One of the first things I did after I got my pole barn was to install a security system and camera system on my property. Good to know if AND WHO someone is messing with your 'toys'. I won't get into specifics, don't want to give out information about my system... but you can get all kinds of neat switches [ like the below link for large doors ], motion sensors, etc at SmartHome.. The only problem is, that if you look around on the site... they have LOTS OF NEAT STUFF. So, I warned you... [ you can spend days drueling over all the stuff they sell ]

It's good to design your system with different kinds of sensors, in case someone trys to come in thru the roof or pry a metal panel off the wall for access. No temperature problems in the winter...
Seco-Larm SM-226L Garage Door Contacts for Closed Circuits - Smarthome