LoRa-Workshop/micropython/lora_transceiver.py

from uPyLora import config_lora
from uPyLora.sx127x import SX127x
from uPyLora.controller_esp32 import ESP32Controller

class LoRaTransceiver:
    def __init__(self, spreadingfactor=7, bandwidth=125E3, frequency=868E6, syncword=0x12, display=None):
        """ set up radio module
        """
        self.controller = ESP32Controller()
        self.lora = self.controller.add_transceiver(SX127x(name='LoRa'), pin_id_ss=ESP32Controller.PIN_ID_FOR_LORA_SS, pin_id_RxDone=ESP32Controller.PIN_ID_FOR_LORA_DIO0)

        self.setSpreadingFactor(spreadingfactor)
        self.setSignalBandwidth(bandwidth) 
        self.setFrequency(frequency)
        self.setSyncWord(syncword)

        self.display = display

    def setSpreadingFactor(self, spreadingfactor):
        """ set spreading factor 
            possible values are  7-12 
        """
        self.spreadingfactor = spreadingfactor
        self.lora.setSpreadingFactor(spreadingfactor)
    
    def setFrequency(self, frequency):
        """ set frequency (= channel used) 
            for now only 868 Mhz and 868.1 MHz are supported
        """
        self.frequency = frequency
        self.lora.setFrequency(frequency)

    def setSignalBandwidth(self, bandwidth):
        """ set the bandwidth 
            possible values should be 125 kHz or 250 kHz according to EU 868 frequency plan
        """
        self.bandwidth = bandwidth
        self.lora.setSignalBandwidth(bandwidth)

    def setSyncWord(self, syncword):
        """ set the sync word 
            should be 0x12 for plain LoRa and 0x34 for LoRaWAN
        """
        self.syncword = syncword
        self.lora.setSyncWord(syncword)

    def send(self, data):
        """ send raw data 
        """
        data_hex = " ".join(list(map(lambda x: "{0:02x}".format(x), data))).upper()
        print("Sending data {}".format(data_hex))
        if self.display is not None:
            self.display.show_text_wrap("Sending data {}".format(data_hex))
        self.lora.println_raw(data)

    
    def send_string(self, message):
        """ send a message 
            message should be a string
        """
        print("Sending string {}".format(message))
        if self.display is not None:
            self.display.show_text_wrap("Sending string {}".format(message))
        self.lora.println(message)


    def recv(self):
        """ start listening for messages and output them on the console """
        print("Receiving at frequency {} with spreading factor {} ...".format(self.frequency, self.spreadingfactor))
        if self.display is not None:
            self.display.show_text_wrap("Receiving at frequency {} with spreading factor {} ...".format(self.frequency, self.spreadingfactor))

        while True:
            # check for new message
            if self.lora.receivedPacket():
                self.lora.blink_led()

                print(" got packet: ")
                try:
                    payload_bytes = bytes(self.lora.read_payload_raw())
                    payload_hex = " ".join(list(map(lambda x: "{0:02x}".format(x), payload_bytes))).upper()
                    payload_string = self.lora.read_payload_raw()
                    print("  length : {0}".format(len(payload_bytes)))
                    print("     hex : {0}".format(payload_hex))
                    print("   bytes : {0}".format(payload_bytes))
                    print("    RSSI : {0}\n".format(self.lora.packetRssi()))
                    if self.display is not None: 
                        self.display.show_text_wrap("Received: {0} RSSI: {1}".format(payload_bytes, self.lora.packetRssi()))

                except Exception as e:
                    print(e)