We have already mentioned that these sensors either give a digital output or an analog output. But why are we so concerned about this? It's mainly because of the reason that in a typical line following we may use digital values, but in high-speed line follower robots, we opt for analog values. The greatest advantage is that there will be a smooth transition from a white surface to a black surface, and in a high-speed line following, we control the speed of the motors based on the sensor analog input, and therefore have more efficient control. For simple purposes, we go for digital output.