ATX to GPIO: 3V3 or 5VSB or PS_ON? (PSUControl)

slvrpltd · February 7, 2022, 12:04pm

Hello,

I feel absolutely dumb or maybe I'm under a huge misapprehension. Or maybe both. So PSUControl is for controlling an ATX PSU that is commonly used in a PC, right? Or is this plugin only for these relay boards I see whenever I try to google my "problem"?

If it is not only for those relays, how do I connect my ATX PSU with my RPi? My RPi is powered by the ATX's 5VSB just fine. But how do I proceed so that my RPi can switch the ATX on and off? I assumed that I would have to connect the PS_ON pin to one of the the RPi's GPIO pins. I also read in the open issues for PSUControl about the 3V3 and PW_OK pins. Do I have to use those?

I feel so stupid as I'm searching and researching for days but I simply cannot find resources about that topic. All I see is people using the relays or connecting PS_ON to GND.

I really hope that you can help me. Thank you so much!

Edit: I got it working with the ATX's PS_ON pin on one GPIO and a 3V3 pin on another GPIO. However, I wonder if i need some kind of resistor/diode/voltage devider so that I don't fry my Pi. Can somebody elaborate please? Thank you!

Spons · February 10, 2022, 3:23pm

Can you explain how you got it to turn on? Just connect the PSU_ON to the GPIO pins?

slvrpltd · February 10, 2022, 4:49pm

As I mentioned in my edit of my initial post:

PS_ON from ATX to one RPi GPIO (switching)
3V3 from ATX to another RPi GPIO (sensing)

In PSUControl, I also checked the "Invert" for the switching pin. Keep in mind to use the BCM layout numbering of your RPi's GPIO pins.

slvrpltd · February 15, 2022, 7:56pm

i'm still not sure if i'm going to fry my pi with this setup. can anybody help please?

kantlivelong · February 15, 2022, 9:31pm

PS_ON is active LOW so use a simple NPN transistor to short PS_ON to a ground on the ATX. Put a 1-10k resistor on the base pin. Hacked this diagram up.
untitled

For sensing you can use the 3.3V rail or 12V with a voltage divider. With either be sure to put a 1-10k resistor on the GPIO side.

slvrpltd · February 15, 2022, 9:47pm

thank you for your reply! so in essence, you recommend the following wiring, right?

source: Using the Raspberry Pi to Control an ATX Power Supply : 3 Steps - Instructables

kantlivelong · February 15, 2022, 9:51pm

Seems alright though I personally used to wire 5VSB to the Pi header and not the USB.

slvrpltd · February 15, 2022, 9:59pm

in your comment Needs a wiring diagram · Issue #81 · kantlivelong/OctoPrint-PSUControl · GitHub you mention the pw_ok pin and the 3v3 pin: could you elaborate on this wiring? would the pw_ok and 3v3 pins be used in conjunction with the ps_on pin? would the transistors and resistors be necessary?