Quantity   Component name
1 × Plastic Bottle Cap
1 × Rubber O'ring with inner top and bottom walls
1 × Washer of the same or a bit bigger size of the O'ring
1 × Wood stick
1 × Pushbutton switch
1 × Protoboard
1 × Spring of the length as the depth of the plastic cap
1 × Wire, soldering iron and hot glue