FSK dog collar packet dissection

fsk_dog_collar.py

#!/usr/bin/env python

from bitarray import bitarray


start = "101001110001000100010010"
ends = ["1000000000100100",
        "0100000011100100",
        "1100000001100100",
        "0010000010000100",
        "1010000000000100"]

for block in [bitarray(start + e, endian='little') for e in ends]:
    xor = reduce(lambda x, y: x ^ y,
                 [ord(c) for c in block.tobytes()[:-1]])
    print xor, ord(block[-8:].tobytes())

output.txt

36 36
39 39
38 38
33 33
32 32