PSU Control relay won't switch off


Looks liike a few others have had this problem. How ever mine seams to be a bit different then what they have had. I am trying to use the PSU Control to turn on an off my Wanhao I3. I am using The GPIO (board) pins 2, 4, 6. I am using this 5v relay board. So with it plugged in the the Pi the red light comes on. Once I set it to GPIO (board) pin 8 the green light on the relay board turns green. Now when I use the lighting bolt at the top to try and turn the relay on or off nothing happens on the relay end but the lighting bolt with go from green to gray with nothing happening. I have tryed every thing I can think of. Last night I even did a fresh install of octo print with only installing PSU control plug in to make sure it was not a conflicting plug in. Any Ideas on what is going on. I am using the newest Pi out 3 b+.


For me it works fine. I’m using a keyestudio relay board that is plug and play to PI 3.


My setup works 2 ways. First, setting GPIO Mode to BCM, Switching Method GPIO PIN, Sensing method internal.

Did you try to turn on and off your relay using a script? This is the way I was doing before. Created a bash script, and used the plugin changing Switch Metod to System command, calling the turn-on and turn-off scripts.

Turn-on script:

gpio export 8 out
gpio -g write 8 1

Turn-off script:

gpio export 8 out
gpio -g write 8 0

This is a simple method, and you can add other commands, like turning off the usb port to turn off the printer display.


I do not think it is a problem with the hardware its self. And the reason I say that is because in the setting for Psu control under the switching setting when i set the gpio pin to 8 it turns on the relay and then when I change the number back to 0 the relay will turn off. So gpio pin set to 8 the relay turns on but the lighting bolt in the navbar does nothing. When its grayed out the relay is on when its green the relay is on. It just stays on as long as I have the gpio pin set in the settings.


I have seen a few video's on YouTube where the relay is hooked directly to the pi with out the addition of extra parts to work . What does adding in extra parts achieve?


The transistor just reduces the draw from the GPIO pin, so the relay doesn't destroy your RPi. It's a required component and already on most relay boards (it'll be a very small chip with 3 pins most likely).

My instinct says you've got the plugin misconfigured and it's switching the wrong pins. Just a guess, though, since you didn't show your settings.


Thanks for the reply. I will try to add a video later tonight to help clear up some things.



are you switching the mains power on the ATX power supply?

depending on the controller you are using, there might be other ways-

This uses RAMPS native pins to control the sense wire of the ATX controller-

I beleive that you can do the same thing by using the controller to make the connection via the relay as well between the +5VFSB & PS_ON, same way we do it with a simple toggle switch.


I am using a raspberry pi and the power supply that came with my wanhao i3


Hello did you solve the problem with relay? I have de same issue and I don´t have more ideas to tray it.


Hi R1dd1ck913,

I am wondering what you mean by "GPIO (board)", Is that the relay board ? The relay board according to the picture has VCC, GND and IN, how did you hook them up to your R-Pi ?

First thing would be to have it working on the plain command line I guess.

Jan P.


This guy solved the issue with a transistor and resistor. I can confirm this works.


Thank you. Sorry to say I'm glad some one else had the same problem as me. Thanks for the link I will order some parts and try this out.