Are they running the motor into a hard-stop? Our team does this too, but we use a timer to exit the loop after we know that it has reset to the correct position. It sounds like your motor is malfunctioning... do you have a spare? -Frank On Fri, Nov 7, 2014 at 9:59 AM, Greg Trafton <[log in to unmask]> wrote: > Hi, all. Our team has been having a great time with the missions this > year. They have been using the medium (rotary) motor for a couple of > missions, but it has been mis-behaving and I'm looking for suggestions. > Here is the behavior: > > 1) The kids put an arm on it and move it to the correct position > (backdriving the motor). > > 2) They reset the motor in code before it is used. > > 3) Sometimes (20%?) the rotary motor spins like crazy over and over > causing a failed mission and stop mission penalty. > > The only fix the kids have found for this has been to unplug and then plug > in the motor from the EV3 controller before the mission, but that takes > time and sometimes doesn't work either. > > My guess is that backdriving the motor at the beginning is the source of > the problem, but there is no way NOT to do that at least a little. > > Earlier in the season the kids tried changing ports (no luck) and wires > (no luck). We haven't changed motors because we don't have a spare. > > Has anyone else had this same problem? Any possible fixes? Bad motor or > something else? > > Thanks for any suggestions! > greg > > -- To UNSUBSCRIBE or CHANGE your settings, please visit > https://listserv.jmu.edu/archives/vadcfll-l.html and select "Join or > leave the list". > > -- VADCFLL administrative announcements are sent via > VADCFLL-ANNOUNCEMENTS-L. Visit > https://listserv.jmu.edu/archives/vadcfll-ANNOUNCEMENTS-l.html to > subscribe. > -- To UNSUBSCRIBE or CHANGE your settings, please visit https://listserv.jmu.edu/archives/vadcfll-l.html and select "Join or leave the list". -- VADCFLL administrative announcements are sent via VADCFLL-ANNOUNCEMENTS-L. Visit https://listserv.jmu.edu/archives/vadcfll-ANNOUNCEMENTS-l.html to subscribe.