Motion sensor application in modified goalkeeper robotic game

This post will show how a motion (distance) sensor can be used to control the speed of a motor and via a crank, the speed at which a goalkeeper moves. The original construction as given by Lego is as shown below (the guidance of parents or grandparents is probably needed for this post):

Original Lego Wedo Goalkeeper construct

(building instructions here)

Lego Wedo goalkeeper game construction as per Lego building instructions
with motion sensor looking different direction from goalkeeper

Look at the direction the motion sensor is looking and the direction the goalkeeper is looking. The motion sensor is looking the wrong way. So we need to modify the setup so that the motion sensor is looking the same way as the goalkeeper - at the striker (ball kicker). Below shows the photo where the sensor is looking at the same direction as the goalkeeper:

Modified Lego Wedo Goalkeeper construct