Soft Button

Stuff you need:

aluminium foil
your hands
stripping pliers
isolated copper wire
hacked keyboard
tape

Those are the minimum requirements. When you want to make your soft button fancy , you can go all out!

Strip the copper wire , and rip two pieces of aluminium foil from the roll.

With a piece of tape , tape the copper wire on the aluminium foil. What I did here is fold the foil around the wire.
leave one end of the wire sticking out.

Take the hacked keyboard and connect the two wires to the hacked keyboard. One should go to "Ground" and the other one can go where ever you want!

When the two pieces of aluminium foil touch each other , you should be able to type a letter.

TADA! you have made a soft button!