Do you mean the 5V pin on the Arduino ?
You mention powering the boards and the Arduino with DC power. What is the voltage of that supply and how is it connected to the Arduino
It would help considerably if you posted schematics of the various power solutions that you have tried. Photos of hand drawn circuits are good enough providing they show how all of the components of the project are connected and powered
If I power over my laptop USBC (laptop listed as 5v up to 3amp) -> works fine
If I program, then power via the Arduino barrel 5v Plug 5v 180mah (its a power brick from other device I no longer use)
Hense why I think maybe its amperage level
Wanted to keep it small value to start off with but digging around for better power brick now.
I will post once I have that baseline
Powering the R4 via the barrel connector needs at least 7V as the voltage passes through a voltage regulator on the board
This was correct and the fix. Input voltage I set to 5v but once I bumped to 7v on barel connector things went stable and worked as expected
I am glad that it worked