I've been playing around with measuring the voltage in an automotive environment. I've tried several ways but I've blown up a few A/D inputs on the arduino....
So here's my latest shot:
Any comments? Precision is not essential; I am looking at fairly gross differences in voltages. I am more concerned about protecting the inputs on the arduino without using an op-amp to isolate it.
(I'm planning to use Schottky diodes; I think that's the right symbol. The web cad I used doesn't have the symbol I am used to.)