Issues connecting Raspberry Pi 3/4B to Einsy by GPIO when using external power  

Issues connecting Raspberry Pi 3/4B to Einsy by GPIO when using external power

Hello 3D printing friends. I'm new to the community (only about 3 prints under my belt) but am incredibly happy with the printer and constantly asking myself why I didn't jump into this sooner!

I will try to update this post as I continue to experiment but wanted to see if there was any collective knowledge out there that might help get me to a solution faster.

I am running OctoPi on a Raspberry Pi (RPi) 4B 8GB and have been attempting to connect the Pi to the Enisy via the GPIO header pins, combining the information in the official Prusa walkthrough and other sources which I've tried to link below for reference if others come across this thread.

When connecting the 4 data pins between the two boards (Pi GPIO and Enisy J19 header) and powering the Pi using a USB-C wall wart I get garbage on the serial connection and ultimately it's unable to connect in any meaningful way. In researching this issue there have been numerous suggestions regarding the quality of the dupont jumper wires between the boards picking up noise from the electronics. I've looked for better cables and into shielding the cables, even ferrite cores around the cables but haven't found any pre-made and would need to make my own. I've tried the normal twisting and braiding of the wires to try to limit noise to no avail.

The strange thing is that when connecting the power pins from the Enisy to the Pi and removing the external power adapter the garbage clears right up and I am able to make a connection between the devices no problem at all. Clearly this is not a viable solution as the power requirements on the Pi, especially with a USB camera, are larger than the Enisy board is designed to provide but seems to partially negate the theory of noise on the jumper cables. Perhaps is a crappy power supply and noise is coming from that.

I have ordered two buck converters, one I've used on another project before as well as the one linked in the PrusaPrints case I am using from the link below and that will be the next test.

If anyone has any thoughts I'd love to hear them and I'll report back as I try additional things.

Links:

• Case combining Einsy board and Pi
• Octoprint - Configuration and install (Prusa Official)
• Configuring The GPIO Serial Port On Raspbian Jessie and Stretch Including Pi 3 and 4
• Trouble connecting Pi4 to MK3s (Einsy board) via GPIO (Octoprint forum thread)
• Raspberry Pi 3/4 Einsy Rambo RPI / GPIO Connection Tutorial (Zaribo tutorial)
• Prusa Instructions Connect Raspberry Pi GPIO Directly to Ground?! (PrusaPrinters forum, good connection diagram)