Re: Wireless temperature & humidity measurement
zithro <slack@rabbit.lu> wrote:
> On 14 Jul 2023 10:53, Joe wrote:
> > On Fri, 14 Jul 2023 09:27:12 +0200
> > Bruno Kleinert <fuddl@debian.org> wrote:
> >
> >> Hello,
> >>
> >> I'm looking for a wireless way to measure temperature and humidity
> >> indoor with hardware off the shelf and software included in Debian
> >> 12 bookworm.
> >>
> >> Sensors --> Radio --> Receiver --> Any typical PC interface, e.g.,
> >> USB, Ethernet.
> >>
> >> I don't need a visual interface, but plan to process measured
> >> values in shell scripts.
> >>
> >> Do you have any hardware recommendations and can you share
> >> experience?
>
> I use DS18B20 chips (1-wire protocol, nice for long distances
> cabling) and some BME280s or MPL3115A2, plugged on Raspberry Pies.
> The DS18B20 can be directly manipulated via sysfs, while the BMEs and
> the MPL3115A2 need a software library to interpret the sensors output
> (I use Adafruit's one, in python).
>
> A cron script records the values in a CSV, which I've linked in the
> apache folder so remote hosts can access the data file (trying to
> display a graph from 5 sensors values on a full year time period is a
> no go on a Raspi B v3).
> I've also created 2 webpages, one to quickly display the last X
> values (tail -n X), one to display a pretty graph, depending on some
> web form parameters (source host, from day X to Y, last week, etc).
> I'm using jpgraph, a PHP graph lib (free for personal use), to
> display nice curves.
> If you're not a web dev, you could also use OoO Calc or Excel to
> build the graphs from the CSV files.
>
> As you want wireless, I'd recommend a Raspi zero as it has BT+wifi
> built-in,
FWIW, a Pi Zero DOESN'T have WIFI & BT. You need a Pi Zero W for that.
I have one as another source to my OEM emonBase and it works well. I
use an Si7021 sensor although I do have some BME680 as well. It all
depends how comfortable you are playing with hardware and fiddling with
software. The emon boxes I suggested earlier are more plug and play.
> a clock (kind of), an IP stack, a webserver, etc.
> Of course an Arduino is simpler, but requires a bit more work (and
> maybe money) : no built-in storage, no built-in comms, no date/time.
> But ok, you don't need local storage or a clock/time if only sending
> values to another host, the remote host can set the time before
> recording. Although if you operate on batteries, an Arduino would be
> the best choice, as it requires a lot less energy.
>
> Another choice could be a Raspberry Pi Pico, but that's closest to an
> Arduino than to a Raspi (ie. no OS). But if I'm not mistaken, the
> advantage of the Pico is that it has built-in BT+wifi (I've not
> tested it, only read about it).
>
> In all cases, you could also turn the wireless chip(s) off till not
> sending data, or even go to (deep) sleep mode between polls (IIRC
> Arduino/Pico only).
>
> > and a bit of PHP to make a 7-day graph web page of T and H. Boot
> > script to set up the serial port and initiate logging on reboot.
>
> Joe, out of curiosity, what are you using to display the graphs ?
> If you didn't read above, I'm using jpgraph, a PHP lib.
>
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