ARduino ground problems

I was receiving some very weird noise from the arduino that would come through in my servo. Turns out to be two problems:

1) I was running ground between arduino and the breadboard - but also supplying power to the breadboard and arduino from same external source. This resulted in problems both with the servo, and in the mouse pad of my mac mini! It was basically interference from the AC power strip.

2) The software that was running the servo was causing problems, I switched libraries.

Arduino MUX

Using the MUX board with Arduino is pretty great - I'm using it to read 16 different photoresistors. AFter running power, make sure to send ground signal to the EN as well.

Then 4 digital lines go to control the MUX, and one Analog in to read it.