The idea is to once again program the robot by holding it up to the computer screen — but this time by analog rather than digital communications.
(I call this U-Turn Mode because of the U on the screen, but as you’ll see the robot turns left and right and goes forward too.)
When the robot’s photocell ‘eyes’ are both staring at the dark center in the middle of the U, the robot is being programmed to stop.
Holding the left eye over the bright area while the right is still in the dark will program the robot to turn left. Note the left LED lights up.
Likewise, right turn. We know it’s being programmed to turn right because the right-side LED lights up.
Holding both eyes over the bright bottom of the U programs the robot to move forward and causes both LEDs to light.
Holding the robot over the dark center for more than three seconds causes it to go into a ‘blink countdown’ for program execution (ie, it moves according to what you just programmed).
And here is the video: