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Visitor II
September 15, 2026
Question

VL53L5CX crosstalk when sensor is mounted inside a movable housing

  • September 15, 2026
  • 1 reply
  • 39 views

We are testing the best position for a VL53L5CX sensor in our product. We are observing unusual behavior and are not sure how the sensor should be calibrated in this setup.

The sensor is mounted on the wall of a movable square housing and points inward. When the housing is positioned directly above a metal box, it appears that crosstalk affects the measurements in all 64 zones.

We do not have the cover glass installed yet, but we will add it to the final product.

How should the crosstalk calibration be performed in this situation?

The vl53l5cx_plugin_xtalk allows a minimum calibration target distance of 600 mm. Therefore, should we perform the calibration outside the final assembly, using the actual cover glass and a target at 600 mm? Or should the calibration be performed with the sensor in its final mechanical position?

There is another interesting observation: when the housing is positioned directly above the metal box, the crosstalk effect affects all 64 zones. However, when we raise the housing by approximately 2 cm, the crosstalk effect completely disappears, and the measurements return to the same behavior observed when the metal box is not present.

Does this indicate that we should increase the distance between the sensor/housing and the metal box? Or can the crosstalk calibration compensate for this effect while keeping the sensor in the current position?

We would appreciate any guidance on the recommended mechanical setup and calibration procedure for this configuration.

1 reply

Associate II
September 16, 2026

There are calibration flow and ranging flow before the sensor function really works.Crosstalk calibration may be required if the module is protected by a cover glass. The VL53L5CX is immune to crosstalk beyond 60 cm thanks to a histogram algorithm. However, at short distances below 60 cm, Xtalk can be larger than the actual returned signal. This gives a false target reading or makes targets appear closer than they really are. Xtalk calibration and optional function calls must be used before starting the ranging session. The get/set functions cannot be used during a ranging session, and 'on-the-fly' programming is not supported.

Please refer to UM2884 A guide to using the VL53L5CX multizone Time-of-Flight ranging sensor with a wide field of view ultra lite driver (ULD) for more detail.

According to AN5856, Usually there are 3 kinds of mechanical application configuration for sensor setup as below. Not sure which one is best fit for your design…