Friday, 28 January 2011


Well, its been over a week since I last updated the blog, but in the meantime I've not been completely ignoring the code.  I've added some improvements and will "release" an improved version with better error trapping in the next few days.  But I have encountered a problem!  Basically the backlash in the motors/gearboxes is such that moving the arm for 2 seconds in one direction is not "undone" by moving it for the same time in the opposite direction.  I'm researching at the moment to see if the error is "per command", start/stop related or directional (e.g. gravity) etc.  Once I understand the error I'll try to mitigate it (it probably won't be perfect but it has to be better than I get right now).  Anyone found interesting ways to do this?


  1. Hi

    Since there have been no posts since January, you might not be interested in this. I just throw it out there for the sake of it.

    A wxpython arm control gui with recordable movements which I wrote a few months ago. I found the best way to get around the fact that movements one way don't translate back is to use a scaling factor. Haven't looked at the code in 4 months so probably a bit rough. Never found out how to manipulate the light while moving :(


  2. There is no real way, motor is controlled by time. Actual movement depends on motor load, other motors running at the time, batter condition, angle of arm (to resolve the component of gravity) etc.

    I'm wondering about running 1 motor at a time and digitising the electrical motor noise in order to count actual motor revolutions