Shawn Hymel over at SparkFun put together a compact Stormtrooper Voice Changer.
While there are some pre-built voice changers out there for defenders of the Empire, this solution is both compact and low cost. With only a handful of parts – a Teensy 3.2, Prop Shield Board, small speakers, a microphone, and a battery – this solution can fit entirely in a helmet.
Detailed instructions (and code) on how to up your cosplay game by sounding like a Storm (or Clone) trooper can be found on this SparkFun blog page.
May the Force be with you.