On Thu, 22 Oct 2020 20:11:45 +0100 Dave Liquorice wrote:

> On Thu, 22 Oct 2020 17:35:12 -0000 (UTC), Markus Robert Kessler wrote:
>
>> I start a python script via crontab every 10 minutes which reads I2C
>> data from a BME280 sensor. This script calculates the temperature,
>> relative humidity and relative air pressure and sends it to a
>> webserver.
>
> Can't help think why you start the script every 10 mins instead of
> having in a loop with a 10 minute sleep. If you want *exactly* 10
> minutes between each sample one would have to code around the (variable)
> time taken for the data sampling, processing and up load but that's not
> difficult.
>
>> To be on the safe side I make / made a reboot every night. From this
>> the questioned machine didn't return, now. I see in the log that the
>> last transmission was ok, then the reboot was started and the
>> connection was lost. So, I doubt that the machine completely broke
>> down. Most likely the SDCard gave up.
>
> So it hasn't been power cycled and/or the SD card reseated? It could
> just be a build up of corrosion in the slot connections. Almost all
> Rapsberry boot problems I've had have been down to the latter or a bad
> micro SD to SD adapater.
>
> Not sure why you think you need to reboot if it's only running a simple
> script. A Pi Zero here:
>
> pi@PiZ-StoveB:~ $ w
>  19:37:30 up 49 days, 10:24,
>
> That Pi has extra hardware attached: An ENC28J60 ethernet port, ex nokia
> LCD phone display (both on SPI buses), a rotary encoder and a PWM driven
> solid state relay (4 GPIO's). It's talking on two 1-Wire buses (2 more
> GPIO's) with eight or so devices across the two buses. Every minute it
> reads all the 1-Wire devices, updates the display, logs the data (over
> ethernet and locally), decides if the PWM drive to the SSR is correct
> for the data it gathered and adjusts as required. The display has an
> animated "heartbeat" symbol that shows the system is alive when the PWM
> is off. If the PWM is on it rotates the symbol at the appropiate speed.
> This is all under a multi threaded python script. Oh almost forgot a
> bi-color LED that flashes green as the 1-Wire buses are read or pulses
> red at rate determined by the PWM.
>
> It's also running a web server (nginx) that can produce plots of the
> logged data on demand.
>
> It's also running pi-hole.
>
> As you can see it's doing all that and been up nearly 50 days... I've
> never known it crash in use.
>
>> P.S. I'd rather prefer to use "Raspberry Zero / WLAN" only for
>> installation, since it has only Wifi and the network there is cable
>> based.
>
> Don't follow that either.  B-)  How does the WLAN help with getting an
> ethernet connection?

WLAN doesn't help at all since at that site Wifi is deactivated. So,
replacing an RPI-A with a RPI-Zero means one has to attach an eth-to-usb
module. Better use it just for installing a new SDCard and then put this
card into the RPI-A.

Well, some months ago I wrote here about lost SDCards during reboot on
RPI-Zero. Every 10 or 20 reboots the card was no longer found during
reboot and had to be put into a desktop Linux PC. Then the partitions on
the card were found instantly and the card worked again even in a RPI-
Zero. Whoever I asked -- no clue why.

So I decided to use RPI-Zero only for testing purposes and for logging
data I use RPI-A, RPI-B and RPI-3.

So, still interested in getting infos about if or not it is possible to
install a new SDCard in a different RPI and then just put it into the
mentioned RPI-A and it works?

Thanks again,
best regards,

Markus


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