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Finished: Retropie case with on/off switch and power LED



  • The nice thing is that this is such a simple way to setup a basic power switch that you can test it by just doing the software script alone, then carefully shorting pins 5 and 6 with anything conductive to test. In other words, you don’t really need to wire up a switch to do a test.

    Actually, forget that, you just need to issue a shutdown command at the command prompt and see if your fan powers down. Simple.



  • @caver01
    I believe I know the answer but since you probably know better i thought i'd ask.

    1. After performing a shutdown from switch or emulationstation, is it safe to unplug the power adaptor?

    2. Is the shutdown enough to remove the microsd card? Or should I also unplug the adaptor before removing it?

    Thanks again for all the information, it really is schoolday today. :)



  • I suspect it drops the power too, but if not you could just hook up a transistor for a few pence and connect to another gpio..

    Example here providing automatic fan control also :)

    Just google "use a transistor to control a fan on the raspberry pi", I would post a link but the forum thinks it's spam :)



  • @coldnpale said in Finished: Retropie case with on/off switch and power LED:

    @caver01
    I believe I know the answer but since you probably know better i thought i'd ask.

    1. After performing a shutdown from switch or emulationstation, is it safe to unplug the power adaptor?

    2. Is the shutdown enough to remove the microsd card? Or should I also unplug the adaptor before removing it?

    Thanks again for all the information, it really is schoolday today. :)

    The answer is yes to both, removal of the SD card is fine as long as it's not writing to the card at the time, in this case it wont be running at a software level, it's basically like standby on your computer..



  • @jebbett
    Thanks!



  • @caver01 said in Finished: Retropie case with on/off switch and power LED:

    Actually, forget that, you just need to issue a shutdown command at the command prompt and see if your fan powers down. Simple.

    When I run sudo shutdown now from the command prompt and my Pi still shuts down but the fan still goes.

    The fan runs off pins 2 & 4 if that changes the equation at all.



  • @livefastcyyoung strange. Pins 2 and 4 are both 5v as far as I can tell. Are you sure you are not using 4 and 6 (5v and ground)? Another thought is that since you might be using 5v, you could see if the USB ports power down during a shutdown. If so, you could pull 5v from a USB port by hacking a cable and borrowing the red and black wires.



  • @caver01 I’m sorry, it’s definitely 4 and 6.

    Unfortunately, I don’t have a free USB port. :(

    Edit: is it possible in a shutdown script, to tell the Pi to kill all power for certain pins in the GPIO?



  • @livefastcyyoung said in Finished: Retropie case with on/off switch and power LED:

    Edit: is it possible in a shutdown script, to tell the Pi to kill all power for certain pins in the GPIO

    Yes, see my previous post.. but the 5v port is not a GPIO port, hence you will need to use a transistor to a GPIO for switching and link to the 5v for power..

    Thinking more on this, the 5v rail can be used to power the Pi, so makes sense that it does not lose power.. 3v however may still have a chance..



  • @jebbett
    Indeed, my 3v pin is powering off.
    I wired a LED's anode + resistor on pin 8 (3v) and cathode on pin 6 (bridged with the button's ground wire).

    Then I activated the voltage on pin 8 from EmulationStation>raspi-config>interfacing options>Serial.



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