Construction of a shielded keyboard

Step 2: Cut the aluminum foil

Cut the aluminum foil for a length just a few cm bigger than the length of the printed circuit.

Lay the printed circuit on the aluminum foil, align it to the border, leaving a margin of about 6 mm.

With a fine-point permanent marker draw the contour of every hole of the plastic foil. Then draw the contour of the whole plastic foil, while keeping the foil fixed.