Hi Nick, long time no see. The idea of the pressure sensor line is a good idea also. I dont really want to have to build a system for the gun to traverse, just cover a fixed point. that is why I was thinking of building a pressure pad switch. When a vehicle runs over it it triggers the gun. The gun will have a fixed target are. Trip the trigger Boom your dead. Thats why I want the gun to fire as many rounds as possible. 3- 5 I think would be good. That would kill most light vehicles. The heavies I'm saving for my 88 which will be a nasty suprise if they happen to get past my Pak 40.And that is RC'ed so I will be able to cover a much wider field of fire. And i have a few upgrades planned for that also.. This is the cool kind of projects I like to do. Just don't have any electronics background.