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Re: More on wifi range - Pi PICO W Oil level sensor

From "Carlos E.R." <robin_listas@es.invalid>
Newsgroups comp.sys.raspberry-pi, comp.os.linux.misc
Subject Re: More on wifi range - Pi PICO W Oil level sensor
Date 2025-12-13 13:57 +0100
Message-ID <6e401mxo86.ln2@Telcontar.valinor> (permalink)
References <10h8unl$oq21$1@dont-email.me> <u1pr0mx06p.ln2@Telcontar.valinor> <10hgrgu$2r3rh$2@dont-email.me>

Cross-posted to 2 groups.

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On 2025-12-12 11:41, The Natural Philosopher wrote:
> On 11/12/2025 21:18, Carlos E.R. wrote:
>> On 2025-12-09 11:47, The Natural Philosopher wrote:
>>> First of all thanks to all those who responded on my first efforts to 
>>> put a battery power Pi Pico W outside and have it phone home.
>>>
>>> Having eliminated temperature and supply voltage as issues, I delved 
>>> into wifi and router logs, and it was clear that it was sometimes 
>>> getting a DHCP lease and even occasionally opening a TCP/IP 
>>> connections and sending data. And might be dependent on where I 
>>> parked the car and the weather.
>>>
>>> I tried putting a tin tray behind the router and that made it worse.
>>>
>>> Now the layout was that a ground floor router through the window and 
>>> the garage was not very good at about 30m range.
>>>
>>> Then I remembered I had put an Ethernet port in an upstairs bedroom 
>>> by the window in case I wanted to use it as an office.
>>>
>>> It was further away - 35m or so - but much less cluttered path. It 
>>> just had to go through a corner of the garage.
>>>
>>> Instantly the router reported about 8-10dB more signal and almost 
>>> reliable comms resulted.
>>
>> Two ideas.
>>
>> Some routers can steer the signal horizontally; the technology is 
>> called "MIMO" (https://en.wikipedia.org/wiki/MIMO). You notice because 
>> the router has multiple antenas, maybe four.
>>
>> Then you can replace the antena on the router or the remote with a 
>> directional WiFi antena. Home made with a box of Pringles. just google 
>> for "pringles wifi antenna". I made one and it actually works. But 
>> maybe they are sold, too.
>>
> I sorta tried that without huge success, In fact I am getting up to 12dB 
> variation in signal due to who knows what?
> 
> The setup is all somewhat experimental. At least  for now the software 
> is more or less stable - I have a few hanging daemons if the link goes 
> down mid message - but that is easily fixed .
> 
>> ...
>>
>>> And I knew all that trig would come in handy one day :-)
>>
>> You can calculate it numerically on a computer, by calculating the 
>> aproximate integral ;-)
>>
> Huh? it can be as exact as your measurements are.
> No 'approximations' here...
> 
>          diameter= tankDepth - offset;
>          radius = diameter * 0.5;
>          y = echoDepth - offset -radius;
>          theta = asin( y / radius);
>          x = radius * cos(theta);
>          pie= radius * radius * theta;
>          delta = x * y;
>          area= (M_PI * radius *radius)/2 - (pie + delta);
>          volume=(area/(M_PI * radius *radius ))*tankVolume;
> 
> That is about ultimately three days of work. It is redundant but I think 
> gcc can optimise out the intermediary variables that I used to make sure 
> even I could understand it.

You can aproximate the chord with a rectangle. If you divide the chord 
in two, it is two rectangles. Up to a thousand rectangles, or a million. 
The numerical result is close to the real result with a math formula. 
Kind of  Runge-Kutta.

:-D

Or ask ChatGPT for the formula. I sure don't remember it, I doubt I ever 
saw it.


