What's wrong with the Creality Sensors they sell at Aliexpress?

it works great…… if your filament is perfectly straight. Which certainly won't be the case when you're printing with a 80% spent spool that wraps around like old telephone cords.

Too much friction between the sensor and the fliament could potentially lead to underextrusion.

Features

The Case is almost exactly the same as original, except for two:

• You can mount the sensor further away from the filament to lessen the pushing force(if you want)
• Does not constrain the filament path inside the sensor

I've also made a Mount that lets you attatch the sensor on the frame for direct drive extruders.

UPDATE: 

I've added Mount version 2!

Now the filament sensor can hang freely from a ball joint!

Requirements

• two M4 × 14/16mm flathead bolts(should come with the sensor anyway).
• get longer sensor wires, I guess.
   

Print Settings

• No supports.