December 27, 2013 at 2:42 am #21620
I had also noticed carriage stutter/shaking in some cases, which I tried to capture in the following slow-mo video: http://www.youtube.com/watch?v=YR4lfTiA9Qg. Chris, is that similar to what you saw?
Windell should know better, but my initial guess was that it might be a consequence of trying to follow the irregularities in human drawn lines since the carriage otherwise moves super smoothly when translating with the pen up.
I am also going to see if tightening the string and increasing the motor current has any effect.