Will Creality support Micro USB OTG 5V out, e.g. Octoprint devices.

  • I have a Ender 3 V2 with a 4.2.2 system board. I use Octoprint/Octopi on a Raspberry Pi Zero-W, which works great, even with large multi-day prints. (Don't let the nay-sayers discount the Zero)

    I was hoping that the Micro USB port would support USB OTG, so that I would not need a an additional AC power supply to run the Pi, since it only draws about 90 mA. But no, instead it has a steering diode on pin 1 of the Micro USB port, so that you can supply power to the system board/LCD display From the Micro USB, but not send power to an external device, even if the associated attached cable supports OTG. And the OTG could support current limiting to external devices.

    What is this external USB power-in feature used for anyway? If you power off the Ender 3 V2, with the Pi still powered up whacky things happen, as the Pi now supplies power to the Ender's USB port, and the LCD stays on and in a confused state. It even somehow managed to whack my SD card under these conditions, so that the next time I turned the Ender on my stored config settings were gone. There is even an aftermarket USB DC blocker available from a 3D print reseller to eliminate this goofiness. Otherwise you should always power the Pi off first, then the Ender 3. And power the Ender 3 on first, then the Pi.

    I ended up just jumpering the SMD diode D5 next to the USB port on the system board. (on my 4.2.2 board, with 4.2.7 boards the designator number could change. Ohm out pin 1 to be sure) That way the Raspberry Pi Zero starts up and is powered by the Ender 3. This eliminates the need for an additional AC power supply for the Pi, and also the necessity for power sequencing the Pi.

    Note: Don't even think of trying to run a Raspberry Pi 3/4 like this, they draw way too much power and will most likely immediately cook the regulator IC on the Ender 3 system board!!!

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