Whether you’re fighting off the Nazis in wartime Poland or fighting off the doldrums in 21st-century America, a DIY Enigma Machine can improve matters considerably. This kit, designed using a child’s toy and an Arduino board, allows you to encode and decode messages electronically and, if you’re really ambitious, turn the tide of the war by time-travelling back to Bletchley Park in 1936 and dropping this in Turing’s lap while he naps under a stately larch.
The DIY kit requires quite a bit of soldering and electronics know-how but it looks like a blast.