This is a paper contact switch made with a piece of paper and aluminum foil.

You will need a piece of Aluminum foil, a sheet of paper, stick glue, scissors. If you do not have stick glue, you can also use any sticky tape.

Cut out strip of paper. this will be a base shape of the switch. fold it in half, and trim 2-3cm. This shorter side becomes flap side of the switch. Cut thin strip of aluminum foil and trim 2 pieces. Each of the aluminum foil strip length is similar to length of half fold paper strip.

Apply glue on the aluminum strip and glue it on the base paper strip. On shorter flap side, place it on the outside and fold 2-3cm over the edge. On longer base side, place it on the inside. You can see the last 2 pictures to see how the aluminum foils is placed. If you do not have glue, you can use sticky tapes. In this case make sure that tape is not covering where the switch need to make electrical contact.

Fold the switch and place the shorter flap side up. It will contact when you press the flap.

Alternatively you can think of different switch design.