Is it possible to detect input voltage using only software?

Question

I'm a newbie to Raspberry Pi's, but one of the things I was thinking about doing is running it off batteries (I see many people do this) - that led me to concerns about shutting down gracefully. Is there a software only solution that would allow me to detect input voltage?

See also this answer for how to detect undervoltage with software. — David McClosky, Jul 18 '21 at 00:23

Gregology · Answer 1 · 2020-04-26T18:43:48.710

12

vcgencmd will show the internal voltages for core, sdram_c, sdram_i, and sdram_p:

vcgencmd measure_volts core

The output will look something like this:

volt=1.20V

The following shell commands will display all the voltages:

for id in core sdram_c sdram_i sdram_p
do
    echo -e "$id:\t$(vcgencmd measure_volts $id)"
done

edited Apr 26 '20 at 18:43

answered Oct 11 '15 at 02:44

Gregology

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what should be the voltage for each? – HelpNeeder Dec 20 '16 at 04:56
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Unfortunately these are all things inside the 3.3V regulator, meaning not so handy for detecting a gradual decline on the 5V rail. – goldilocks Jan 18 '17 at 19:22

score 10 · Accepted Answer · answered May 15 '13 at 01:55

10

you'll need some external circuitry to do that, because afaik the raspberry does not provide the battery voltage anywhere in the system: http://raspi.tv/tag/raspberry-pi-monitoring-its-own-battery-voltage

answered May 15 '13 at 01:55

lenik

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Apparently this is not true anymore, since newer boards show an thunderbolt icon when underpowered. – Dmitry Grigoryev Jan 19 '17 at 11:46
@DmitryGrigoryev: Is the "Low Voltage Warning" no longer asserted on GPIO 35? – Seamus Oct 10 '20 at 18:17

score 1 · Answer 3 · edited Jul 13 '18 at 19:49

1

No, but MoPi is a tidy little board that provides the capability.

edited Jul 13 '18 at 19:49

Matt

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answered Mar 03 '14 at 17:06

Fred

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Can you explain how to use MoPi? – Kachamenus Oct 14 '15 at 21:51

Is it possible to detect input voltage using only software?

3 Answers3

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