This tutorial shows how make an Android app (with App Inventor) to control a sprite on scratch. I used the orientation sensor to move remotely the sprite and there is a lot of possibilities.
In this example, a student will use 2 different programming tools (scratch and App Inventor) but in the end he will learn that programming is not one tool but it is a way to think and to resolve problems. He will also use some feature of a mobile phone and see the difference between mobile and desktop programming

Youtube video