I have 112 switches that can be either 0 OR 5 VOLTS. I need a way to change this so I have one or two lines as serial feed to an Arduino. The Arduino can then process the info and give me an output as the which of the 112 switches are hi or Lo. Normally all switches are hi and I only need to know 1. That any are now lo and it would be great if I knew which switches had changed state. Ideas please.