The library for Lora: go to this website to download zip

https://github.com/PaulStoffregen/RadioHead

The code for the Arduino Nano on the transmitter side

Configuring the Raspberry Pi for LoRa module

The python code for the raspberry pi on the receiver side

from time import sleep

from SX127x.LoRa import *

from SX127x.board_config import BOARD

BOARD.setup()

class LoRaRcvCont(LoRa):

def __init__(self, verbose=False):

super(LoRaRcvCont, self).__init__(verbose)
   
        #self.set_bw(9)
        #self.set_freq(434)
       
        self.set_mode(MODE.SLEEP)
        self.set_dio_mapping([0, 0, 0, 0, 0, 0])

def start(self):

self.reset_ptr_rx()

self.set_mode(MODE.RXCONT)

while True:

sleep(.5)

rssi_value = self.get_rssi_value()
            #print(rssi_value)
           
            status = self.get_modem_status()
            #print(self.get_modem_status())
            sys.stdout.flush()

def on_rx_done(self):

self.clear_irq_flags(RxDone=1)
        self.set_modem_config_1()
        payload = self.read_payload(nocheck=True)
    
        data=(bytearray(payload).decode('utf-8','ignore'))
        
        signal=str(self.get_pkt_rssi_value())
        
        print("temp:"+data[2:7]+","+"signalstrength:"+signal)
               
        self.set_mode(MODE.SLEEP)

self.reset_ptr_rx()

self.set_mode(MODE.RXCONT)

lora = LoRaRcvCont(verbose=False)

lora.set_mode(MODE.STDBY)

#  Medium Range  Defaults after init are 434.0MHz, Bw = 125 kHz, Cr = 4/5, Sf = 128chips/symbol, CRC on 13 dBm

lora.set_pa_config(pa_select=1)
#print(lora)

try:

lora.start()

except KeyboardInterrupt:

sys.stdout.flush()

print("")

sys.stderr.write("KeyboardInterrupt\n")

finally:

sys.stdout.flush()

print("")

lora.set_mode(MODE.SLEEP)

BOARD.teardown()

Node-RED flows on the receiver side

[
    {
        "id": "6bf2dddaef6f6567",
        "type": "tab",
        "label": "Flow 2",
        "disabled": false,
        "info": "",
        "env": []
    },
    {
        "id": "6b76e1b1d649a93b",
        "type": "inject",
        "z": "6bf2dddaef6f6567",
        "name": "",
        "props": [
            {
                "p": "payload"
            },
            {
                "p": "topic",
                "vt": "str"
            }
        ],
        "repeat": "",
        "crontab": "",
        "once": true,
        "onceDelay": 0.1,
        "topic": "",
        "payload": "",
        "payloadType": "date",
        "x": 110,
        "y": 100,
        "wires": [
            [
                "563791fdd31ec8d3"
            ]
        ]
    },
    {
        "id": "c7dd2e4c0ce9a1cf",
        "type": "debug",
        "z": "6bf2dddaef6f6567",
        "name": "debug 9",
        "active": true,
        "tosidebar": true,
        "console": false,
        "tostatus": false,
        "complete": "false",
        "statusVal": "",
        "statusType": "auto",
        "x": 360,
        "y": 80,
        "wires": []
    },
    {
        "id": "563791fdd31ec8d3",
        "type": "exec",
        "z": "6bf2dddaef6f6567",
        "command": "python3 /home/myson/Adrunio_Rasp_Sx1278.py",
        "addpay": "",
        "append": "",
        "useSpawn": "true",
        "timer": "",
        "winHide": false,
        "oldrc": false,
        "name": "",
        "x": 350,
        "y": 180,
        "wires": [
            [
                "c7dd2e4c0ce9a1cf"
            ],
            [],
            []
        ]
    }
]