chris,

each 'rain counter decrement ignored' is a spurious value for rain.  the 
acurite console sends a value that looks like a counter wraparound.  the 
next value ends up looking like rainfall.

it is not clear whether the root cause is a bogus 5n1 unit sending the 
wrong value, the console borking a value it gets from the 5n1, or something 
else.  it could even be interference in the RF or USB comms.

this is not uncommon on low-end hardware like acurite.

there is no fix for this - the acurite firmware cannot be updated.  but 
here are some workarounds:

1) use MinMax in StdQC to eliminate large values.  unfortunately, this will 
not eliminate spurious small values, as you have seen.  and we have 
existence proof that the spurious values are not only large.

2) figure out whether the decrement is a real decrement (wraparound) or a 
spurious value.  you could set debug=1 and [Acurite].debug_raw=1 to capture 
all of the raw data.  when this happens, record the raw R1 packets.  
capture a bunch of them then see if there is a pattern to the spurious data 
that we could recognize.

3) if we see a counter decrement, retain the value of the decrement.  at 
the next rain increment, ignore the next rain increment if it is equal to 
the decrement.  this approach could work, as long as the bogus values are 
consistent, i.e., each spurious decrement is followed at some point by a 
spurious increment of the same value.  to verify that this approach would 
work, we need a list of the 'rain counter decrement' log entries, plus the 
actual values for 'rain' in the database for the same time period.

unfortunately, (or perhaps fortunately?) the acurite station i have for 
testing (a 01036) has only ever produced spurious rain values when i've 
been abusing its usb interface, and that is far from repeatable.  so any 
log/database correlations that you or anyone else seeing spurious rain on 
acurite hardware can collect would help.

if we can verify that any spurious decrement is followed by a spurious 
increment of the same size, then we can fix the driver to recognize that 
pattern.

m

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