This video explains how lm358 works
block diagram for the LM358 and arduino
How to make a fire or flame detector
How to make light sensor using LDR
How to make light sensor using Photo Diode
Download Labview files form the link Labview VI
This post explains the very basic LM358 OP-Am which is widely used as a comparator, this post gives overall idea of how an OP-Am works as a comparator, How it can be used to make many sensors using this principle. All the vi for the circuit can download from the above link. you can use this to make a battery tester too. Everything has explained in the video, some of the missing circuit diagram can find in the video.