inspired by:
- http://wiki.linuxcnc.org/cgi-bin/wiki.pl?Koppi%27s_Toy
- http://linuxcnc.org/docs/html/motion/kinematics.html
- https://github.com/Chojins/LinuxCNC-Polargraph
This config has been changed for machinekit on the beaglebone black. This makes use of the PRU realtime step generation for fast stepping.
The gondola uses an Xbee radio to raise and lower the pen. A python userspace HAL component was tried first but had too much lag. The component was ported to C and run in it's own thread every 50ms.
Rather than use axis, a Python program is used to draw gcode files, log information, handle homing and gondola charging.
sta.state 1, 2 or 3 http://linuxcnc.org/docs/2.6/html/common/python-interface.html
3 is rcs error, which happens with estop
then system keeps running even after estop unpressed, because not enabled