In line 4 in 1 hub with filament sensor

4-IN-1 hub + sensor
For those who don't want to change the setup but they want a hub with a filament sensor in it ( GATE )

BOM

1x 5mm ball https://s.click.aliexpress.com/e/_oBLxWQ7 
5x PC4-M6 PTFE Press Fitting  https://s.click.aliexpress.com/e/_oC9Rr5H 
1x  Microswitch 12.8 x 6.5mm  any 3d printer switch or omron  https://s.click.aliexpress.com/e/_oC7Q4Q7 (sensile) 
Here is a good price for 10m PTFE tube  https://s.click.aliexpress.com/e/_oFYV52X 

this is ideal for direct drive and MMU/MMX since it has a 2.5mm inner diameter 
 

if you print it in abs it is easy to remove the support
i have print it in the orientation that is is posted and using support. 

you can play with the orientation 
 

Check our MMX 

https://www.printables.com/model/1181017-mmx-multi-material-extruder-exclusive-beta-release