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adafruit_ble_ibbq.py
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adafruit_ble_ibbq.py
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# SPDX-FileCopyrightText: 2020 Dan Halbert for Adafruit Industries
#
# SPDX-License-Identifier: MIT
"""
`adafruit_ble_ibbq`
================================================================================
BLE iBBQ Multiple Probe Thermometers
* Author(s): Dan Halbert for Adafruit Industries
Implementation Notes
--------------------
iBBQ protocol information is from https://gist.github.com/uucidl/b9c60b6d36d8080d085a8e3310621d64.
**Hardware:**
InkBird and EasyBBQ (from PyleUSA) are brands that use the iBBQ protocol in their products.
"""
try:
from typing import Optional, Tuple
except ImportError:
pass
import struct
import _bleio
from adafruit_ble.attributes import Attribute
from adafruit_ble.services import Service
from adafruit_ble.uuid import StandardUUID
from adafruit_ble.characteristics import Characteristic, ComplexCharacteristic
__version__ = "0.0.0+auto.0"
__repo__ = "https://github.com/adafruit/Adafruit_CircuitPython_BLE_iBBQ.git"
class _SettingsResult(ComplexCharacteristic):
"""Notify-only characteristic of results from SettingsData messages"""
uuid = StandardUUID(0xFFF1)
def __init__(self) -> None:
super().__init__(properties=Characteristic.NOTIFY)
def bind(self, service: "IBBQService") -> _bleio.PacketBuffer:
"""Bind to an IBBQService."""
bound_characteristic = super().bind(service)
bound_characteristic.set_cccd(notify=True)
# Use a PacketBuffer that can store one packet to receive the data.
return _bleio.PacketBuffer(bound_characteristic, buffer_size=1)
class _RealtimeData(ComplexCharacteristic):
"""Notify-only characteristic of results from temperature probes"""
uuid = StandardUUID(0xFFF4)
def __init__(self) -> None:
super().__init__(properties=Characteristic.NOTIFY)
def bind(self, service: "IBBQService") -> _bleio.PacketBuffer:
"""Bind to an IBBQService."""
bound_characteristic = super().bind(service)
bound_characteristic.set_cccd(notify=True)
# Use a PacketBuffer that can store one packet to receive the data.
return _bleio.PacketBuffer(bound_characteristic, buffer_size=1)
class IBBQService(Service):
"""Service for reading from an iBBQ thermometer."""
_CREDENTIALS_MSG = b"\x21\x07\x06\x05\x04\x03\x02\x01\xb8\x22\x00\x00\x00\x00\x00"
_REALTIME_DATA_ENABLE_MSG = b"\x0B\x01\x00\x00\x00\x00"
_UNITS_FAHRENHEIT_MSG = b"\x02\x01\x00\x00\x00\x00"
_UNITS_CELSIUS_MSG = b"\x02\x00\x00\x00\x00\x00"
_REQUEST_BATTERY_LEVEL_MSG = b"\x08\x24\x00\x00\x00\x00"
def __init__(self, service: Optional["IBBQService"] = None) -> None:
super().__init__(service=service)
# Defer creating buffers until needed, since MTU is not known yet.
self._settings_result_buf = None
self._realtime_data_buf = None
uuid = StandardUUID(0xFFF0)
settings_result = _SettingsResult()
account_and_verify = Characteristic(
uuid=StandardUUID(0xFFF2),
properties=Characteristic.WRITE,
read_perm=Attribute.NO_ACCESS,
)
"""Send credentials to this characteristic."""
# Not yet understood, not clear if available.
# history_data = Characteristic(uuid=StandardUUID(0xFFF3),
# properties=Characteristic.NOTIFY,
# write_perm=Attribute.NO_ACCESS)
realtime_data = _RealtimeData()
"""Real-time temperature values."""
settings_data = Characteristic(
uuid=StandardUUID(0xFFF5),
properties=Characteristic.WRITE,
read_perm=Attribute.NO_ACCESS,
)
"""Send control messages here."""
def init(self) -> None:
"""Perform initial "pairing", which is not regular BLE pairing."""
self.account_and_verify = self._CREDENTIALS_MSG
self.settings_data = self._REALTIME_DATA_ENABLE_MSG
def display_fahrenheit(self) -> None:
"""Display temperatures on device in degrees Fahrenheit.
Note: This does not change the units returned by `temperatures`.
"""
self.settings_data = self._UNITS_FAHRENHEIT_MSG
def display_celsius(self) -> None:
"""Display temperatures on device in degrees Celsius.
Note: This does not change the units returned by `temperatures`.
"""
self.settings_data = self._UNITS_CELSIUS_MSG
@property
def temperatures(self) -> Optional[Tuple]:
"""Return a tuple of temperatures for all the possible temperature probes on the device.
Temperatures are in degrees Celsius. Unconnected probes return 0.0.
"""
if self._realtime_data_buf is None:
self._realtime_data_buf = bytearray(
self.realtime_data.incoming_packet_length # pylint: disable=no-member
)
data = self._realtime_data_buf
length = self.realtime_data.readinto(data) # pylint: disable=no-member
if length > 0:
return tuple(
struct.unpack_from("<H", data, offset=offset)[0] / 10
for offset in range(0, length, 2)
)
# No data.
return None
@property
def battery_level(self) -> Optional[Tuple[float, float]]:
"""Get current battery level in volts as ``(current_voltage, max_voltage)``.
Results are approximate and may differ from the
actual battery voltage by 0.1v or so.
"""
if self._settings_result_buf is None:
self._settings_result_buf = bytearray(
self.settings_result.incoming_packet_length # pylint: disable=no-member
)
self.settings_data = self._REQUEST_BATTERY_LEVEL_MSG
results = self._settings_result_buf
length = self.settings_result.readinto(results) # pylint: disable=no-member
if length >= 5:
header, current_voltage, max_voltage = struct.unpack_from("<BHH", results)
if header == 0x24:
# Calibration was determined empirically, by comparing
# the returned values with actual measurements of battery voltage,
# on one sample each of two different products.
return (
current_voltage / 2000 - 0.3,
(6550 if max_voltage == 0 else max_voltage) / 2000,
)
# Unexpected response or no data.
return None