Beam breaking trigger

[zoom]

I'd be looking to clamp my spare camera (D300) to a section of Armco and have it triggered when a car (or motorbike) goes through a certain section of the track. Can anyone suggest anything suitable for the job? (The triggering gizmo, not the clamping one. I've got plenty of those already)

 

[chris malcolm]

A Cactus Laser Trigger from Gadget Infinity would do the job.

 

[zoom]

Thanks Chris. This looks the kind of thing I need.

 

[WelshNoob]

Magic Lantern, completely free aswell. You set it so that it would only trigger when something enters the 'focus trap' that you've set.