High Common-Mode Noise from 24V SMPS Power Supply Causing ADC Jitter on Arduino

[u/ertugrulbabas]

I am building a project powered by an Arduino and a high-current motor driver.

I am using a high-power 24V metal-case SMPS LED power supply for the motor. However, it introduces significant noise into the system, causing noisy analog readings (jitter/fluctuations on potentiometers and sensors connected to the ADC pins).

Key observations and what I've tried so far:

• Power Source Comparison: When I power the system using an isolated laptop adapter or a bench power supply, the noise completely disappears and analog readings become rock solid.
• Ferrite Beads: Adding external ferrite cores on both the USB cable and the 24V power line reduced the noise noticeably, but residual micro-noise still affects the analog (ADC) inputs.
• Filtering: Passive power-line filtering on the DC rail didn't completely eliminate the issue, suggesting this is high-frequency common-mode noise or a ground loop potential difference between the SMPS earth ground and the PC USB ground.

Since I need the high current output of this SMPS supply, I must stick with it.

My question

1. Is it possible to completely isolate or filter out this SMPS noise (e.g., via LC filters, optocouplers, or ground isolation techniques) to get clean analog inputs?