lora_receiver.py

from machine import Pin, SoftSPI
from sx127x import SX127x #https://github.com/abuvanth/micropython-sx127x/blob/master/sx127x.py
import neopixel
from time import sleep

# Define the pins (adjust based on your ESP32 board and wiring)
MOSI_PIN = 4
MISO_PIN = 0
SCK_PIN = 1
NSS_PIN = 5
DIO0_PIN = 10
pin = Pin(7, Pin.OUT)   # Example pin number
np = neopixel.NeoPixel(pin, 1)
# Configure the SPI interface
spi = SoftSPI(baudrate=10000000, polarity=0, phase=0, bits=8, firstbit=SoftSPI.MSB, sck=Pin(SCK_PIN), mosi=Pin(MOSI_PIN), miso=Pin(MISO_PIN))

# Configure NSS and DIO0
nss = Pin(NSS_PIN, mode=Pin.OUT, value=1)
dio0 = Pin(DIO0_PIN, mode=Pin.IN)

# LoRa configuration - should match the sender's configuration
lora_config = {
    'frequency': 433E6,        
    'tx_power_level': 20,       
    'signal_bandwidth': 125E3,  
    'spreading_factor': 12,     
    'coding_rate': 5,           
    'preamble_length': 12,     
    'implicit_header': False,   
    'sync_word': 0x12,         
    'enable_crc': True,         
    'invert_iq': False,         
}

# Initialize LoRa
lora = SX127x(spi, pins={'miso': MISO_PIN, 'mosi': MOSI_PIN, 'ss': NSS_PIN, 'sck': SCK_PIN, 'dio_0': DIO0_PIN}, parameters=lora_config)

# Function to receive a message
def on_receive(lora, payload):
    try:
        msg = payload.decode()
        rssi_value = lora.packetRssi()  # Get the RSSI value
        if rssi_value >= -50:
            np[0] = (0, 255, 0)  # Green for very strong signal
        elif -70 <= rssi_value < -50:
            np[0] = (0, 0, 255)  # blue for strong signal
        elif -90 <= rssi_value < -70:
            np[0] = (0, 255, 255)  # purple for moderate signal
        elif -110 <= rssi_value < -90:
            np[0] = (255, 0, 0)  # Red for weak signal
        else:
            np[0] = (128, 128, 128)  # Grey for very weak or no signal
        np.write()
        print("Received message:", msg)
    except Exception as e:
           print(e)
    np[0] = (0, 0, 0)  # off
    np.write()
            
lora.onReceive(on_receive)

# Set the LoRa module to listen mode
lora.receive()

while True:
    # Your main loop where other tasks can be performed
    pass