Node with RFM95 and Arduino Pro Mini (Atmega168)

(Algram) #1

Hi there,
has anyone ever used a Pro Mini with the Atmega168 chip as a LoRa node? If yes, could you please point me to some code?

I have searched countless hours now, but the only thing that ever pops up is for the Atmega328.



Wel the reason that you don’t find code for the ATmega168 is because of the footprint of the RFM95 library. It just won’t fit in a 16K microcontroller. You will need at least a Atmega328 microcontroler when you want to use the RFM95 with TTN.

(Algram) #3

Okay so is there any kind of wiring diagram for an Arduino Nano and the RFM95?

Also, if it does not work with 16K microcontrollers, how are people managing to create ATtiny nodes? Isn’t that the same thing?

Thanks for your help!


For that there are variouse options, but most use a special library like in this project : . That project also includes the wirering for the TINY85.

But remember these implementations don’t use a port of the LMIC library.

(Algram) #5

Okay thanks.
So a save bet would be to get an Arduino Pro Mini with the Atmega328 and the RFM95, correct?


And take the 3.3V version, not the 5V version of the Arduino Pro Mini 328p.

(Algram) #7

Alright. I have searched for some examples, but most of them have different wiring. Is there a good “go-to” example with a wiring scheme and some example code (just something sending a lora messag every 5 seconds or so)?

This would really help me since I need something I KNOW works, to test if my LoRa setup as a whole works. Right now it is more a guessing game of “Did I do something wrong hardware wise, or do I need to change the software”.

(Jens) #8


Not for Atmega168 but for Atmega 328p 3,3V

Have a look:



look at this
I‘m using it for several nodes

(Algram) #10

Hm seems a little expensive if I have all the Arduino stuff here already.

(Bjacobse) #11

As I have Arduino Pro Mini and purchased a few RFM95w modules, I’m creating a schematic and PCB based on this:

I’m not there yet. My intention is to create a PCB that you can etch at home, via the “toner transfer method” you print on a laserprinter, on a glossy printerpaper, and use an iron to transer to copper PCB, and then etch

I will keep you notified when I’m ready to share

(Leo Korbee) #12


I’ve made an ATtiny84 with RFM95w module and BME280 environment sensor. Total code size: 7212 bytes, data: 139 bytes.
Maybe you can use this as starting point for your ATmega168.