Re: WiFi range ...

On 04/08/2026 01:20, c186282 wrote:
> On 8/3/26 07:22, The Natural Philosopher wrote:
>> On 03/08/2026 05:12, c186282 wrote:
>>> kind-of EXACT humidity readings are a sort
>>>    of black art.
>>
>> The presence of a tree exuding transpired water can totally distort a 
>> reading
>> As cam a crowd of sweaty people
> 
>    Immediate environment is indeed a complicating factor !
>    Similar issues with getting accurate temperatures. Sun
>    hits a dark or concrete patch 50 yards away at a certain
>    time of day and it may send a plume of hot air at yer
>    device.
> 
My oil tank monitor regularly shows temps over 40°C in its black case 
with the sun shining on it

>    As such, most such measurements are going to just be
>    "(maybe) Good Enough".
> 
>    There are standards for professional instruments like
>    the Weather Service might install at airports and such.
>    A certain kind of housing, placement, height and such.
>    That doesn't mean the readings are 100% accurate, just
>    that they're done in a standard fashion that can more
>    or less be compared to similar installations.
> 
Yes.
The whole concept of 'global average temperature' falls apart when you 
realise most of it is interpolated from stations thousands of miles 
apart mounted in less than ideal positions.

>    I've used the olde-tyme mechanical drum recorders. It's
>    amazing how much "jitter" you could outright SEE on the
>    paper. Even opening the instrument box caused the figures
>    to jit up or down a little right before your eyes. Means
>    "accuracy" here is always a somewhat soft figure.
> 
Agreed

>    Did a one-off climate gadget for a pro greenhouse once.
>    They had data saying the crop qual would be best at a
>    very specific temperature and humidity. Spent something
>    near $400 (mid 80s dollars) on something that'd be
>    accurate enough to make them happy. It was a wet/dry
>    system (thermocouples I think but can't remember) and had
>    a little fan to suck air past the sensors. You had to
>    re-fill it with water every so many days. Used an 8051 uC
>    for recording AND actuating 'mist' squirters (just a
>    solenoid). The clients sold to the 'elite organic vegan'
>    crowd and could get top dollar for like mini tomatoes
>    and weird salad green shit I'd never eat. Pretty simple
>    programming with just a little IQ added to note the
>    RATE of humidity change and react accordingly.
> 
Nice fun bit of coding

>    Anyway, a home-grown wet/dry setup is very easy to
>    realize using ds18b20s and something even as small
>    as a Uno or Pi0. Adafruit(?) does or did sell a
>    tiny uC unit (ard compat) with a couple of A/D pins
>    and I think I2C and/or 1-wire connections. "Trinket" ?
>    Bought one long back but never got around to using it.
>    Really small and low power though.
> 
I've just used TMP36s on the PCB coupled to a PICO Ws ADC. If the Pi 
pico W is permanently powered up I subtract  four degrees to compensate 
for onboard heating

In practice it seems good to about half a degree °C

But as you say, issues can be summarised into two camps

1. How accurate is your equipment?
2. How representative is it's siting of the environment you want to monitor?

I may do something with humidity too. Experience suggest you need about 
1°C extra heating for every 10% reduction of in-house humidity.


-- 
“There are two ways to be fooled. One is to believe what isn’t true; the 
other is to refuse to believe what is true.”

—Soren Kierkegaard