This week in class we learned about multiplexers and shift registers. These are very useful because they use less pins on the arduino while giving more outputs (or inputs). Dr. Hamid had us get up and used some of the students to show us all how these devices work, he had some students stand on one side of the table while others stood on the other side. He then explained how one side was the inputs while the other was the outputs and then proceeded to give us a demonstration on how multiplexers work followed by one on how shift registers work. I thought this was really cool because he explained that the multiplexer actually can only turn on one output at a time, so when you light up multiple LEDs simultaneously, the multiplexer actually goes through and turns each of them on super fast and keeps that up while the circuit runs. The shift register however, operates by making all the changes and then “latching” which then changes the outputs to what it just organized the pattern to be. They stay like this until the next “latch”.
Berry College Physical Computing 2017 