Arduino Micro DC noise

Hi, I'm finishing a project on a Midi control pedalboard. Feed the pedalboard with a 1700mAh transformer and in turn this transformer feeds some of the effects it controls. The sum of the consumption of everything does not reach even 1400mAh.

It turns out that when I connect the Arduino the effects connected to the same transformer make noise.

I changed the transformer, reduced the load and continue to produce alike, so I think it is the Arduino and connected components.

Anyone know if there is a filter that eliminates these noises?

Thanks and regards.

You mean mA, not mAh.

The Arduino is digital electronics, which always inject lots of noise onto its power supply, and this typically overlaps the audio spectrum.

What voltage is the supply? Are you connecting it to Vin or is it 5V?

Good filtering of the power supply should help, which can mean another linear regulator and big bypass capacitors, or an LC pi filter.

In general its best not to power digital and senstive analog from the same power rail, separate voltage regulators for each is a common approach.

The quickest short-term approach is to try lots of electrolytic decoupling on the Arduino, 1000uF or so on the 5V rail, coupled with 10 ohms series resistor between your supply and the Arduino's supply pin - basically a big RC filter. Note that this means the Arduino voltage may drop below 5V a bit.

Sorry, mean mA. The power supply is connected to Vin and is in 9v.

I've found this post: and I'll be try it.

Use the last schematic on this page:-