VL53L1CX Measuring iPhone Distance Accurately

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Dear ST team,

Hello, I am using the VL53L1CX with the 3.2.1 library and have noticed that when measuring the distance to an iPhone, the results are not very accurate and tend to jump between several different distances. Is this caused by the iPhone’s Face ID sensor, the reflective glass surface of the iPhone, or some other reason? What can I do to improve the measurement accuracy in this scenario?

Thank you for your help.

[Zhiyuan.Han · Accepted solution]

Hi

From your issue description, I think the issue is you test setup related, can you show us your test set up with a picture. 

• iPhone's face ID will emitter IR light, or any other 940nm IR light, which will be noise to TOF. it will affect TOF accuracy, iPhone's face ID will emit IR light only when trying to unlock the screen, you can do a test, fix the iPhone position, then do the ranging measurement with TOF, this will help you to identify the issue is caused by iPhone face ID or not
•  Test target only have iPhone or something behind the iPhone? if there is something behind iPhone, there will be some energy reflect back for the target behind, which will caused return signal blur, then the measured distance could jump 

Br

Zhiyuan.Han