correction: the panel shoulndn't exceed 3.6V... michael.k...@gmx.at schrieb am Sonntag, 27. Dezember 2020 um 19:17:11 UTC+1:
> @Peter Quinn, thank you. I'll check the weewx part! > > Just my 2 off-topic cents: using the breadboard the voltage regulator and > the UART, powered by 5V ist a very inefficient way to run this sensor. The > simplest approach to get more time from the solar/battery combo would be to > use a 3V solar panel (which should exceed a maximum idle voltage of 3.6V) > and directly charge a LiFe battery with it. If you ensure that the ESP > powers off (deep sleep) at the ESP lower limit (datasheet says 2.5V, my > experience says ~2.3V) the LiFe lower discharge limit (2,0V) will probably > never be reached. Even with your LiPo this should be possible this way, but > you can't use all capacity, since you can't charge it over 3.6V, because > this would kill the esp. > > In brief: > - don't use such a breadboard or remove the voltage regulator and the > UARTs supply > - connect a LiFe directly to 3V3 and GND > - connect a 3V solar panel directly to 3V3 and GND > - ensure to power off the ESP when it reaches it's minimum required > voltage (maybe it's never reached), either with a protection circuit > (preferred) or the ESPs internal voltage measurement ability (not > preferred, because ESPs sometime run into a state where they aren't really > running but drawing current from the battery until the battery is flat and > damaged. > > This will extend your runtime dramatically. > > Currently I'm running my sensor on a 2500mAh LTO Battery, one sample a > minute with deep sleep in between gives me more than a week runtime. > > peterq...@gmail.com schrieb am Sonntag, 27. Dezember 2020 um 18:49:54 > UTC+1: > >> I have a secondary temperature sensor that runs on solar and a battery. >> This time a year in the northern hemisphere there's not enough sunlight to >> charge the battery sufficiently to make it through the night. I handled the >> failover to the main thermometer in my customized driver. Details here: >> https://hackaday.io/project/101680-solar-powered-wifi-temperature-sensor-for-weewx/details >> >> On Sun, Dec 27, 2020 at 7:53 AM michael.k...@gmx.at <michael.k...@gmx.at> >> wrote: >> >>> The the ESP just reads the SHT35 in a given interval and publishes the >>> reading, nothing else. No calibration necessary, the sensor is really as >>> good as advertised in the data sheet. And only the outHumidity values of >>> the station are off when humidity > 80%rh, other values are pretty much >>> accurate and even outHumidity is very accurate below 80%rh. Since I don't >>> attach too much importance on historical humidity readings, mixing up >>> different source from time to time is no big deal for me. We're talking >>> about >99% availability with the less reliable sensor. But the current >>> dewpoint and windchill are interesting for me, which both require some >>> realistic humidity values. >>> >>> "Ok, but I am not sure what ‘prefer_hardware’ has to do with things; it >>> is not the same as hardware record generation nor does ‘prefer_hardware’ >>> have anything to do with corrections. ‘prefer_hardware’ is used with the >>> StdCalculate service, corrections are used with the StdCalibrate service >>> and hardware or software record generation is used with the StdArchive >>> service." >>> >>> Thanks for pointing out. >>> >>> Greg Troxel schrieb am Sonntag, 27. Dezember 2020 um 15:01:08 UTC+1: >>> >>>> >>>> You may also want to think about calibration. Besides absolute >>>> calibration there is going to be some offset or other more complicated >>>> relationship between your two sensors. Given a "prefer precise if >>>> available" this is going to cause some flipping betweeen them. I had a >>>> little trouble following this thread, and perhaps StdCalibrate runs >>>> before the choice. >>>> >>>> But if not, and maybe you want to do this anyway, basically >>>> cross-correlated the data from both over a wide range, calculate a >>>> mapping function, and put that in the ESP8266 code so that it emits >>>> values that are consistent with your other sensor. >>>> >>>> I did this with an ESP8266 that is measuring a 12V lead-acid battery. >>>> While I can calculate expected values from the divider resistors and >>>> the >>>> data sheet, I ended up just measuring the battery and looking at the >>>> raw >>>> values and figuring out a divisor, which I stored in a calibration >>>> file. >>>> >>> -- >>> You received this message because you are subscribed to the Google >>> Groups "weewx-user" group. >>> To unsubscribe from this group and stop receiving emails from it, send >>> an email to weewx-user+...@googlegroups.com. >>> To view this discussion on the web visit >>> https://groups.google.com/d/msgid/weewx-user/1d8b9f9d-1aed-49db-8090-40ce627c1819n%40googlegroups.com >>> >>> <https://groups.google.com/d/msgid/weewx-user/1d8b9f9d-1aed-49db-8090-40ce627c1819n%40googlegroups.com?utm_medium=email&utm_source=footer> >>> . >>> >> >> >> -- >> Peter Quinn >> (415)794-2264 <(415)%20794-2264> >> > -- You received this message because you are subscribed to the Google Groups "weewx-user" group. 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