Checksum fail after concentration larger than 600(sometimes 1000 cannot confirm this at the moment)

Electronza / HPMA115S0

Arduino library for Honeywell HPMA115S0 particle sensor

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Checksum fail after concentration larger than 600(sometimes 1000 cannot confirm this at the moment) #3

Open joshishrey opened 3 years ago

joshishrey commented 3 years ago

Checksum fails by 2 or 4 when the concentration of aerosols get high. I have a hunch this happens when the concentration is more than the measuring limit. Is this the outcome that is expected when the concentration is too high?

jeffeb3 commented 1 year ago

I think the issue is here: https://github.com/Electronza/HPMA115S0/blob/master/src/hpma115s0.cpp#L95 The modulo is % 0xFF and the data sheet says it should be modulo 256, which is % 0x100. So if that number is greater than 255, then this modulo is wrong.