> 
> 
> 
> What has been encouraging is the pinpoint accuracy of the measurements. 
> Once in a stable environment the ultrasonics are very precise. something 
> like a mm or two in a couple of metres. Probably more precise than the 
> speed of sound in air of variable pressures would justify, or indeed the 
> expansion of the oil in warmer temperatures.
> 
> LOL.
> 
> Maybe I have built the world's most complicated barometer.
> 


-- 
Cheers, Carlos.
ES🇪🇸, EU🇪🇺;

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Thread

More on wifi range - Pi PICO W Oil level sensor The Natural Philosopher <tnp@invalid.invalid> - 2025-12-09 10:47 +0000
  Re: More on wifi range - Pi PICO W Oil level sensor Andy Burns <usenet@andyburns.uk> - 2025-12-09 11:57 +0000
    Re: More on wifi range - Pi PICO W Oil level sensor The Natural Philosopher <tnp@invalid.invalid> - 2025-12-09 14:07 +0000
      Re: More on wifi range - Pi PICO W Oil level sensor Rich <rich@example.invalid> - 2025-12-09 19:14 +0000
        Re: More on wifi range - Pi PICO W Oil level sensor The Natural Philosopher <tnp@invalid.invalid> - 2025-12-09 19:17 +0000
    Re: More on wifi range - Pi PICO W Oil level sensor c186282 <c186282@nnada.net> - 2025-12-09 21:19 -0500
      Re: More on wifi range - Pi PICO W Oil level sensor Andy Burns <usenet@andyburns.uk> - 2025-12-10 05:18 +0000
        Re: More on wifi range - Pi PICO W Oil level sensor c186282 <c186282@nnada.net> - 2025-12-10 00:27 -0500
          Re: More on wifi range - Pi PICO W Oil level sensor Andy Burns <usenet@andyburns.uk> - 2025-12-10 05:38 +0000
            Re: More on wifi range - Pi PICO W Oil level sensor c186282 <c186282@nnada.net> - 2025-12-10 02:13 -0500
              Re: More on wifi range - Pi PICO W Oil level sensor Andy Burns <usenet@andyburns.uk> - 2025-12-10 08:12 +0000
              Re: More on wifi range - Pi PICO W Oil level sensor Andy Burns <usenet@andyburns.uk> - 2025-12-10 08:15 +0000
                Re: More on wifi range - Pi PICO W Oil level sensor c186282 <c186282@nnada.net> - 2025-12-10 03:56 -0500
                Re: More on wifi range - Pi PICO W Oil level sensor Andy Burns <usenet@andyburns.uk> - 2025-12-10 09:14 +0000
                Re: More on wifi range - Pi PICO W Oil level sensor The Natural Philosopher <tnp@invalid.invalid> - 2025-12-10 09:59 +0000
                Re: More on wifi range - Pi PICO W Oil level sensor c186282 <c186282@nnada.net> - 2025-12-10 05:02 -0500
                Re: More on wifi range - Pi PICO W Oil level sensor The Natural Philosopher <tnp@invalid.invalid> - 2025-12-10 10:24 +0000
                Re: More on wifi range - Pi PICO W Oil level sensor c186282 <c186282@nnada.net> - 2025-12-10 05:53 -0500
                Re: More on wifi range - Pi PICO W Oil level sensor The Natural Philosopher <tnp@invalid.invalid> - 2025-12-10 11:45 +0000
                Re: More on wifi range - Pi PICO W Oil level sensor "Carlos E.R." <robin_listas@es.invalid> - 2025-12-11 22:06 +0100
                Re: More on wifi range - Pi PICO W Oil level sensor The Natural Philosopher <tnp@invalid.invalid> - 2025-12-12 10:26 +0000
                Re: More on wifi range - Pi PICO W Oil level sensor Andy Burns <usenet@andyburns.uk> - 2025-12-12 10:39 +0000
                Re: More on wifi range - Pi PICO W Oil level sensor The Natural Philosopher <tnp@invalid.invalid> - 2025-12-12 11:14 +0000
                Re: More on wifi range - Pi PICO W Oil level sensor Andy Burns <usenet@andyburns.uk> - 2025-12-12 11:41 +0000
                Re: More on wifi range - Pi PICO W Oil level sensor The Natural Philosopher <tnp@invalid.invalid> - 2025-12-12 12:10 +0000
