Servo-control on Lime

Ideas

May try to:

1. port PWM daemon from Raspberry Pi https://projects.drogon.net/software-pwm-on-the-raspberry-pi/
2. try to port ServoBlaster daemon from Pi https://github.com/threeme3/PiBits/tree/master/ServoBlaster
3. get RTAI http://www.rtai.org/ and write own PWM daemon for GPIOs (RTAI is hard realtime, but not sure if writing to GPIO will not hang the system; should try to access GPIOs directly?)