[RyanN]

Originally Posted by Ted Weisse

Don't know exactly his original plan but the circuit on the left is appears to be a simple digital on/off. The one on the right could be used with the analog input to sense two different voltages (1.67V and 3.33V) and possible options in your program.

Both are still dual state. Use the one on the left as there will be some floating voltage on the one on the right that could cause unexpected behavior of their robot.

The one on the left has a pull up resistor to keep the voltage steady, even through transition.