Attach any metal capable of conducting SPARK to a spark-sensitive explosive such as C4.

Then go nuts.

Try using WIFI. It is helpful for intersecting METL, using less parts, and circuitry.

Then HEAT or COOL the WIFI to change its connection to other WIFI(Iridium616 has an idea.)

@MirrorrorriM (View Post)

 I think the only thing non-obvious from my post is "Then go nuts." :P

Try using wifi with pscn on both sides of the circuit. Or you could use pump to set off some NITR, but that has some faults to it.like this;

                                                       METL METL PSCN

PSCN WIFI PSCN                 WIFI PSCN METL PBCN PSCN

and set the ctype of the PBCN to dest.