powering Arduino nano from USB and NRF24L01+ from AA batteries. Not working

[garubi]

Hi all,
first post here, even if I'm lurking from several months ago.
My name is Stefano, I have some experience with Arduinos, Teensy, ESPs. I'm running an Home Assistant controller, and I'm already using some basic MySensors nodes.

I'm experimenting with a test node where the Arduino Nano is powered via USB and the NRF24L01+ radio is powered from 2 AA batteries in series.
The node is booting up (I get MySensors banner and data in serial console) but the radio does not initialize.
I understood that the NRF24 can be powered directly from 3V batteries, isn't it?

If I connect the radio to the 3.3V and GND pin of Arduino it runs ok. It's just when powered from batteries that it doesn't initialize...

Any clue?

p.s.
Some context information:

• all the others radio's pin are connected to the Arduino in the same way both when powered with batteries taht when powered from Arduino
• I checked the batteries with multimeter and they, in series, provides around 3.1Volts. I think it's enough, isn't it?
• Why am I doing this? well I'm trying to test if I can get better radio performances by powering it from a "cleaner" current (batterties) instead of the 3.3V from Arduino.

Thanks for your help

[mfalkvidd]

@garubi is gnd on the nrf24 connected to gnd on the Arduino?

[garubi]

@mfalkvidd no, at the moment it's connected to the negative pole of the battery.
So the V+ of the radio to to the positive of the battery and the GND to the negativa

[mfalkvidd]

@garubi they’ll need common ground to be able to communicate.

Connect gnd on the Arduino to gnd on the nrf24 (in addition to the existing connections).

[garubi]

:man-facepalming: I'm really a nooob! :laughing:
Thank you, I'll try as soon as possible...
So to recap:
Arduino GND -> Radio GND
Arduino 3V3 -> unconnected
Battery GND -> Radio GND
Battery + -> Radio VCC

Is it corrrect?

Thank you again
Stefano

[mfalkvidd]

@garubi yes, you got it right

We were all noobs at some point :)

[garubi]

Just for others coming here in the future: I changed the connections as suggested by @mfalkvidd , restarted the node and now the radio runs from batteries and the Arduino is powered from USB (phone charger).

Unfortunately this doesn't seem to have improved the radio communication, but this is another story...
Stefano