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• Combine ABP and OTAA mode in one class

  Dominik Kuhn • 09/30/2024 at 13:41 • 0 comments

  By simplifying and extending our LoRaWAN class, we can develop applications with very little effort. Below is a small example in both modes to send a simple string message to The Things Network (TTN): 

  from machine import Pin, SPI
  import machine
  import time
  from random import randrange
  
  from PyLoRaWAN import PyLoRaWAN, ActivationType
  
  
  # The Things Network (TTN) device details (available in TTN console)
  # TTN device address, 4 Bytes, MSB (REPLACE WITH YOUR OWN!!!)
  devaddr = [0x26, 0x00, 0x00, 0x00]
  # TTN network session key, 16 Bytes, MSB (REPLACE WITH YOUR OWN!!!)
  nwskey = [0xE0, 0x92, 0xEA, 0x35, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00]
  # TTN application session key, 16 Bytes, MSB (REPLACE WITH YOUR OWN!!!)
  appskey = [0xB2, 0xB5, 0xC8, 0xDF, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00]
  
  
  deveui = [0x70, 0xB3, 0xD5, 0x00, 0x00, 0x00, 0x00, 0x00]
  appeui = [0x45, 0x23, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00]
  appkey = [0x44, 0x99, 0xB4, 0xD3, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00]
  devnonce = [randrange(256), randrange(256)]
  
  
  spi = machine.SPI(0,
      baudrate=100000,
      polarity=1,
      phase=1,
      bits=8,
      firstbit=machine.SPI.MSB,
      sck=machine.Pin('GP2'),
      mosi=machine.Pin('GP3'),
      miso=machine.Pin('GP4')) 
  
  cs = machine.Pin( 'GP5' ) # , Pin.OUT, value=1)
  
  time.sleep(10)
  
  lorawan = PyLoRaWAN(spi, cs)
  lorawan.modem.set_output_power(16)
  lorawan.modem.set_spreading_factor(12)
  
  lorawan.join( ActivationType.ABP, auth={'devaddr':devaddr, 'nwskey':nwskey, 'appskey':appskey} )
  
  for i in range(5):
      lorawan.send_test_msg()
      time.sleep(60)
  
  time.sleep(5)
  
  lorawan.join( ActivationType.OTAA, auth={'deveui':deveui, 'appeui':appeui, 'appkey':appkey, 'devnonce':devnonce} )
  
  for i in range(5):
      lorawan.send_test_msg()
      time.sleep(60)

  We are still developing and present more details later. Then we will also publish the link to our GitHub repo with the hardware and software for our board. 

• First tests with Micropyton

  Dominik Kuhn • 09/12/2024 at 18:05 • 0 comments

  We added a port to Micropython for this board, so to be able to make the first tests. We wrote several Python modules to send and receive all 4 data message types of the LoRaWAN 1.0.x and 1.1 standards. These message types are used to transport MAC commands and application data. So we were now able to communicate with TTN successfully in ABP and OTAA modes. In addition, we have written an overriding class for low level hardware control of the SX1276 module. 

  More details later.

• Rev 1.1 - 2024.09

  Dominik Kuhn • 09/12/2024 at 17:41 • 0 comments

  • Optimazations:
    • Trace width adjusted for a 50 Ohm antenna based on the JLCPCB impedance calculator.
    • SMA connection mirrored, to remove a via to the upper side, which possibly made trouble.
    • Ground area around the antenna trace in the clearance set to 10 mil as in the JLCPCB impedance calculator.
    • Adding a 100nF ceramic capacitor (MLCC) close to the LoRa module.

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