How it works
Turn circuit signals into simple, testable factory controls. Each stage in the walkthrough below has a distinct practical objective; complete the current supply or control loop before expanding it.
Practical advice
Connect a storage chest to red or green wire and read item contents. Confirm the actual numeric signal before adding combinators.
Mistakes to avoid
Never assume an unrelated blueprint or another version of Factorio has identical recipes, technology unlocks or machine ratios. Use the checkpoints in this guide to diagnose your own save.
Circuits from zero to useful automation: complete walkthrough
Pick one sensor
Connect a storage chest to red or green wire and read item contents. Confirm the actual numeric signal before adding combinators.
Set one threshold
Wire an inserter or pump to the measured network and enable it only below a selected reserve. Verify the switch using a partially filled chest or tank.
Transform with combinators
Use arithmetic to process signals and decider combinators to select conditions. Label virtual signals if several controls share one area.
Avoid feedback traps
Understand whether inputs and outputs use the same network, and test set/reset behavior for latches. Factorio 2.1 extends input/output wiring controls.
Scale only after observing
Keep displays or inspection points for debugging. A circuit that seems clever but hides the real stock count is hard to maintain.