Friday January 11 2019 10:36, you wrote to All:
Change case and fan/s to a 12 or 14" variable mode one or two placed left and
front and back.
Have three in my primary system and very rarely hear any thing.
Or, for a case with a ventilation hole on top, disable the fan and fit a
cardboard tube of at least the diameter of the vent hole to use the
chimney effect for cooling. Not sure what size the tube would need to be
- 50cm @ 50mm diam - but its something you can try at zero cost and with
almost no preparation.
And never forget that ventilation at the top is useless without
corresponding openings at the bottom and vice versa. I say this this,
because I've seen that kind of silliness. Often there are openings at
the bottom, where you can't see them, but a nice, shiny, and totally
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Hi-speed fans are noisy, low-speed ones aren't.
Fit a 40mm 5V fan (eg CPC MF67761, lots of blade area, quoted 27 dBA)
that'll be pretty quiet connected directly to 5V.
Want quieter feed it via transistor from a GPIO producing a PWM
signal under software control. Can arrange for it to only run when
required and only as fast as needs be. Note if going from stopped to
moving it might need a brief full whack burst to get it going. Donno
how easy getting the CPU temp is (or isn't).
Not always. I have a tiny fan on my 3B+ and it is just audible when run
off 5V, but inaudible at 3V3. The lower voltage still gives sufficient
airflow to prevent thermal throttling on any workload I give it, where
as in a case without a fan, it quickly runs away.
On Fri, 11 Jan 2019 21:39:28 +1300, email@example.com
(Vince Coen) declaimed the following:
Pardon? A 12 INCH fan for a board that is barely 3 inches on the long
I, for one, can't spare a microwave oven for a credit card computer.
Wulfraed Dennis Lee Bieber AF6VN
Am 11.01.19 um 10:36 schrieb Bernd:
Thx, for your comments. Meanwhile I have found how to measure the temp
from the RasPi. This and the tip to use a 5V fan but connect to 3.3V
does the trick.
Thx for the ideas!
Bernd wrote, on 12-01-2019 09:20:
Readable output, not directly useful in scripts:
$ vcgencmd measure_temp
Value in millidegrees:
$ cat /sys/class/thermal/thermal_zone0/temp
Value in degrees rounded down, so 47.9 becomes 47:
$ echo $(($(cat /sys/class/thermal/thermal_zone0/temp)/1000))
Value in degrees with one decimal, using bc:
$ echo "scale=1;$(cat /sys/class/thermal/thermal_zone0/temp)/1000" | bc
The same thing without bc:
$ vcgencmd measure_temp | cut -d= -f2 | cut -d' -f1
(The decimal separator is not localised for any of these.)