cw keyer (without hardware requirements)

Yet another cw keyer? Yes!!..

Tiny and lightweight I use it with my FT-817 during QRP excursions.

But this will not require any further hardware than n. 2 M3x6 screws,
some cm of 1mm dia. silver plated (or normal) copper wire and a spring
from a retractable ball point pen.

it is composed by 3 pcs that are assembled by interlocking.

The only thing that requires a little manual skill (but if you are here it means that you have it) is the realization of the contacts using the copp