You click a button, a led lights up
You click a button on a remote control, and his value is printed in Serial
You spin the encoder, it prints the current value
You have an ultrassonic sensor, and it prints in Serial the distance captured by the sensor
It spins a motor in different powers
Simple countdown
You have an ultrassonic sensor, and as you approaches and walks away it shows in a visor the distance
You have a manipulator with 6 servo motors, and we have an ultrassonic sensor. We put a glass near the robot and it serves water