This is the 4th week, we almost finish building the robot and still working on the programming job. So far, my robot can move forward and backward as the program, it will also turnaround(move back for 2 second and then turn left) if the sensor reading is higher than 100.

Now my robot is facing two problems: first, the sensor is getting too far from the ground, it can hardly read the signal, the robot will keep moving forward and move out of the edge without stop or moving back, I need to consider to change the shape of the robot and move the sensor closer to the ground so it can read the signal better.

The other problem is that the robot moves way too slow, maybe it's just the battery running low; but I'm still considering to change another ratio of the gear wheel for the motors to make it move faster so that it won't be easily crushed by the other robot.