                Re: More on wifi range - Pi PICO W Oil level sensor c186282 <c186282@nnada.net> - 2025-12-13 01:19 -0500
                Re: More on wifi range - Pi PICO W Oil level sensor "Carlos E.R." <robin_listas@es.invalid> - 2025-12-12 12:19 +0100
                Re: More on wifi range - Pi PICO W Oil level sensor The Natural Philosopher <tnp@invalid.invalid> - 2025-12-12 12:10 +0000
                Re: More on wifi range - Pi PICO W Oil level sensor c186282 <c186282@nnada.net> - 2025-12-12 23:42 -0500
                Re: More on wifi range - Pi PICO W Oil level sensor "Carlos E.R." <robin_listas@es.invalid> - 2025-12-13 13:30 +0100
                Re: More on wifi range - Pi PICO W Oil level sensor "Carlos E.R." <robin_listas@es.invalid> - 2025-12-11 22:03 +0100
                Re: More on wifi range - Pi PICO W Oil level sensor The Natural Philosopher <tnp@invalid.invalid> - 2025-12-10 09:57 +0000
          Re: More on wifi range - Pi PICO W Oil level sensor The Natural Philosopher <tnp@invalid.invalid> - 2025-12-10 09:55 +0000
            Re: More on wifi range - Pi PICO W Oil level sensor c186282 <c186282@nnada.net> - 2025-12-10 05:36 -0500
              Re: More on wifi range - Pi PICO W Oil level sensor The Natural Philosopher <tnp@invalid.invalid> - 2025-12-10 11:33 +0000
      Re: More on wifi range - Pi PICO W Oil level sensor The Natural Philosopher <tnp@invalid.invalid> - 2025-12-10 09:47 +0000
        Re: More on wifi range - Pi PICO W Oil level sensor c186282 <c186282@nnada.net> - 2025-12-10 05:29 -0500
          Re: More on wifi range - Pi PICO W Oil level sensor The Natural Philosopher <tnp@invalid.invalid> - 2025-12-10 11:29 +0000
          Re: More on wifi range - Pi PICO W Oil level sensor Daniel James <daniel@me.invalid> - 2025-12-10 13:01 +0000
            Re: More on wifi range - Pi PICO W Oil level sensor The Natural Philosopher <tnp@invalid.invalid> - 2025-12-10 13:05 +0000
              Re: More on wifi range - Pi PICO W Oil level sensor c186282 <c186282@nnada.net> - 2025-12-10 23:19 -0500
            Re: More on wifi range - Pi PICO W Oil level sensor c186282 <c186282@nnada.net> - 2025-12-10 23:12 -0500
              Re: More on wifi range - Pi PICO W Oil level sensor The Natural Philosopher <tnp@invalid.invalid> - 2025-12-11 08:48 +0000
                Re: More on wifi range - Pi PICO W Oil level sensor c186282 <c186282@nnada.net> - 2025-12-11 04:19 -0500
                Cable chasing (Was: More on wifi range - Pi PICO W Oil level sensor) Daniel James <daniel@me.invalid> - 2025-12-11 10:15 +0000
              Inside out (Was: More on wifi range - Pi PICO W Oil level sensor) Daniel James <daniel@me.invalid> - 2025-12-11 10:23 +0000
                Re: Inside out (Was: More on wifi range - Pi PICO W Oil level sensor) Lars Poulsen <lars@beagle-ears.com> - 2025-12-11 18:16 +0000
                Re: Inside out (Was: More on wifi range - Pi PICO W Oil level sensor) John R Walliker <jrwalliker@gmail.com> - 2025-12-11 18:28 +0000
                Re: Inside out (Was: More on wifi range - Pi PICO W Oil level sensor) "Carlos E.R." <robin_listas@es.invalid> - 2025-12-11 21:59 +0100
                Re: Inside out (Was: More on wifi range - Pi PICO W Oil level sensor) The Natural Philosopher <tnp@invalid.invalid> - 2025-12-12 11:21 +0000
                Re: Inside out (Was: More on wifi range - Pi PICO W Oil level sensor) "Carlos E.R." <robin_listas@es.invalid> - 2025-12-13 13:45 +0100
                Re: Inside out (Was: More on wifi range - Pi PICO W Oil level sensor) Bob Martin <bob.martin@excite.com> - 2025-12-14 06:38 +0000
