How to see an enemy if they breach your area.

[BeardyMan]

don't want one maimed or killed.her indoors would be mighty pissed

Aye, not something for children to be near.
But this is PSHTF, and you wouldn't stick one near your front door, would you?

If you use battery method to deliver the required charge, then you could feasibly have an "On/Off" switch located somewhere.

Butcher a PIR sensor, and you've got a motion activated one, just like a claymore (ssshhhhhhhh.....)