As the title says, I have a master chassis with crystal chamber motor wired to Batt+ and LED5 and an accent strip (six pixels) to Batt+, LED4, Data 1.
When the motor is set to be off, the accents behave correctly, but when the motor is set to on I get random colours flashing and banging all over the accents.
I’m guessing the cause must be electrical noise from the motor messing with the accent power/data, so I’m thinking maybe a capacitor (a la Bluetooth modules) between Batt+ and the motor FET might smooth things out?
Just thought I’d ask here before I start opening things up.
Thoughts welcome. 
A capacitor will help, but I don’t know if it will be enough to fix the problem. Motors can be very noisy. Is the motor running at full speed? Or are you using some style to control and vary the speed? Does it still flicker if the motor is running at full speed?
Yes, the motor is set to full speed (Rgb255) but I’ve also tried it at Rgb200, but it didn’t seem to make much difference. I’m guessing you’re thinking that at full speed it’s less likely to flicker than more because there wouldn’t be so much PWM shenanigans going on? (If I’ve used the term correctly).
I’ll make up a capacitor on test probes and hold it between Bett+ and the FET pad and see what happens. I’m even wondering if moving the FETs further apart might help. At the moment the LEDs are on 4 and the motor on 5, but normally I wire motors to pad 1 or 6 and I haven’t had this issue before. So I’m thinking if I physically rewire the motor to 6 on this one, maybe that might help, though it does feel like grasping at straws a bit.
That was my thought, yes.
Is your motor brushed? I think brushed motors are extra noisy.
I suspect that the best result would be by putting a capacitor as close to the motor as possible.
Not sure if swapping FETs would help, but it might. Doesn’t hurt (much) to try.
If capacitors don’t seem to help, ferrite beads might be the next thing to try.
Did you put a resistor for the motor?
Good shout Dmitry. 
Just tried adding 10 ohms. I think it improved it a bit but unfortunately hasn’t solved it. 
Hmmm… running out of ammo fast!
- Moved motor to LED6 - no change,
- Made a test probe capacitor and tried it between Motor and Batt+ and LED neg pad and Batt - no change.
- Tried Dmitry’s resistor - possible minor improvement, but not a fix.
So I guess the next stop is ferrite beads, but I don’t know too much about them. Is there a particular spec I should be looking for?
I’m guessing I just need the smallest ferrite beads I can find?
Something like this perhaps?
Yes, something like that.
Update:
Added a ferrite bead to the motor neg and what do you know - it seems to have fixed it! 
I’d have put money on it being one of those things that works in theory but doesn’t have the slightest effect in real life, but so far it does actually seem to have done the job!
Thanks as always Prof - this is a great hack to have in the toolbox! 
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