cvra/filter — pull request #1 by Stapelzeiger (2014-06-20 12:25:49+00:00)
Title: biquad filter sketch (DON'T MERGE)

I suggest to add a biquad filter like this.
With this we can implement lp/bp/hp filters.
It is computationally simple and there are a lot of resources on how to dimension biquad filters.
We could use this filter for the PID derivative filtering.
What do you think?