I am quite new to robotics and am progressing through the SparkFun Inventors Kit. However, I have gotten stuck in the last project (Motors and Robots). I am confident that my code and my wiring is correct but my motors act very strangely. When only 1 motor is being controlled by the Motor Driver, it always works as expected (for example, entering a speed and getting the motor to rotate accordingly ). However, when I have two motors (spinning both motors at listed speed for example) attached to my breadboard, most times, the motors act strange. Most times, neither motor moves, other times, they move but very slowly.
What could be the reason behind this? Could this be a current supply issue?