Pressure Mine
An improvised anti-personnel mine: a steel can of charge under a pressure plate, with a battery and a detonator wired in. Bury it inside a claim whose cupboard lists you. Once it arms, anything heavy enough to press the plate sets it off: a survivor, one of the infected, a wheel. It can't tell friend from foe.
Crafting
Tools (not used up)
What it is for
Salvage
Taking it apart at a recycler gives: It takes 3.2 seconds.