On 22/06/2019 21:48, Markus Robert Kessler wrote:
> Hi druck,
>
> what you describe above (connecting the camera directly to the RPi) was
> what I did first, but that was indeed not so stable. Hence, very soon I
> switched to using an active-powered USB hub which feeds camera and RPi.
>
> It may sound strange, but for me it seems that the higher the resolution
> of the connected webcam, the more problems this will cause to RPi /
> Raspian / fswebcam.

That's not something I've found with several 8Mpix Camera V2's connected
to both 2Bs, 3Bs and Zero Ws, or some mini 5MPix ones on ZeroWs.

> In the beginning, I tried to reset the USB bus -- with no success. Then I
> added commands to my script to rmmod and insmod / modprobe the relevant
> USB-to-video kernel drivers -- that worked often, but sometimes the whole
> machine crashed (!). That was the point when I involved watchdog mechanism
> also to get the machine back again in such a case.

That sounds seriously unreliable. As Pi Zero's are cheap, I'd buy
another one to see if it behaves any better.

> To the Micro SD cards: I tried several different ones in size and
> manufacturer, but alway the same. Except Kingston -- these cards just die
> under load, but then things are clear at least...

I've found Samsung to be the best, but make sure you buy them from a
reputable source, as the market are flooded with inferior fakes.

> B.t.w., resetting the "dirty flag" is done during startup, in the hope,
> that this state may last until the machine crashes or the watchdog runs a
> hardware reset. But, it's likely that the flag will be set (again) prior
> to some crash, anyway?

The flag is set when running, and cleared by a controlled shutdown.

> Well, what I intend to try next is, what nev young recommends -- on most
> of my raspberries Bluetooth is really not needed at all.
> So, I'll switch the driver off and see.

Disabling Bluetooth will reduce the power draw slightly, which could
help if the power draw is marginal.

---druck

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