LoPy ABP Example

End Devices (Nodes) Pycom
21

But if I convert the DevAddr assigned by TTN to INT it results in 2590387051 and this also gives an error:

>>> # create an ABP authentication tuple (NwkSKey, AppSKey, DevAddr)
>>> auth = (bytes([0x58, 0xB9, 0x47, 0x74, 0xAF, 0x6F, 0x97, 0x43, 0xEA, 0x0C, 0x58, 0xC5, 0x12, 0xA1, 0xDE, 0x68]), bytes([0x32, 0x83, 0xB1, 0xD7, 0x99, 0x05, 0x83, 0x29, 0x8F, 0xE5, 0xE4, 0xE8, 0x1A, 0xE7, 0x0E, 0xD6]), 2590387051)
>>>
>>> # join a network using ABP (Activation By Personalization)
>>> lora.join(activation=LoRa.ABP, auth=auth, timeout=0)
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
OverflowError: overflow converting long int to machine word
22

Just experimented a little: Values up to 0x7FFFFFFF are OK but 0x80000000 and higher raise an overflow
My guess is that a signed type was used instead of an unsigned type to represent the dev-addr
You can work around this by choosing a dev-addr that is below 0x80000000

But As @kruisdraad mentions ABP isnā€™t working yet, only the first package arrivĆ©s, but if that feels like an achievement, just go ahead :slight_smile:

A few things seem to be missing from the code?
import pycom
setting of GREEN to 0x00FF00

23

Thanks for your tipsā€¦
Indeed the code was missing some lines :grinning:

But one more question: in ABP I cannot choose my own dev-addr as far a I know? So how should I choose one below 0x7FFFFFFF ?

24

Use the ttnctl command like mentioned here by @arjanvanb
And please change your keys because now they are known to the world :blush:

25

Thank you so muchā€¦finally I got my first message through!!!

Now time for my sodaq :wink:

(and yes, I will change those keys :wink:

26

perhaps @danicampora can that that value type / signed / unsigned in account with the next release

29

Yes I hope so, I reported the problem on the Pycom forum. But at least there is a workaround by choosing your device address when using the ttnctl command as mentioned above. So itā€™s not as blocking as the 1 packet issue.

30

I probably donā€™t need it if I donā€™t know what it isā€“but Iā€™m curious and canā€™t help asking. Whatā€™s ABP?

31

This topic is probably a good starter for your question.

For more information please refer to this nice starting point:

1 Like
32

Hi all, Daniel Campora is working on a guide for using TTN with LoPy. You can find the current draft at:

https://www.thethingsnetwork.org/docs/draft/lopy/

If you have corrections or suggestions, just use the edit button to do a quick PR!

33

as long as stuff aint working, i am not spending another minute on the LoPy

That includes building docs

2 Likes
34

think there has been an update !

35

think its still not working, not even the new examples

36

Cant get the wifi working wither to be able to upload files to the LoPy with the new firmware. When I setup wifi to be a station it crashes

37

posted a working example using a Lopy with the latest firmware using OTAA and a Pi3 gateway in this topic:

PyCom announcing a new module: FiPy

38

The LoPy Works. Upgrade to latest PyMakr and firmware from the website and you can use the following example:

from network import LoRa
from time import sleep

import socket
import binascii
import struct

# Initialize LoRa in LORAWAN mode.
lora = LoRa(mode=LoRa.LORAWAN, sf=7, tx_power=14)

lora.BW_125KHZ
lora.CODING_4_5

# create an ABP authentication params
dev_addr = struct.unpack(">l", binascii.unhexlify('XX XX XX XX'.replace(' ','')))[0]
nwk_swkey = binascii.unhexlify('XX XX XX XX XX XX XX XX XX XX XX XX XX XX XX XX'.replace(' ',''))
app_swkey = binascii.unhexlify('XX XX XX XX XX XX XX XX XX XX XX XX XX XX XX XX'.replace(' ',''))

# join a network using ABP (Activation By Personalization)
lora.join(activation=LoRa.ABP, auth=(dev_addr, nwk_swkey, app_swkey))

# create a LoRa socket
s = socket.socket(socket.AF_LORA, socket.SOCK_RAW)

# set the LoRaWAN data rate
s.setsockopt(socket.SOL_LORA, socket.SO_DR, 5)

# make the socket blocking.
s.setblocking(True)

while True:
    #Do you stuff make data and then send in a loop
    print("sending")
    s.send('hello')
    print("done")
    sleep(5)
2 Likes
39

Hi, I see a couple of likes but can anyone confirm they have this code working?

40

try it, it works fine ā€¦ as long as you donā€™t want to change the DR/SF

41

When Iā€™m using the ABP method it always returns true on lora.has_joined(),
Iā€™ve tried to send a few messages with this method but only one actually came through to TTN.

I did also try the OTAA message, in this case the has_joined function does seem to work and messages get through to TTN more often (But after one message I need to reset the board).

42

are you running the latest firmware?