portraits, I'm sure I saw an article a while back showing 2 units that could be placed either side of the trail with a beam that when broken triggered the camera. I can't remember what they were called and a Google search has been pretty fruitless, just coming up with flash triggers and wireless remotes.
Any other clever ideas for action self portraits?
Camera is a Canon 550D if that matters, I know I can do a countdown timer followed by a burst of shots, but looking for something that's a little bit less pot luck...
Apologies if this has been covered before, as I don't know the name of what I'm looking for it's hard to forum search!