Well, I can use an arduino board and was demonstrating this to a student using the arduino board however i was stumped by a question as to 'well whats the point in using a computer if you are also using a microcontroller. Isn't there some kind of redundancy?'. I think its a valid question and wanted to see if there was a way to do it. So i'm here.
Sometimes the best answer to a question is another question: Why does this PC have separate processors in the keyboard and video card? Why not just use the PC CPU?
If the student can answer this question correctly, they should understand the benefit of using a microcontroller.