Hi everyone, following Klipper’s official instructions, I managed to install it on a Raspberry3, and now I can control my old Ender3 PRO (with creality 4.2.7 board). Always following the instructions on the site, I managed to control the GPO2 and the GPO3 of the Raspberry, to which I connected two relays to turn ON/OFF the printer and to turn ON/OFF a LED strip.
The only thing I haven’t been able to do is turn off the printer screen completely when the printer is turned off.
The power supply probably comes from the Raspberry and therefore the screen is on, albeit all BLUE.
Is there a possibility to turn off the screen completely when the printer is turned off? I know this question isn’t primarily about Klipper, but rather about Raspberry, but I hope you can help me anyway.
Based on the information provided, my guess is that your controller board is receiving power over the USB connection to the Pi so remains powered on even when the 24V power supply is switched off. The stock Creality LCD will be powered on whenever the controller board is powered on, so to address this, you’ll need to block the +5V power pin between the Pi and the controller board. One way to do this is to cut a small piece of electrical tape and cover the +5V pin in the USB-A side of the cable:
If you wanted to get really fancy, you could find the backlight resistor on the LCD PCB, reorient it to insert an N-channel MOSFET on the ground side, then connect the MOSFET gate to a spare GPIO pin on the Pi. Driving the GPIO pin high would turn on the LCD backlight and driving it low would turn off the backlight. Then you could configure that as a Klipper output pin and add appropriate commands to your macros to turn the backlight on and off with your printer’s main power.
