Problems using the VL53L0X in a 3D printed tube

[Ingo1]

I would like to use the VL53L0X in a 3D printed tube with limited space. The diameter is 6,5mm.

Since the emitter and collector have a conical characteristic, there are limitations as describes in an earlier post:

https://community.st.com/s/question/0D50X00009XkWyUSAV/optical-issues-for-use-of-vl53l0x-tof-sensor?t=1552631329121

So I printed a tube with a barrier in the middle, which separates the emitter and collector side. See uploaded Pictures. There is also one where you can see the emitting laser.

I faced the problem, that I have to use black PLA, otherwise I got a constant reading of 30-40mm (with e.g. grey material).

After using black PLA, the measurement works barely, but better:

I get a distance but with the "RangeStatus value = 2". The distance has a massive offset and when I move an object away from the sensor I found that after a specific distance (app. 30cm) the measured distance decreases.

For my use I can live with this limitations except for one problem:

When I don't place an object in front of the sensor, the measurement shows 40-50mm.

This means, that I can't tell if there is something close to the sensor or nothing.

In my application this is what I want to know. This information is also timocratical for me.

My question is now:

Why do I get a measurement of 40-50mm when the sensor is facing to infinity? Is the sensor to sensitive and finds a weak signal from some kind of reflection inside of the tube? Is there maybe a software solution?

Thanks for supporting my project

Ingo