How many sensors can be added to pixhawk4?

can you guys tell how many sensor I can add to cover 360deg in pixhawk flight ?

1- downward facing =/ Otherwise you are currently looking at VIO or Avoidance type stuff using a companion computer. Ardupilot has out of box support for many more sensor locations than px4. (This doesn’t mean it isn’t possible- but you’ll likely be doing a lot of the work yourself)