How do I read the CPu temperature with the Yocto ELK OS build please?
The usual methods like;
/opt/vc/bin/vcgencmd
&
cat /sys/class/thermal/thermal_zone0/temp
don’t work.
Would also be handy to see actual cpu frequency is, again vgencmd doesn’t work as it’s seemingly not part of this yocto build.
many thanks in advance
Paula
HI @Paula,
we will release soon this week a 0.7.1 bugfix and we’ll include there the packages for vcgencmd
.
If you want to try a preview in the meanwhile, get the attached .tar.gz here, unpack it on the board and run the install.sh
script as root to install it on your Pi.
For the CPU speed, it was already possible to read the CPU frequency using:
cat /sys/devices/system/cpu/cpu0/cpufreq/scaling_cur_freq
but since we can’t support adaptive frequency governors with Xenomai, the output here should always be either 600 MHz or 1.5 GHz depending on how you set your CPU speed (you can easily change the value with elk_system_utils
).
Hi @Paula,
You got any luck with that? I’m using ELK OS 0.7.1 with vcgencmd
already installed, but when I run vcgencmd measure_temp
I get VCHI initialization failed
. @Stefano
Sadly not, I’ve had to stop working on that for a while.
hopefully @Stefano can help.
@Stefano, any suggestion about how to measure CPU temperature? 
HI @frederic,
sorry we are a little slower than usual these days.
sudo vcgencmd measure_temp
works fine in our RPi4s. Ah, now I see: you get that error if you don’t runvcgencmd
as sudo, simply try that.
sorry we are a little slower than usual these days.
no worries, I perfectly understand that, I just like to insist from time to time 
I feel ashamed though, that of all things I tried, I did not try simply running vcgencmd
as sudo. Works perfect.
Because I want to run this from inside my plugin so I can report temperature in my GUI easily, I added mind ALL = (ALL) NOPASSWD: ALL
at the end of /etc/sudoers
so mind
user can run sudo vcgencmd measure_temp
and is not required a password. Works great!