Wireless Lab 2

tags: `Wireless`

實驗結果

跑完OTAA傳輸模式的流程，分別截圖join_ttn.py,send_ttn.py的結果
將send_ttn.py的message改成:Wireless Lab2
傳輸資料後用MQTT查看，並用base64解密截圖。
以組為單位(一個人上傳即可)，將這些截圖結果貼成一個word檔案，命名為wireless-lab2-groupxx.docx，並上傳到LMS作業區。

What is OTAA?

OTAA模式送出 (join_ttn.py)

這份程式主要修改來自 jeroennijhof 的程式碼

$ git clone https://github.com/Ox7FFFFFFF/Wireless-Lab2

程式資料夾
LoRaWAN - 與LoRaWAN相關的程式
SX127x - 控制晶片的SPI程式
send_ttn.py - 資料送出
join_ttn.py - 送出Join封包
config.json - Activated [DevAddr, NwkSKey, AppSKey]配置

在join_ttn.py填入deveui,appeui,appkey

DEV_EUI : 000000000000001x (x=組別)





# Init
deveui = list(bytearray.fromhex('DEV_EUI')) #輸入你組別裝置EUI
appeui = list(bytearray.fromhex('1234efc7104f1230')) #勿動
appkey = list(bytearray.fromhex('a346b6faef2bd33c16fe9b1d8d47a11d')) #勿動
devnonce = [randrange(256), randrange(256)]

發送Join Request，裡面會帶入deveui,appeui,devnonce






    def join(self):
        lorawan = LoRaWAN.new(appkey)
        lorawan.create(MHDR.JOIN_REQUEST, {'deveui': deveui, 
        'appeui': appeui, 'devnonce': devnonce})
        self.write_payload(lorawan.to_raw())
        self.set_mode(MODE.TX)

送出uplink後，會跳到on_tx_done










    def on_tx_done(self):
        self.clear_irq_flags(TxDone=1)
        print("TxDone")
        # 切換到rx
        self.set_mode(MODE.STDBY)
        self.set_dio_mapping([0,0,0,0,0,0])
        self.set_invert_iq(1)
        self.reset_ptr_rx()
        sleep(4)
        self.set_mode(MODE.RXCONT)

當收到downlink時，會跳到on_rx_done




































    def on_rx_done(self):
        print("RxDone")

        self.clear_irq_flags(RxDone=1)
        payload = self.read_payload(nocheck=True)

        lorawan = LoRaWAN.new([], appkey)
        lorawan.read(payload)
        lorawan.get_payload()
        # 判斷格式是否為JOIN_ACCEPT
        if lorawan.get_mhdr().get_mtype() == MHDR.JOIN_ACCEPT:
            print("get mic: ",lorawan.get_mic())
            print("compute mic: ",lorawan.compute_mic())
            print("valid mic: ",lorawan.valid_mic())

            # 判斷downlink是不是自己的
            if lorawan.valid_mic():
                devaddr = binary_array_to_hex(lorawan.get_devaddr())
                nwskey = binary_array_to_hex(lorawan.derive_nwskey(devnonce))
                appskey = binary_array_to_hex(lorawan.derive_appskey(devnonce))
                print("devaddr:",devaddr)
                print("nwskey :",nwskey)
                print("appskey:",appskey)

                # 將收到的devaddr,nwskey,appskey寫到檔案中
                config = {'devaddr':devaddr,'nwskey':nwskey,'appskey':appskey,'fCnt':0}
                data = json.dumps(config, sort_keys = True, indent = 4, separators=(',', ': '))
                fp = open("config.json","w")
                fp.write(data)
                fp.close()
                print("Join Accept")
                sys.exit(0)

            else:
                print("Fail to join!")
                sys.exit(0)