19

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?

1
  • See also this answer for how to detect undervoltage with software. Jul 18 at 0:23
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

2
  • Apparently this is not true anymore, since newer boards show an thunderbolt icon when underpowered. 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
13

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
2
  • what should be the voltage for each?
    – HelpNeeder
    Dec 20 '16 at 4:56
  • 7
    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
1

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

1
  • 1
    Can you explain how to use MoPi?
    – Kachamenus
    Oct 14 '15 at 21:51

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