read characteristic value

[abhatikar]

Hello,

I am running this code on my peripheral that sends battery level periodically. But I am not able to get it. A simple read_val also does not work. Please help.

Ubuntu 18.04

import gatt
from argparse import ArgumentParser

class AnyDevice(gatt.Device):
    def services_resolved(self):
        super().services_resolved()

        battery_information_service = next(
            s for s in self.services
            if s.uuid == '00001801-0000-1000-8000-00805f9b34fb')

        for c in battery_information_service.characteristics:
            c.enable_notifications(True)

        print("Reading Battery")

    def characteristic_value_updated(self, characteristic, value):
        print("Battery level:", value.decode("utf-8"))

arg_parser = ArgumentParser(description="GATT Read Firmware Version Demo")
arg_parser.add_argument('mac_address', help="MAC address of device to connect")
args = arg_parser.parse_args()

manager = gatt.DeviceManager(adapter_name='hci0')

device = AnyDevice(manager=manager, mac_address=args.mac_address)
device.connect()

manager.run()

[abhatikar]

Please let me know if I am missing something

[abhatikar]

gatttool utility seems to work. Please help how to use this library. Thanks in advance,

gatttool -b "aa:4f:9f:55:30:00" -I
[aa:4f:9f:55:30:00][LE]> connect
Attempting to connect to aa:4f:9f:55:30:00
Connection successful
[aa:4f:9f:55:30:00][LE]> char-desc
handle: 0x0001, uuid: 00002800-0000-1000-8000-00805f9b34fb
handle: 0x0002, uuid: 00002803-0000-1000-8000-00805f9b34fb
handle: 0x0003, uuid: 00002a00-0000-1000-8000-00805f9b34fb
handle: 0x0004, uuid: 00002803-0000-1000-8000-00805f9b34fb
handle: 0x0005, uuid: 00002a01-0000-1000-8000-00805f9b34fb
handle: 0x0006, uuid: 00002800-0000-1000-8000-00805f9b34fb
handle: 0x0007, uuid: 00002803-0000-1000-8000-00805f9b34fb
handle: 0x0008, uuid: 00002a05-0000-1000-8000-00805f9b34fb
handle: 0x0009, uuid: 00002902-0000-1000-8000-00805f9b34fb
handle: 0x000a, uuid: 00002800-0000-1000-8000-00805f9b34fb
handle: 0x000b, uuid: 00002803-0000-1000-8000-00805f9b34fb
handle: 0x000c, uuid: 00002a19-0000-1000-8000-00805f9b34fb
handle: 0x000d, uuid: 00002902-0000-1000-8000-00805f9b34fb
[aa:4f:9f:55:30:00][LE]> char-write-req 0x000d 0100
Characteristic value was written successfully
Notification handle = 0x000c value: 05
Notification handle = 0x000c value: 04
Notification handle = 0x000c value: 05
Notification handle = 0x000c value: 06
Notification handle = 0x000c value: 05
Notification handle = 0x000c value: 04
Notification handle = 0x000c value: 05
Notification handle = 0x000c value: 06
Notification handle = 0x000c value: 05
Notification handle = 0x000c value: 06
Notification handle = 0x000c value: 05
Notification handle = 0x000c value: 04
Notification handle = 0x000c value: 05
Notification handle = 0x000c value: 04
Notification handle = 0x000c value: 05
[aa:4f:9f:55:30:00][LE]> disconnect

[retorik]

Hi, same issue for me ! Have you found a solution ? Thx Jeremy

[abhatikar]

I didn't use the gatt-python. I wrote a C application to interact with BLE device.