External Trigger

trisha-2 · ‎2025-07-29

Dear altruist, I need urgent help. Can I apply hardware-based external triggering in the VL53L8CX sensor by STM32 Nucleo F401RE? Will the sensor work for external triggering? Thank you

John_Kvam · ‎2026-02-11

Once a topic is marked 'solved', people stop looking at it, and further conversation gets lost.

Always better to start a new thread.

The ToF sensors have a filter over the input side of the device - so only the 940nm light gets in.

The sensor establishes the ambient amount by looking at the photon hit rate before the laser is turned on.

It then 'knows' the incoming signal is anything over the ambient threshold.

So the ambient is detected using the the same SPAD array AND the same filter - it's just taking a reading without the VCSEL (laser) being turned on.

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trisha-2 · ‎2026-02-22

Dear Kvam,

Thank you so much for your response and assistance. I need some more info. If I need to add the ambient with SPAD CNH, do I need to remove the DC offset? I am getting negative values for CNH_Hist_Bin. And I need to use Ambient as well.

Look forward to your response.

trisha-2 · ‎2026-02-23

Dear Kvam,

Thank you so much for your response and assistance. I need some more info. If I need to add the ambient with SPAD CNH, do I need to remove the DC offset? I am getting negative values for CNH_Hist_Bin. And I need to use Ambient as well.

Looking forward to your response.