Optical issues for use of VL53L0X ToF sensor

[Mike Wirth]

Posted on December 01, 2017 at 09:38

I would like to use the VL53L0X to determine the position of a linear position actuator (i.e., a device long and thin relative to its width).  Therefore, I would like to restrict the effective field of view of the 

VL53L0X from the 25� exclusion zone specified in the user guide to a narrower beam.

Would it work to put an opaque tube along the optical 

axis, with an absorbing coating on the inside?  Together with a small, but highly reflective target (e.g., reflective tape used for reflective signs)?  Other suggestions?

Can you provide any additional guidelines for optical configurations for the device, e.g., collimating optics?

Also, for the stated accuracy (e.g., 3% for high accuracy measurements), does that represent jitter in measurements at a fixed position (i.e., irreducible error).  Or is it an absolute error measurement, with somewhat better reproducibility?

Thanks for any info.  It's a neat device and I want to explore its usage for a variety of scenarios.

Mike

#optics #vl53l0x

[John E KVAM]

Posted on January 02, 2018 at 17:10

>>>Would it work to put an opaque tube along the optical 

axis?

I've tried this and it works - sort of. The trick is the light still bounces off the side and you get some multipath. But if you are willing to do some calibration, you can in fact get good results. Your sensor might always return 5cm, when the right answer is 4, but the results will be consistent, so you can account for the difference in software.

But clearly you are going to have to try it in your lab.

>>>Can you provide any additional guidelines for optical configurations for the device, e.g., collimating optics?

I wouldn't use any. A bit of software calibration will do it.

>>>Also, for the stated accuracy (e.g., 3% for high accuracy measurements), does that represent jitter

The 3% represents picking random targets at random distances. If you know your target and you have a fixed environment clearly you can do better. With a little work you should be able to get the error to within a few mm.

[Mike Wirth]

Posted on January 02, 2018 at 18:57

John,

Thanks.  Will give all of these suggestions a try.

Mike