Step 1: Construction.
2 large and one smaller bottlecap plastic,hot glue and gun,push activation switch,and 2 lengths of electronic wire,optional crocodile clips,and dark paint.
First cut holes in the smaller cap and a single large cap,the size of your switch,and screw/glue it in place,cut a small notch out of the lower large bottlecap,for the wires to come out of,glue the smaller top to the larger with wires now traveling through both,attach ad hot glue the lower cap on with wires placed in the notch before gluing,and your done.
Just paint it up i used dark green, let it dry and move onto the testing.
Step 2: Testing.
Now go bury it connected to a battery,and e-match airsoft device etc,a fixed safe distance away and have fun setting up small mine fields around your bunkers bases ruins so on.