This is a circuit network build I made for tracking the amount of items you have in a network. It was made as part of the 'Factorio Creative' series that I do on youtube.
It converts your items to a percentage, and displays the percentage as a light bar. To Use:
A) Set your settings in the constant combinator. S is the stack size of the item you are tracking. B is the number of "buckets" or slots you have of storage. (For example, S=100, B=48 if you are reading the number of iron plates (which stack at 100) in a steel chest (which has 48 slots)).
B) Hook your inventory up to the power pole with a red wire.
C) Tolerances can be adjusted through the decider combinatorics. By default Red is less than 10%, Green is greater than 50%, and everything else is yellow.