BLE notifications with FIPY as client

[Fredrik Andersson]

Hi, can't get callback(trigger=Bluetooth.CHAR_NOTIFY_EVENT, handler=char_notify_callback,arg=None) to work. Read some threads and some say it is not possible to use notification (due to missing descriptor functions..) other report that it does work.

Can anyone clarify this?

[Meriç SARIIŞIK]

Hi Fredrik,

First of all, CHAR_NOTIFY_EVENT works well on FiPy.
Could you tell me which version you are using? I tried my example on different versions and I haven't seen a missing descriptor error.
You can try the examples below. Please let me know about your experiment.

BR,
Meric

Subscribe_Event

def chr1_handler(chr, data):
    global battery
    global update
    events = chr.events()
    print("events: ",events)
    if events & (Bluetooth.CHAR_READ_EVENT | Bluetooth.CHAR_SUBSCRIBE_EVENT):
        chr.value(battery)
        print("transmitted :", battery)
        if (events & Bluetooth.CHAR_SUBSCRIBE_EVENT):
            update = ~update

bluetooth = Bluetooth()
bluetooth.set_advertisement(name='FiPy 45', manufacturer_data="Pycom", service_uuid=0xec00)

bluetooth.callback(trigger=Bluetooth.CLIENT_CONNECTED | Bluetooth.CLIENT_DISCONNECTED, handler=conn_cb)
bluetooth.advertise(True)

srv1 = bluetooth.service(uuid=0xec00, isprimary=True,nbr_chars=1)

chr1 = srv1.characteristic(uuid=0xec0e, value='read_from_here') #client reads from here

chr1.callback(trigger=(Bluetooth.CHAR_READ_EVENT | Bluetooth.CHAR_SUBSCRIBE_EVENT), handler=chr1_handler)

def update_handler(update_alarm):
    global battery
    global update
    battery-=1
    if battery == 1:
        battery = 100
    if update:
        chr1.value(battery)

update_alarm = Timer.Alarm(update_handler, 1, periodic=True)

Notify_Event

def char_notify_callback(char, arg):
    char_value = (char.value())
    print("New value: {}".format(char_value))

bt = Bluetooth()
bt.start_scan(-1)
adv = None
while(True):
    adv = bt.get_adv()
    if adv:
        try:
            if bt.resolve_adv_data(adv.data, Bluetooth.ADV_NAME_CMPL)=="FiPy 45":
                conn = bt.connect(adv.mac)
                try:
                    services = conn.services()
                    for service in services:
                        time.sleep(0.50)
                        chars = service.characteristics()
                        for char in chars:
                            c_uuid = char.uuid()
                            if c_uuid == 0xec0e:
                                if (char.properties() & Bluetooth.PROP_NOTIFY):
                                    char.callback(trigger=Bluetooth.CHAR_NOTIFY_EVENT, handler=char_notify_callback)
                                    print(c_uuid)
                                    break
                except:
                    continue
        except:
            continue

bt.stop_scan()
bt.disconnect_client()