main_BLE-battery.py

import ubluetooth as bluetooth
import struct
import time
from ble_advertising import advertising_payload

from micropython import const
_IRQ_CENTRAL_CONNECT                 = const(1 << 0)
_IRQ_CENTRAL_DISCONNECT              = const(1 << 1)

_BATTERY_UUID = bluetooth.UUID(0x180F)
_BATTERY_LEVEL_CHAR = (bluetooth.UUID(0x2A19), bluetooth.FLAG_READ|bluetooth.FLAG_NOTIFY,)
_BATTERY_SERVICE = (_BATTERY_UUID, (_BATTERY_LEVEL_CHAR,),)

class BLEBattery:
    def __init__(self, ble, name='mpy-bat-b'):
        self._ble = ble
        self._ble.active(True)
        self._ble.irq(handler=self._irq)
        ((self._handle,),) = self._ble.gatts_register_services((_BATTERY_SERVICE,))
        self._connections = set()
        self._payload = advertising_payload(name=name, services=[_BATTERY_UUID])
        self._advertise()

    def _irq(self, event, data):
        # Track connections so we can send notifications.
        if event == _IRQ_CENTRAL_CONNECT:
            conn_handle, _, _, = data
            self._connections.add(conn_handle)
        elif event == _IRQ_CENTRAL_DISCONNECT:
            conn_handle, _, _, = data
            self._connections.remove(conn_handle)
            # Start advertising again to allow a new connection.
            self._advertise()

    def set_level(self, level_percentage, notify=False):
        # Write the local value, ready for a central to read.
        self._ble.gatts_write(self._handle, struct.pack('<B', int(level_percentage)))
        if notify:
            for conn_handle in self._connections:
                # Notify connected centrals to issue a read.
                self._ble.gatts_notify(conn_handle, self._handle)

    def _advertise(self, interval_us=500000):
        self._ble.gap_advertise(interval_us, adv_data=self._payload)


def demo():
    ble = bluetooth.BLE()
    batt = BLEBattery(ble)
    i = 25
    while True:
        # Write every second, notify every 10 seconds.
        i = (i + 1) % 101
        print(i+" Battery")
        batt.set_level(i, notify=(i % 10 == 0))
        time.sleep_ms(1000)


if __name__ == '__main__':
    demo()