I'm trying to find solutions for the security of an outdoor area (2km long and 1km wide). We want to detect any breach through the borders of the area, if someone sneaks in and/or someone goes out.
What I'm trying to achieve is to have the least detection nodes possible on the borders that use solar power packs to take their juice from. Let's assume that we can have 5-10 nodes in 2km length (max of 1 node each 200m) and 5 nodes in 1km width of the area. We'll have a gateway that receives the data from these end devices once motion is detected through RF (and that's not a problem). These motion sensors should be able to detect movement up to 200m away (until the next node), only detect human movements (not pets, cars, etc.), work with arduino or RPi and don't be in need of too much power.
I've done some research already, but I thought maybe someone could introduce me to an specific sensor or solution.