Re: WiFi range ...

On 8/4/26 06:37, The Natural Philosopher wrote:
> 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

   Never had to monitor an "oil tank".

   But, if exposed to sun/wind/etc, your ARE gonna
   get weird figures all day.

   As said, Temp/Humidity is a ROUGH figure always.
   Never try to get TOO technical on those figures.

>>    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.

   This "science" falls apart once you pay even the
   slightest attention.

   WHAT the fuck is going on - today or this year - is
   always kind of a mystery. Butterflies and more
   butterflies .........

>>    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

   From those devices - hell YES. Even tiny shit
   would, visibly, influence the figures.

>>    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

   Really wasn't difficult at all. Close to 'fuzzy logic'.
   Easy to do with even a '51 so long as you boosted vals
   to integers.

   Did have a big tome on fuzzy logic - dumped it when
   I retired. It DOES have its practical uses though.
   Adds some crude "AI" to things with minimal CPU
   consumption.

>>    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

   PICOs seem pretty good - although the instructions
   on-line seem WAY too complicated. Pref'ed PICS back
   in the day. A little ASM mixed with 'C' and ....

   Do HAVE a PICO ... haven't yet found a use for it.
   Will eventually.

   I'm gonna still boost the Ard Uno for 'small' stuff.
   Massively supported, a lib for EVERYTHING. Cheap,
   simple, easy to program. Even has low-power libs
   that can put it to sleep between Needs - making
   solar-powered apps work good.

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

   The 18b20 ??? It IS pretty damned good - and,
   with one-wire libs, easy to deal with. Used a
   lot of them with uC's, Ards, and lower-end PIs.

   More than "good enough".

   LAST one I did, for a Pi3, monitored temps in
   the "server room". Worked great. Little client/
   server app (python) to deliver the info. The
   "server room" was an old CLOSET ... an A/C vent
   was added but it STILL kinda ran hot. Six
   'servers' in there.

> 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?

   Don't forget "How Accurate Do You REALLY Need".

   Temp/H ... always kinda "fuzzy".

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

   If you WANT ... I'd suggest the little box with two
   18b20s - one set with a "wet bulb" ... and a tiny PI
   fan that sucks air over the sensors. This is CHEAP
   and EASY - you can fab something from junk easily
   in an afternoon.

   One of those 'travel-sized' Tylenol plastic
   bottles are good for yer wet-bulb. Arid
   climate, refill once a week. Humid climates
   you might get by longer.

   Time ... start fan 30 secs early. Take readings.
   Turn off fan. 5/10/30 minutes later, repeat.

   PICs ... long back MicroChip sold a nice all-purpose
   serial programmer box. Fit anything from 12xxx to
   all the other 8/16 chips. Great. THEN they Went
   Bad ... NOW expensive "ICE" units and you have
   to buy pretty dedicated adapters for almost EVERY
   kind of chip. A horrible rip-off. USED to use a
   lot of PICs - you could even use them to emulate
   'smart' 4000 series logic chips if you didn't need
   hyper speed - CHEAPER than many 4000 series. Have
   not used them for a good decade now ... they just
   made it too expensive/complex.

   Idiots.