Hardware Reference
In-Depth Information
Measure Temperature
The
vcgencmd measure_temp
command reports the core temperature of the BCM2835
system-on-chip on your Raspberry Pi (in Celsius):
temp=44.4'C
Alternatively, you can get the same temperature reading by reading this value directly
from
/sys/class/thermal/thermal_zone0/temp
:
$ cat /sys/class/thermal/thermal_zone0/temp
44388
Fun with Math and Science
To convert that value to the Celsius temperature, simply divide it by 1,000.
To get Fahrenheit, multiply the Celsius temperature by 1.8 and add 32. To
get Kelvin, add 273.15 to the Celsius temperature. Is it getting hot in here,
or is it just us?
From the perspective of monitoring the Raspberry Pi hardware, this reading is prob-
ably sufficient. Since there is really no separation of the CPU/GPU (at least not from
a physical or heating perspective), this gives you an idea of how hot the board is run-
ning. That said, if you want a more detailed (or just an additional) temperature reading,
you can wire in an additional temperature sensor, as described in
Hack #37
.
Monitor Memory Split
Whether hardcoded or dynamically allocated, the
vcgencmd get_mem
command returns
the value for either the ARM CPU or the video GPU.
To see the amount of memory currently split off for the ARM CPU, run:
$ su -c 'vcgencmd get_mem arm'
arm=448M
To see the amount of memory currently split to the video GPU, run:
$ su -c 'vcgencmd get_mem gpu'
gpu=64M
Check Custom Configuration Overrides
Have you forgotten what configuration changes you have made to your Raspberry Pi?
Specifically, the ones that change settings in the firmware? While you could look
in
/boot/config.txt
, the
vcgencmd get_config
command is here to help you.
