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I have a power supply connected to Raspberry Pi through digital switcher. What I want to do is disable power supply when Pi ends shutting down process. Currently it works like this: There is a script that sets one of pins to HIGH status on start and keeps it. Pin switches off with the system and power supply is disabled.

I'm not sure if this is safe, because always before the Raspberry Pi 3 has been switched off completely, the ACT LED blinks three times and then goes out, but at the current setting it does not do that because Pi loses power earlier.

Can it work this way?

Moriarty
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  • Are you aware that when you shut down the Pi pins retain their state. The only way to reset them is to power off. You may want to explore built in gpio-poweroff capability. Mind you this is an exercise in futility, unless you are running from batteries there is absolutely no point in turning power off; the circuitry will cost more than you could possibly save in power costs. – Milliways Jul 16 '17 at 10:16
  • @Milliways I try to build a portable device based on Raspberry Pi. So far the biggest problem I've encountered is switching off Raspberry Pi. I do not want to just cut off the power supply (battery), but first shut down the system and then disconnect the power. Unfortunately I cannot manually disconnect power supply when Raspberry Pi turns off. It must be done automatically. It works almost as I wanted, but I'm worried about what I described in the second paragraph of the question. – Moriarty Jul 16 '17 at 11:50
  • The LED actually blinks 10 times if you run poweroff, but gpio-poweroff provides a reliable signal when it is safe to remove power. – Milliways Jul 16 '17 at 11:59

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See https://raspberrypi.stackexchange.com/a/60226/8697 I have used this to signal poweroff (although not to actually remove power).

https://raspberrypi.stackexchange.com/a/42945/8697 is an example of practical use.

Milliways
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