While the game currently offers lots of ability to set up large, complex production chains, the chains themselves are "dumb", i.e. each building will always produce the same item and produce as much of that item as the clockspeed allows. However, by introducing sensors and controllers these chains could be made "smart" by reacting to the state of your factory, whether that be the flow rate of a particular belt or the amount of items in a storage container.
As an example, you could be in a situation where the amount of fuel you produce is far more than the amount consumed. You have set up storage containers as buffers however they are full as well so currently your refinery would stop, however if you had a sensor on one of the storage containers you could detect it's full, convert the refinery to start producing plastic or rubber and then once the storage container sensor detects that the container is running low you would automatically switch back to producing fuel.
- Belt Flow Rate Sensor - Detects the number of items passing through the sensor per minute.
- Storage Sensor - Detects the number of item stacks in a container.
- Switch Sensor - A manual On-Off toggle for the player which can be used to trigger logic such as redirecting production to optimise a certain item.
Both sensors can be used with a controller to trigger an action and can also be seen on the map to visualise the current state of your production chain.
- Production Type Controller - Can be used to change the type of item produced by a machine.
- Clockspeed Controller - Allows building clockrate to be adjusted automatically to balance load.
- Belt Switching Controller - An extension of the Smart Splitter where instead of splitting based on the item type it will switch based on sensor values.
Controllers have the potential to be tiered, with earlier versions only allowing a single sensor as input and later ones allowing multiple sensors and more complicated logic.