The plan is that instead of having an always-on device constantly monitoring a reed switch (or similar mechanism), the normal state of the device would be off...
Were I in your shoes I would first plan to use batteries
miscreants caught sooner
The miscreants only turn up every few months. One of the reasons for NOT using a battery is that (knowing my luck) the batteries would be flat the night they next strike!
But it won't be as much fun as a home made linear generator!
Build some rodent wheels (in cages) and connect small motors to them and you have rodent powered generators.
OK, got that. How do you get them out when they die?