Noisey MOSFET LED driver problem

[DrBwts]

Hi

I'm controlling a 12v RGB LED strip from an Arduino Mega following the tutorial here >> https://learn.adafruit.com/rgb-led-strips/usage

I'm controlling with 3 pots via the Mega's ADC & everything works fine or so I thought!

In addition I have 3 servo motors that are also controlled by another 3 pots these also worked well when tested without the LED driver attached. As soon as I wire up the LED driver there is a crazy amount of noise generated that feeds back into the servo control that manifests as random jittering of the servos.

I have tried putting a number of different capacitors (basically whatever I could find in the cupboard) across the 12v - ground rails. Which do seem to filter out the higher harmonics of the noise but to get the noise (and the servo jitter) to disappear I lose servo response to their control pots.

Any tips on how to go about resolving this besides having 2 seperate systems running?

Are there any decent off the shelf drivers that dont create loads of noise?

 

[Harald Kapp]

Are there any decent off the shelf drivers that dont create loads of noise?

If it is noise from the drivers, then i doubt there are affordable less noisy circuits as the drivers consist only of a single MOSFET. One could investigate slew rate limited drivers, but before you dig into that direction: I suggest you first test whether it is really noise generated by the LED driver or an issue with the software when controlling servos and LEDs.
Disconnect the gates of the MOSFETs from the arduino but have the full software running (for servos and LEDs). If the jitter persists, the issue is not with the LED drivers.

A schematic of your circuit and a photo of the actual wiring will be helpful in further analysis. Noise issues can often be remedied by improved layout of the ground wiring.For example having separate grounds for LEDs, servos and arduino which connect only at a single point near the power supply. Here's a comprehensive article on grounding.