Lego IR sender emitting advanced codes for 3 bit proportional steering
http://www.tau.ac.il/~stoledo/lego/AVR-ir/ http://withinspecifications.30ohm.com/2014/02/20/Fast-PWM-on-AtMega328/
Lego IR specifivation Version 1.0 http://www.philohome.com/pf/LEGO_Power_Functions_RC.pdf
Lego IR specification Verison 1.2 http://storage.technicbricks.com/Media/2010/TBs_20100304_1/LEGO%20Power%20Functions%20RC%20v120.pdf