Quote Originally Posted by Pete View Post
<snip> Unfortunately the feedback in the galvos that I received are optical, there are two light sensors, an LED and a piece of glued cardboard on the spindle, the position is apparently sensed by comparison of the two optical sensors and the cardboard baffle moves and changes the proportion. I can't believe that the accuracy of these is actually any better than the stock peachy galvos (although they will be faster but they do burn significant power).<snip>.
Sounds like it's possible (maybe easy even) to improve the optical feedback to the PID and thereby improving these drastically - Getting closed loop servo's on the printer, should (if the sensor works properly) guarantee repeatability of the printer.
Since you have access to these kind of galvo's,(if you still have them) would it be possible for you to take some pictures of this feedback loop? I'm very curious!

Kind regards
Martin