Radiosensor not working on 2 AA batteries

[Tsjippy]

I have tried to make a batttery powered sensor by connecting 2 AA batteries to a step up convertor, which outputs 3.3V. I hooked that up to a arduino pro mini 3.3v and connected a radiomodule (MY_RADIO_RF24).

The sytems work just fine when connected to my a FTDI adapter which is connected to my laptop.
It does not work when powered from batteries. In fact it even works when I power the arduino from batteries and power the radio module from the FTDI.

When its not working, it does send messages, but never receives an answer back from the gateway.
Any clue how I can fix this?

[mfalkvidd]

Welcome to the forum @Tsjippy

The nrf24 is very sensitive to unstable power. Most step-ups deliver unstable power.

What capacitor(s) are you using, and where are they connected?

If you haven’t already, check out https://forum.mysensors.org/topic/666/debug-faq-and-how-ask-for-help - especially number 5

See also https://www.mysensors.org/build/battery

[Tsjippy]

Thanks, I missed that!
I did not have a capacitor connected. After connecting a 47 uF and a 22 uF cappacitor, it works.
Thanks

[mfalkvidd]

Nice work @Tsjippy, thanks for reporting back!

[Tsjippy]

@mfalkvidd
I was to quick, it was working so I used it to solder a PCB. That did not work, so tested again on a breadboard. Now it did not work. So I tried:
4.7
22
33k
47
47+22

Both on the breadboard and directly connected, not with power from the batteries and from the arduino, but it not work. He never gets a reply back.

So it has worked, but know it doesn’t, when I connect a stable powersupply it works.

What else should I try?