[Ether]

Originally Posted by cilginbilgin

Here we have a drawing of the mechanism. Window motor will control the damper. We want damper to go down and up.

http://imageshack.us/photo/my-images...allholder.png/

Since you're using a window motor, and it looks like you've got hard stops at each extreme, you may be able to get by without a sensor if the load on the damper is known and sufficiently consistent so you can time it properly.