"This is the same set up as the warning tripwire, but without the entire circuit stuff (wires, light bulb, battery, foil) and only one clothespin, and cork and some fishing wire. You put the clothespin and cork under some wight and run the fishing wire or other strong "invisible" wire through the cork, and attach the other end of the "invisible" wire to a grenade, so that when someone pulls the wire, the grenade will be forced to move along the wire tied around it's middle to the point of disturbance. remember to also run the wire trough the pin of the grenade so that when the wire is pulled, the grenade moves to the point of disturbance and detonates. works best with 3-4 second delaying grenades."

"or you could just have the grenade inside a can, remove the pin to arm, and attach it to a line so when the wire is tripped, the grenade is pulled out of the can."