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?
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See also this answer for how to detect undervoltage with software.– David McCloskyCommented Jul 18, 2021 at 0:23
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3 Answers
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
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Apparently this is not true anymore, since newer boards show an thunderbolt icon when underpowered. Commented Jan 19, 2017 at 11:46
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@DmitryGrigoryev: Is the "Low Voltage Warning" no longer asserted on GPIO 35?– SeamusCommented Oct 10, 2020 at 18:17
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
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7Unfortunately these are all things inside the 3.3V regulator, meaning not so handy for detecting a gradual decline on the 5V rail.– goldilocks ♦Commented Jan 18, 2017 at 19:22
