Arduino whining noise USB cable

Hi

I was just playing with my arduino nano v3 clone when I noticed a feeble yet noticeable whining noise it made when I powered it with a short power only mini usb cable to a power bank. I thought my arduino was destroyed but when I connected it using my main 3 metre long mini usb cable to my laptop then the arduino works fine without any noise. So I connected that long cable to my power bank and no noise, then I tried the short cable and the noise returned.

Why does that happen? what in that short cable causes my arduino to make this noise. Loose contacts?

The noise is probably the DC-DC converter in the power bank - long cable means the power bank is further away so you can't hear it anymore. High pitch sounds are not easy to localize.

Sometimes DC-DC converter inductors happen to resonate the PCB and produce a lot of audio noise.

Sounds like that powerbank isn't good to power my arduino. Better to use inbuilt voltage regulator instead.

Hi,

noticeable whining noise it made when I powered it with a short power only mini usb cable to a power bank

So I connected that long cable to my power bank and no noise, then I tried the short cable and the noise returned.

So problem is with short- power only cable.
Throw it out, probably not a proper USB spec cable capacitance wise, so it has some resonance with the inductor in the power bank converter.

Tom.... :slight_smile:

Noobian:
Sounds like that powerbank isn't good to power my arduino. Better to use inbuilt voltage regulator instead.

Not at all, the noisy inductor thing is common and nothing to do with circuit function. Anyway you
know the thing works.

Throw it out, probably not a proper USB spec cable capacitance wise, so it has some resonance with the inductor in the power bank converter.

No, that makes zero sense. The resonance is mechanical/acoustic (all power inductors have to vibrate due to magnetostriction - whether that vibration couples to and resonates the pcb noticably is a complex function of many
things).

The cable capacitance is many orders of magnitude below the output capacitance of any converter and
cannot be relevant (unless the converter's output capacitor is missing I suppose).

Hi,

I was just playing with my arduino nano v3 clone when I noticed a feeble yet noticeable whining noise it made when I powered it with a short power only mini usb cable to a power bank.

"It" being the Nano?

Tom... :slight_smile:

TomGeorge:
Hi,"It" being the Nano?

Yes. I thought It was going to blow up eventually because the noise was like what those pressure cookers make when they just start to build up pressure.

Powerbanks are designed to charge cellphones.
It's internal DC/DC converter steps the internal LiPo battery up to 5volt for the USB connector.
The DC/DC converter turns off (sleeps) when a light load is detected (cellphone is charged).

If you connect a light load (Arduino) to a powerbank, it might turn on/off uncontrolled.
That could explain the noise you're hearing.
Leo..

On top of the switching…can also be interesting for some powerbanks when measuring the 5 volt output with an oscilloscope. Some are shockingly noisy… poor filtering.

@Wawa It's only those cheap powerbanks that makes this noise. I've since tried Huawei and Xiaomi and they output fine without any noise on the Nano.

A Nano has minimal smoothing (caps) on it's 5volt rail (no room for big caps).
Try a 47uF electrolytic cap between the 5volt pin and the ground pin of the Nano.
Leo..