Hi Tom,

It has been an interesting project and weeWX has provided a much nicer 
output with minimal difficulty. 

Because data is not cached on the Arduino side, loop packets contain only 
data from a single sensor. So one sensor outputs both temperature and 
humidity. Another is only pressure. windGust comes in as a pair with 
windGustDir. windSpeed and windDir arrive together in a different loop 

It would be easy enough to insert a windGust = 0 fake into every loop 
packet that does not contain real windGust data but it seems inelegant.


On Sunday, April 8, 2018 at 9:30:30 AM UTC-7, Tom Keffer wrote:
> Hello, Joseph. Sounds like an interesting project.
> You are right that the accumulator calculates and adds windGust to the 
> archive record. The accumulators can be modified or extended and I was 
> going to show you how, but quickly got stuck. I need one more bit of 
> information: it sounds like windGust is included in the LOOP data. Is it in 
> every packet? Or, just when a new gust has been achieved? Or, what?
> -tk
> On Sat, Apr 7, 2018 at 10:47 PM, Joseph W <jwell...@gmail.com 
> <javascript:>> wrote:
>> I have been working on a weather station built around an Arduino and a 
>> CHIP. (CHIP is a linux system on a chip from NextThingCo. It is like a 
>> Raspberry Pi only with the added fun of spending hours tracking locale 
>> errors.) This hardware and driver provide only loop records. 
>> I would like to follow NWS guidance on the definition of a gust, 10 knots 
>> between peaks and lulls. My hardware follows this and only outputs gust 
>> data when this criteria is met. weeWX responded by taking the max of 
>> windspeed and recording it as windGust. I tried to get around this by 
>> recording windGust = 0 in certain loop packets but this had no effect.
>> The page below suggests that for archive records windGust will be the max 
>> windGust recorded. However, my read of accum.py suggests that windGust data 
>> is ignored completely by default and windGust is simply the max of 
>> windSpeed. (It is definitely possible I misunderstood it. add_wind_value 
>> and extract_wind seem to be the relevant functions.)
>> https://github.com/weewx/weewx/wiki/windgust
>> Is there an easer way to change this behavior so that windGust archival 
>> records are taken only from windGust loop data? 
>> Right now I am looking at subclassing Accum which requires subclassing 
>> engine.StdArchive and manager.DaySummaryManager. 
>> Accum seems to have the ability to pull preferences from weewx.conf, 
>> under [Accumulator], but I am not certain what to change to obtain the 
>> desired outcome.
>> Thank you!

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