VL53L0X sensor data decrease after logging start and stabilize

[YGude.1]

We are working on syringe piston measurement application using VL53L0X for required accuracy of +/- 2mm.

Overall we are getting required accuracy of +/-2mm. Sometimes we used to miss required accuracy.

While analysis we came across one behavior of sensor.

We configured sensor to High Accuracy mode with Budget Time as 900msec.

We kept object at fix position inside syringe and keep on recording data.

We observed sensor reading start at value 148-149 and stabilize to 146-147 after 2 min.

If we stop logging and start again then similar behavior observed.

Please see attached log as reference.

What are the reasons for this observation.

How we can overcome same to get 146-147 reading right from start.

[John E KVAM]

The VCSEL (laser) strength changes with temperature. That's why you see the drift.

if you do the VHV calibration you might be better.

But the calibration runs in step-sizes of 8 degrees C. So you might see some drift until the Calibration moves to the next step.

Alternately perhaps a big heat sink?

• john