Difference Between A and B Message

chadrockey · ‎2023-10-16

I've seen references to various A and B or (even and odd) messages for the ToF sensors.

In my application, it turns out that every other measurement is not great, so if I throw out packets based on their message ID count, then I get perfect data but at half measurement rates. The effect I see is that the measurements oscillate between the real value and a nearby (within 6 or 10cm) value.

I think for my sensor, the packet that contains the ambient data is the better one.

Is there more documentation on what the two packets are and why the measurements would be different between the two? Is there a way to set them both to operate the same so that I don't lose half the samples?

Anne BIGOT · ‎2023-10-19

Hello

There are two different VCSEL periods that are used alternatively. This is used to avoid wraparound at long distance.
Do you need to drop half of the values at long or short distances ? What is the sensor you are using ? For some, there is an offset calibration option allowing to compensate this effect. For the VL53L3CX, it is for example : PerformOffsetPerVCSELCalibration.

Regards

Anne

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