Infinity

A hacker's Thinking

Convert iBeacon to Eddystone

| Comments

Beacons are new way for contextual suggestions to the users. Beacons uses BLE to transmit the information. This post is to explain how can you use Google Eddystone protocol without actually converting them into the Eddystone.

To get started with this article, you must know little knowledge of the Beacons and iBeacon & Eddystone Protocol.

Here is my logic to convert iBeacon to Eddystone Advertised id in Python:

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48

def advertised_id(self):
    """
    Convert uuid, major, minor into advertised id
    """
    namespace = '0x' + self.uuid[:8] + self.uuid[-12:]
    major, minor = map(int, (self.major, self.minor))
    temp_instance = self._append_hex(major, minor)
    instance = self._add_padding(temp_instance)
    beacon_id = self._append_hex(int(namespace, 16), instance)
    return base64.b64encode(self.long_to_bytes(beacon_id))

def _add_padding(self, instance):
    """
    Append padding of desired size
    """
    bit_length = (len(hex(instance)) - 2) * 4
    desired_padding_size = self.desired_instance_bits - bit_length
    padding = (2 ** desired_padding_size) - 1
    return self._append_hex(padding, instance)

def _append_hex(self, a, b):
    """
    Append hex number a in front of b
    """
    sizeof_b = 0

    # Count the number of bits in b
    while((b >> sizeof_b) > 0):
        sizeof_b += 1

    # make number of bits perfectly divisible by 4
    sizeof_b += 4 - ((sizeof_b % 4) or 4)

    return (a << sizeof_b) | b

def long_to_bytes(self, value, endianness='big'):
    """
    Convert hexadecimal into byte array
    """
    width = value.bit_length()
    width += 8 - ((width % 8) or 8)
    fmt = '%%0%dx' % (width // 4)
    s = unhexlify(fmt % value)

    if endianness == 'little':
        s = s[::-1]

    return s

For any doubt please write in comments.

Comments