micropython iBeacon example

beacon.py

import struct
import ubluetooth as bt
from micropython import const

MANUFACTURER_ID         = const(0x004C)
DEVICE_TYPE             = const(0x02)
DATA_LENGTH             = const(0x15)
BR_EDR_NOT_SUPPORTED    = const(0x04)
FLAG_BROADCAST          = const(0x01)
MANUFACTURER_DATA       = const(0xFF)

def convert_tx_power(dbm):
    return dbm + 0xFF + 1

class iBeacon():
    def __init__(self, ble, uuid, major, minor, tx_power):
        # Setup BLE
        self.ble = ble
        self.ble.active(False)
        self.ble.active(True)
        print("BLE Activated")

        self.uuid = uuid
        self.major = major
        self.minor = minor
        self.tx_power = convert_tx_power(tx_power)
        self.adv_payload = self.create_payload()


    def create_payload(self):
        payload = bytearray()
            
        #Set advertising flag
        value    = struct.pack('B', BR_EDR_NOT_SUPPORTED)
        payload += struct.pack('BB', len(value) + 1, FLAG_BROADCAST) + value

        # Set advertising data
        value    = struct.pack('<H2B', MANUFACTURER_ID, DEVICE_TYPE, DATA_LENGTH) 
        value   += self.uuid
        value   += struct.pack(">2HB", self.major, self.minor, self.tx_power)
        payload += struct.pack('BB', len(value) + 1, MANUFACTURER_DATA) + value

        return payload


    def advertise(self, interval_us=100000):
        print("Advertising: " + str(self.adv_payload))
        self.ble.gap_advertise(None)
        self.ble.gap_advertise(interval_us, adv_data=self.adv_payload, connectable=False)


    def update(self, major, minor, advertise_interval):
        self.ble.active(False)

        self.major = major
        self.minor = minor
        self.adv_payload = self.create_payload()

        self.ble.active(True)
        self.advertise(advertise_interval)


def demo():
    beacon = iBeacon(
        ble         = bt.BLE(), 
        uuid        = bytearray((
                        0xa4, 0x95, 0xbb, 0x10, 0xc5, 0xb1, 0x4b, 0x44, 
                        0xb5, 0x12, 0x13, 0x70, 0xf0, 0x2d, 0x74, 0xde
                    )),
        major       = 62,
        minor       = 1050,
        tx_power    = -50,
    )

    beacon.advertise()

if __name__ == "__main__":
    demo()
    while True:
        pass

The advertising data comes from the ble spec. I would suggest looking up "ibeacon packet structure" to understand what needs to be used to advertise.

Thanks for the contribution, N3MIS15.

It doesn't seem to have any relevance to controlling the advertisement tx power using the currently available micropython library. Am I missing something here/

I was hoping that someone might be able to point me towards full documentation.