Comment by luma

You can get commercial Z-Wave tilt sensors for approx ~20USD a piece that will last a year or two on a single battery. With those you can mount them directly to the door (because wireless) but obviously you need a Z-Wave radio on your automation platform for that to work.

In either event, are you sure you need two sensors per door? The garage door can stop at any point, but (to my thinking) it's still only open or closed. If it's open by only a bit, open half way, mostly open, etc... it's all open in my system, meaning someone can get in or out if they want. So limit switches (or whatever) at the closed position can tell you if it's all the way closed or "not closed", which is suitable for automation purposes.