How to use the built on Analog Comparator for comparing multiple sources.

Projects Programming
1

Hello

I'm looking into using the Arduino Uno's built in analogue comparator to help me detect a fan fail on my project and I basically need to compare two source inputs which will be in my case will by a 1.80V to 2.05V output from the fan circuit op-amp, as there are two fans there will be two voltages to compare against the 1.95V ref which is connected at AIN0 or AIN+.

I started to look at the "analogComp" library which will allow me to use the A0 to A5 pins as the AIN1 or AIN-, this library was a great start but its only allows one source to be compared against AIN0 or AIN+. I've looked in the datasheet on the Atmel 328 and I know how it basically works but I can't find any ideas or code on how to get the result I want to achieve on two sources.

Does anyone know how to achieve what I require ^^.

2

I am probably missing some important aspect of the project, but why not just put the voltages onto separate analog pins and do an analogRead(), then compare in software? That is, if you're 100% confident that voltage will not exceed 5v. You will lose resolution compared to using a lower aRef voltage, but if all you're trying to do is detect fan failure, that is probably acceptable, I think.