VL53L1 module with lens calibration

[Luwang]

Hi, there,

we recently fabricated one module with VL53L1CB with lens at both laser and spad sensor. 

At first, we conduct offset and crosstalk calibration and get an error code -22. With suggestion from user manual, we conduct offset and full roi calibration. And this time, we get a error code-4. We can not find the meaning of -4.

Is there anyone can help us.

Thanks

[Luwang]

[TOF_Direct] Starting XTalk calibration...
[TOF_Direct] Mode: FULL_ROI (for low crosstalk cover glass <5 kcps)
[TOF_Direct] Please place a 17% reflectance gray target at 600 mm
[TOF_Direct] Failed to configure ROI for
[12:57:43.197]收←◆XTalk calibration: -4
[TOF_Poll] XTalk calibration failed! status=-4

This feedback from tof

[Bin]

Hi:

When you first perform xtalk calibration, error code -22, which represents the following meaning:

#define VL53L1_ERROR_XTALK_EXTRACTION_NO_SAMPLE_FAIL   ((VL53L1_Error) - 22)

/*!<  Thrown when run_xtalk_extraction fn has 0 succesful samples

* when using the full array to sample the xtalk. In this case there is

* not enough information to generate new Xtalk parm info. The function

* will exit and leave the current xtalk parameters unaltered */

For your case, the general is when you added lens, no need to perform xtalk calibration. the impact of xtalk near bin0 is very small, which is why error code -22 appears.

when you conduct full roi xtalk calibration: VL53L1_XTALKCALIBRATIONMODE_FULL_ROI

error code-4, which represents the following meaning:

#define VL53L1_ERROR_INVALID_PARAMS ((VL53L1_Error) - 4 /*!< Parameter passed is invalid or out of range */

It's caused by incorrect parameter settings. You need to double check the parameter settings again.

Best Regards,

Bin FAN

[Luwang]

Hi, Bin,
Problem solved. What is the maximum distance I can reach under original firmware of VL53L1CB?

Is there any possibility that I can modify the laser duty cycle to make sure the module is class 1 eye safe even if we place lens in front of the laser?
Regards and thanks for your reply.

Lu Wang

[Bin]

Hi:

The maximum ranging distance performance is 8000mm. you can find the detailed information in Ranging performances of the VL53L1 - Application note.

In addition, as you know the VSCEL must make sure our eye safety, the setting is hard code in fw that we can't change. There are strict international standards, and any modification must undergo a series of tests and verifications before it can be used. Datasheet - VL53L1 - Time-of-Flight long-distance ranging sensor with advanced multizone and multiobject detection 

Best Regards,

Bin FAN