Error: Cannot find module 'simple-debug'

i use your library, but with different methods. refer to [Ordina-JTech](https://github.com/Ordina-JTech/Ultrasonic-AR-parrot-Drone) as i want to implement an ultrasonic on Ar-drone.

i copy all of your library to ar-drone in `data/video` and run command `./node filenode.js`
but there's something error missing lib named 'simple-debug'.

do u know what's wrong with that ? and how i fix that ?