This is a wireless ATmega328P node that leverages the Lora ra-01 wireless module. Range on LoRa modules is fantastic. This particular node is designed to be easy to both assemble and solder. It runs from the ATmega328P's internal 8Mhz clock and is easily programmable from within the Arduino IDE as an "8Mhz Pro Mini." The LED is on pin 9 rather than pin 13 so as not to interfere with SPI communications. Because of the 4-pin I2C header, a temperature-humidity sensor can be easily plugged-in to make a complete wireless temperature-humidity node.

I'm not sure whether Mysensors has yet adopted LoRa modules, but if not yet, you can use the RadioHead library. The radio chip is the SX1278, the same as used in HopeRF's RFM95 module. The price on the Ra-01 is considerably less, however.

As with nodes I've made for HopeRF RFM69 series modules, I've moved parts from this node that are only used when the FTDI is connected and put them on a separate board. The advantage to this is that you don't need to put those parts on every node but rather just on a single external board that's used in conjunction with a typical FTDI for uploading programs. If anyone has interest, I can post the schematic and Gerber files for such an external board.

https://www.aliexpress.com/item/LoRa-Series-Ra-01-Spread-Spectrum-Wireless-Module-Ultra-10KM-433M-RF-Chip-SX1278/32799821469.html?spm=2114.13010608.0.0.QHflzh