How to fix interferences from motors?

Other Hardware Motors, Mechanics, Power and CNC
1

Hello,

I have 4 of these DC 6V Motors in my DFRobot Pirate Platform and I had it connected to Arduino Mega and Adafruit bipolar motor shield. I've got some interferences from motors (motors acted crazy and another arduino user with the same platform have had the same problem), so I soldered 3 100nF capacitors to each motors and everything seemed fine so far. After a few days my Arduino Mega (chinesse clone) went gone and I bought Adafruit Motor Shield v2, which I've connected to my Arduino Leonardo.
Unfortunetlly I have now the same problem with motor as before - they act unpredictable, each time different. I've checked the 100nF capacitors and additionally added a choke circuit to my motor shield from this site: De-coupling (last on the page), as I was advised before. Motors and Arduino is powered separatelly.
But the problem with interferences still persist.
Does anybody know how to fix that?
Thanks in advance.

2

Maybe the problem is not interference, but motor driver/power supply problems. Tell us about the power supplies.

3

To answer that, I power Arduino by 4x1.5V batteries and in a independent circuit with choke I power motors by 6x1.5V batteries and driver is CMOS-type.
Nevertheless, it works already. I'vw replaced jagged wiring for a new one and everything seems right now.
Thanks!

4

Twisted pair for all power supply and motor leads is really good...