ATROPOS: Router quadcopter

Fonera is gpio bitbanged with led cpu outputs. Sensors are powered with 3.3V serial rail.

you can read a lot of pid tutorials but the best way to tune pitch and roll pid once you have the basic idea is to block the drone in pitch or roll plane and sense with your hand how drone acts when yu change pid params

Reading data and calculate pid is a time dependet task. when time is removed to improve calculations you mus read in a time fixed way. in linux you can achieve this by setting signal and alert time fixed and a kernel special schedule to allow to make the process enter in cpu. this is the best way to make uniform process. faster reads can be done without this but it will not time fixed and stabilizations will be lacking

This copter is absolutely from scratch. Those pics are from campus party Spain 2012

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