Cromarty
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Software Monitoring of Supply Voltage and CPU Temperature

Tue Jan 22, 2013 1:43 pm

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?
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daveake
Posts: 198
Joined: Thu Jul 12, 2012 12:07 am

Re: Software Monitoring of Supply Voltage and CPU Temperatur

Tue Jan 22, 2013 2:04 pm

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
Posts: 10
Joined: Fri Oct 26, 2012 3:29 pm

Re: Software Monitoring of Supply Voltage and CPU Temperatur

Sun Jan 27, 2013 3:13 am

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
Posts: 78
Joined: Tue Sep 06, 2011 2:57 am
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Re: Software Monitoring of Supply Voltage and CPU Temperatur

Mon Jan 28, 2013 8:37 am

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
Posts: 196
Joined: Tue May 22, 2012 11:19 pm

Re: Software Monitoring of Supply Voltage and CPU Temperatur

Sun Aug 05, 2018 12:35 am

daveake wrote:
Tue Jan 22, 2013 2:04 pm
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?
Raspberry Pi 3 B and B+
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NAME="Raspbian GNU/Linux"
VERSION_ID="9"
VERSION="9 (stretch)"

drgeoff
Posts: 11799
Joined: Wed Jan 25, 2012 6:39 pm

Re: Software Monitoring of Supply Voltage and CPU Temperatur

Sun Aug 05, 2018 6:05 am

Quis custodiet ipsos custodes?

HvdW
Posts: 184
Joined: Tue Jun 17, 2014 12:41 pm

Re: Software Monitoring of Supply Voltage and CPU Temperature

Thu Feb 18, 2021 11:30 am

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
Who knows knows
Who doesn't doesn't

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davidcoton
Posts: 6105
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Location: Cambridge, UK
Contact: Website

Re: Software Monitoring of Supply Voltage and CPU Temperature

Thu Feb 18, 2021 12:04 pm

HvdW wrote:
Thu Feb 18, 2021 11:30 am
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.
Location: 345th cell on the right of the 210th row of L2 cache

HvdW
Posts: 184
Joined: Tue Jun 17, 2014 12:41 pm

Re: Software Monitoring of Supply Voltage and CPU Temperature

Thu Feb 18, 2021 5:44 pm

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.
Who knows knows
Who doesn't doesn't

RedMarsBlueMoon
Posts: 254
Joined: Mon Apr 06, 2020 3:49 am

Re: Software Monitoring of Supply Voltage and CPU Temperature

Thu Feb 18, 2021 5:56 pm

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

Image

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

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davidcoton
Posts: 6105
Joined: Mon Sep 01, 2014 2:37 pm
Location: Cambridge, UK
Contact: Website

Re: Software Monitoring of Supply Voltage and CPU Temperature

Thu Feb 18, 2021 5:57 pm

HvdW wrote:
Thu Feb 18, 2021 5:44 pm
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.
Location: 345th cell on the right of the 210th row of L2 cache

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