Breaduino (Atmega328p) as Mysensors Node (NRF24L01+) - will it work?

[Petr Nosek]

Hi everyone,
nearly two years I build small nodes for my Domoticz system with my sensors. It is AWESOME!
I need to build few nodes, which will be really very little power hungry running on 3 AA batteries. I first tried to use the Pro MINI Arduino, but whenever I cut the LEDs on th board, the Arduino died.

So I decided to build a really minimalistic Arduino only using the Atmega328P chip, 16hz crystal, capacitors and restores as described here: https://www.arduino.cc/en/Main/Standalone (just removed the pin 13 led as I need pin 13 for radio). I power it with 3.3V now on the breadboard.

I was able to run such "breaduino" with all basic scripts like blink etc., but as soon as I load any MySensors sketch, it basically does nothing.
I do not doubt it is my mistake, but I can not figure out, what is wrong.

Does anyone has such minimalistic device running? Is there any specific code which needs to be changed? I am on 2.2.0 version of the library.

I will appreciate any experience or hint.
Thanks for your answers.

[kimot]

@petr-nosek said in Breaduino (Atmega328p) as Mysensors Node (NRF24L01+) - will it work?:

Atmega328P
It must work on breadboard.
And you cannot damage Arduino Pro Mini by removing LED only.

16MHz and 3.3 V is out of specification.
Therefore Arduino for 3.3v uses 8MHz.

https://www.ebay.com/itm/NEW-Pro-Mini-ATMEGA328P-5V-16M-3-3V-8M-Optional-Arduino-PRO-mini-Compatible/322733156356?hash=item4b24652804:m:mu7vfkUp6EGgxFbtG1p2IDQ

[Petr Nosek]

Thanks Kimot. I did use 3,3V voltage as the radio NRF24L01+ is supposed to run on 3,3V only. I did not realise that it affect the crystal frequency. When I now tested with 5V it works perfectly! I will purchase an 8Mhz crystal instead and try it all on 3,3V with a step up booster 1,5 -3,3 to 3,3 V with AA batteries.

Regarding the "broken" pro mini - I must have broken something else too, as after removing the connection in front of the sms led it unfortunately stopped responding to communicate. So I must have destroyed more than just the LED.

Anyway, I am happy I was able to built my own "arduino node" with only the chip, crystal and few capacitors and resistors. It is great to see it working!

Thanks for your help.