                Re: Inside out (Was: More on wifi range - Pi PICO W Oil level sensor) The Natural Philosopher <tnp@invalid.invalid> - 2025-12-15 19:19 +0000
  Re: More on wifi range - Pi PICO W Oil level sensor "Carlos E.R." <robin_listas@es.invalid> - 2025-12-11 22:18 +0100
    Re: More on wifi range - Pi PICO W Oil level sensor The Natural Philosopher <tnp@invalid.invalid> - 2025-12-12 10:41 +0000
      Re: More on wifi range - Pi PICO W Oil level sensor "Carlos E.R." <robin_listas@es.invalid> - 2025-12-13 13:57 +0100
    Re: More on wifi range - Pi PICO W Oil level sensor The Natural Philosopher <tnp@invalid.invalid> - 2025-12-12 11:28 +0000
      Re: More on wifi range - Pi PICO W Oil level sensor "Carlos E.R." <robin_listas@es.invalid> - 2025-12-13 13:56 +0100
        Re: More on wifi range - Pi PICO W Oil level sensor John R Walliker <jrwalliker@gmail.com> - 2025-12-14 19:22 +0000
    Re: More on wifi range - Pi PICO W Oil level sensor mm0fmf <none@invalid.com> - 2025-12-24 07:58 +0000
      Re: More on wifi range - Pi PICO W Oil level sensor The Natural Philosopher <tnp@invalid.invalid> - 2025-12-24 12:16 +0000
        Re: More on wifi range - Pi PICO W Oil level sensor John R Walliker <jrwalliker@gmail.com> - 2025-12-24 14:04 +0000
          Re: More on wifi range - Pi PICO W Oil level sensor The Natural Philosopher <tnp@invalid.invalid> - 2025-12-24 14:23 +0000
            Re: More on wifi range - Pi PICO W Oil level sensor "Kerr-Mudd, John" <admin@127.0.0.1> - 2025-12-24 17:00 +0000
              Re: More on wifi range - Pi PICO W Oil level sensor The Natural Philosopher <tnp@invalid.invalid> - 2025-12-24 20:07 +0000
                Re: More on wifi range - Pi PICO W Oil level sensor mm0fmf <none@invalid.com> - 2025-12-24 23:17 +0000
                Re: More on wifi range - Pi PICO W Oil level sensor The Natural Philosopher <tnp@invalid.invalid> - 2025-12-25 03:23 +0000
                Re: More on wifi range - Pi PICO W Oil level sensor rbowman <bowman@montana.com> - 2025-12-25 07:32 +0000
                Re: More on wifi range - Pi PICO W Oil level sensor c186282 <c186282@nnada.net> - 2025-12-24 21:16 -0500
            Re: More on wifi range - Pi PICO W Oil level sensor "Carlos E.R." <robin_listas@es.invalid> - 2025-12-27 21:51 +0100
              Re: More on wifi range - Pi PICO W Oil level sensor The Natural Philosopher <tnp@invalid.invalid> - 2025-12-27 23:31 +0000
                Re: More on wifi range - Pi PICO W Oil level sensor rbowman <bowman@montana.com> - 2025-12-27 23:58 +0000
          Re: More on wifi range - Pi PICO W Oil level sensor Lars Poulsen <lars@beagle-ears.com> - 2025-12-24 23:01 +0000
        Re: More on wifi range - Pi PICO W Oil level sensor rbowman <bowman@montana.com> - 2025-12-25 02:29 +0000
      Re: More on wifi range - Pi PICO W Oil level sensor Lars Poulsen <lars@beagle-ears.com> - 2025-12-24 22:53 +0000
      Re: More on wifi range - Pi PICO W Oil level sensor Robert Riches <spamtrap42@jacob21819.net> - 2025-12-25 03:25 +0000
        Re: More on wifi range - Pi PICO W Oil level sensor The Natural Philosopher <tnp@invalid.invalid> - 2025-12-25 03:34 +0000
          Re: More on wifi range - Pi PICO W Oil level sensor "Kerr-Mudd, John" <admin@127.0.0.1> - 2025-12-25 10:43 +0000
            Re: More on wifi range - Pi PICO W Oil level sensor The Natural Philosopher <tnp@invalid.invalid> - 2025-12-25 11:43 +0000
            Re: More on wifi range - Pi PICO W Oil level sensor rbowman <bowman@montana.com> - 2025-12-25 18:44 +0000

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