Software Monitoring of Supply Voltage and CPU Temperature

[Cromarty]

Hello,

I would like to be able to monitor the supply voltage and CPU temperature from software. Does such a thing exist and is the Raspi Model B board equipped with the necessary hardware to do this?

[daveake]

The temperature is easy enough - run this:

/opt/vc/bin/vcgencmd measure_temp

For the supply voltage AFAIK you'll have to add an A/D. That's what I do for my weather balloon tracker. In that I monitor the battery voltage but it could very easily be changed to modify the 5V rail or whatever.

Dave

[HBrydon]

Per info at http://www.elinux.org/RPI_vcgencmd_usage you can measure 4 voltages on the board with:

Code: Select all

vcgencmd measure_volts <id>

Shows voltage. id can be one of core, sdram_c, sdram_i, sdram_p, and defaults to core if not specified.

Code: Select all

root@raspberrypi:~# \
> for id in core sdram_c sdram_i sdram_p ; do \
>     echo -e "$id:\t$(vcgencmd measure_volts $id)" ; \
> done
core:   volt=1.20V
sdram_c:        volt=1.20V
sdram_i:        volt=1.20V
sdram_p:        volt=1.23V

[Coburn]

If you're looking to check the input voltage of the R-Pi and get a reading like 4.8V or 5.2V, you'll need to make your own solution. the only voltage readings built-in are CPU and RAM. Those are 1.2V, so they won't help you much.

[seanspotatobusiness]

The temperature is easy enough - run this:

/opt/vc/bin/vcgencmd measure_temp

For the supply voltage AFAIK you'll have to add an A/D. That's what I do for my weather balloon tracker. In that I monitor the battery voltage but it could very easily be changed to modify the 5V rail or whatever.

Dave

What is an A/D?

[drgeoff]

What is an A/D?

https://en.m.wikipedia.org/wiki/Analog- ... _converter

[HvdW]

Where does undervoltage kick in.
My system:

Code: Select all

vcgencmd measure_volts core
volt=0.8688V
vcgencmd measure_volts sdram_i
volt=1.1000V
vcgencmd measure_volts sdram_p
volt=1.1000V
vcgencmd measure_volts sdram_c
volt=1.1000V

RPI4 using the Raspberry Pi 15.3W USB-C Power Supply running from and powering a Samsung 840EVO 250GB ssd

[davidcoton]

Where does undervoltage kick in.
My system:

Code: Select all

vcgencmd measure_volts core
volt=0.8688V
vcgencmd measure_volts sdram_i
volt=1.1000V
vcgencmd measure_volts sdram_p
volt=1.1000V
vcgencmd measure_volts sdram_c
volt=1.1000V

RPI4 using the Raspberry Pi 15.3W USB-C Power Supply running from and powering a Samsung 840EVO 250GB ssd

Nice necro.
The low voltage warning is NOT related to any of the rails measured using vcgencmd. It kicks in when the 5V supply is below 4.63V. The 5V supply is not measured quantitatively, the warning is generated by a simple comparator.

[HvdW]

Is it possible to read this outcome somehow, somewhere?
I mean, what's the command.

Because if the software can read it in the system it must be possible to output it on screen as well.

[RedMarsBlueMoon]

This program has some kind of voltage reading but I can't vouch for how it does it,



https://www.geeks3d.com/glz/

[davidcoton]

Is it possible to read this outcome somehow, somewhere?
I mean, what's the command.

Because if the software can read it in the system it must be possible to output it on screen as well.

See vcgencmd get_throttled.