Since Pin A15 on mBot Mega is open/unused, could an additional crash sensor, say, for the front be installed, connected to Pin A15, and pick up a signal through Pin A15. How would that be block programmed since the sensing blocks only show Pins A11 and A12?
Or maybe add a fourth avoidance sensor with one placed on front, back, right side, and left side. Pull the signal through Pins A15 and A6-8?