power-supply noise on LED PWM strip

Other Hardware General Electronics
1

Hello guys, i tried google this issue, but maybe im using wrong keywords, maybe nobody has experienced similar problem.

Case is me trying to hook up 230LEDS long led strip (cca 4m) lenght to an arduino . The strip is supposed to be an ambilight system for my tv, using boblight in pc.

Everything function-wise is working great (if interested, look at the demo video: http://www.dailymotion.com/video/x2kzjwq_boblight-codi_tech ) . It looks and works amazing.

But the moment i turn off the leds using arduino digital port, the power supply starts to produce whining noice. The same happens if i only light up like <50% of the strip , or use <70% of brightness. Over these values, the noice dissapers completely.

Used parts:
Arduino Uno (also tested with Nano)
LED Strip using WS2812B 5050 SMD LEDs / WS2811 WS2812 30 LEDs/m
Power Source MEAN WELL RS-50-5 rated at 10A - 50W

Connection diagram:
LED strip +5V to MeanWell +5V
LED strip GND to MeanWell -pin
LED strip signal to arduino digital pin 7
Arduino GND to MeanWell -pin
USB on UNO to PC (but it also does the same if usb not connected and running test patterns, but to be precise i mention this usb connection aswell)

Hope i provided enough info for you to understand the problem + enought info abount my connections.

Side note - the power source has a voltage adjust knob, if i adjust the knob the noice changes frequency.

Any help would be really apreciated!
Havea a great day , mondy

2

The problem is called "coil whine".

Unfortunately switching supplies have a habbit of doing that.

Sometimes an electrolytic capacitor over the supply helps a bit. Sometimes not.
Sometimes the only solution is to put the supply inside a soundproof enclosure.
Leo..

3

Wawa:
The problem is called "coil whine".

Unfortunately switching supplies have a habbit of doing that.

Sometimes an electrolytic capacitor over the supply helps a bit. Sometimes not.
Sometimes the only solution is to put the supply inside a soundproof enclosure.
Leo..

Thanks a lot for info, a solution then would be changing the supply for a diferent type? Any tips good-quality power source ?

I can try to use a capacitator, not expansive to try, just dunno what capacity?

Thanks a lot for your time !
mondy

4

Try 1000uF low esr.

I have two 24volt/144watt supplies running 24/7 on main LED lighting.
They also "sing" unloaded, and at certain dim settings.
I have mounted them in the suspended ceiling cavity, and now don't hear them anymore.
Leo..

5

Wawa:
Try 1000uF low esr.

I have two 24volt/144watt supplies running 24/7 on main LED lighting.
They also "sing" unloaded, and at certain dim settings.
I have mounted them in the suspended ceiling cavity, and now don't hear them anymore.
Leo..

Thx a lot again, im gonna try using the Cap and post result.

If it wont help im gonna contruct a relay control to turn the supply on/off on arduino signal :slight_smile:

6

Very sorry to report that using Panasonic CE 1000u/16VIT PAN (PN: EEU-FM1C102) had no effect whatsoever...

Any tips that would help (tho I quess its a dead-end) are welcome :slight_smile:

Thanks!
mondy