[Qbot2640]

Originally Posted by billbo911

Without a circuit diagram, I can only make suggestions that are nothing more than a guess.
That said, the first thing I would suggest is making certain that you are also tying ground from the RoboRio to the ground on the Arduino.
The next step I would do would be to put 10k ohm pull down resistors on the inputs to the Arduino. That would make sure that you have a solid ground reference, and not have the inputs to the Arduino floating.

We have the black (ground) wire from the Spike's PWM going to ground on the Arduino...is that sufficient for grounding the RoboRIO to the Arduino as suggested...and for the pulldown resistors, do I just wire the red and white each through a 10K to ground? I did have it that way on the "off-board" but eliminated the resistors when I went to the robot.