The Sushi Hub™ makes everything* (118 items) and uses 4 main sushi belts to circulate items to all assembling machines. This blueprint fits within a Nilaus City Block™ and has all inputs on a single side to support input from a main bus. Almost all input items are standard for a main bus, except iron gear wheels and pipes as building those on-site would not fit within a single block.
All outputs from final item assembling machines are circuit controlled by the "menu board" constant combinators located at the front of the Sushi Hub™. Change the input number of any item in the constant combinators to how many of that item you want built and the order will instantly start building if materials required are flowing through the system.
All outputs are inserted into filtered storage chests (yellow logistic chests). Controlling output this way instead of limiting number of chest slots allows robots to bring those items that are deconstructed elsewhere to be recycled back into the Sushi Hub™ either for future use or as an input to build the next tier up item. The circuits are set to always fulfill the lower tier item order before feeding the next tier up assembler. As an example if you've ordered 100 yellow belts and 200 red belts, the 100 yellow belts will be built and stored before feeding additional yellow belts to the red belt assembling machine.
The Sushi Hub™ is controlled by the "ON" constant combinator located at the front next to the menu board. Simply turn the constant combinator itself on or off to control the inflow of external items to the system. There is no need to adjust the signals. The lights will be green for on and red for off. The control leaves the loops of the sushi belts flowing to prevent backups. It is important to get a full sushi loop built and flowing before allowing input material to flow. If material is flowing and an inserter removes an item from the belt or an item is missing from the belt and then that belt is stopped for any reason, items will collapse together to fill those empty spaces. This will cause stuttering of the sushi loop as the main sorter tries to spread the items back out, but if the backup is too large it can deadlock an entire lane/belt. If this happens simply drain the belts inside and just behind the sorter until everything is flowing smooth again.
Robots are also built in the Sushi Hub™ very slowly and are circuit controlled to insert into a roboport if available (not total) robots of each type is < 10. You can configure this by changing the circuit conditions of the inserters that are inputting to the roboport near the robot assembling machines. I usually only use the Sushi Hub™ to supply my stash of robots for my personal roboports or vehicles with grids (SPIDERTRON), but over a long period of time at default settings it will grow your robot count indefinitely if you are consistently putting all your available robots to work.
Inputs to the Sushi Hub™ only require 1/8th of a belt of the tier belt you are currently using in the system into each sorter, so for example a single full belt of Iron Plates split off a bus and then split into 4 separate belts is more than enough. The inputs are as follows and are marked with constant combinators for easy identification: