Help setting up neopixels with rpi 4b as secondary mcu

General Discussion
1

So, I recently trying to confider neopixels with my Ender 3 pro, running Creality 4.2.7 board with pi4b as my secondary mcu.

I hooked up a single pixel to rpi to test and connected to 5V output pin. (I think my pi can run at least one pixel with that)
also i enabled PWM from config menu.

so the pi mcu is posting in mu klipper page and I also added the config lines in my printer.cfg

no error messages but the pixel is not lighting up. the pixel color selector is also showing up but nothing is happening.

I am a complete noob to this so there are many things that I could have got wrong.

maybe I am using wrong G-Code to change the output that’s why it is not lighting up.
or
my gpio is not set properly
also
maybe I have to connect the grounf to my main mcu board also as pixel is connected with only rpi.

I am saring my config file, log and some photos for reference.
please help.

printer.cfg (4.2 KB)
klippy (1).log (101.5 KB)

mcu status
mcu status1166×748 66.7 KB

2

As far as I’m aware:

  • Not every GPIO pin on the RPi can be used for Neopixels
  • Neopixels expect a level of 5V but the RPi delivers only 3V3 on the data line

There should be guides available online how to interface them.

3

I have tried different pins also regular gpio and also spi, with the data pin I have it connected to pi 5v output.

pixel to rpi connection
pixel to rpi connection1600×1200 217 KB