Protection for arduino on two direction dc motor?
You're trying to drive a DC motor (part 'dc motor 130') directly from logic I/O pins.
That motor draws 70 mA when idling, when 800 mA stalled (jammed or starting up).
The I/O pins have weak output high/low currents (IOH/IOL) and the voltage dropped by their output stages increases with the current drawn. The absolute maximum available is 50 mA but that's not for normal operation. This is explained in this question: 'How much current can I draw from the Arduino's pins?'.
So you will need an H-bridge or equivalent for bi-directional operation.