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#
# Bluetooth LE sensor peripheral
# Copyright (c) 2020 Michael Büsch <m@bues.ch>
#
# This program is free software; you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation; either version 2 of the License, or
# (at your option) any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License along
# with this program; if not, write to the Free Software Foundation, Inc.,
# 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
#
import bluetooth as bt
import ubinascii
from logging import printInfo, printError
from micropython import const
from struct import pack
from util import lim
# org.bluetooth.characteristic.pressure
_PRES_CHAR = (bt.UUID(0x2A6D), bt.FLAG_READ | bt.FLAG_NOTIFY | bt.FLAG_INDICATE,)
# org.bluetooth.characteristic.temperature
_TEMP_CHAR = (bt.UUID(0x2A6E), bt.FLAG_READ | bt.FLAG_NOTIFY | bt.FLAG_INDICATE,)
# org.bluetooth.characteristic.humidity
_HUM_CHAR = (bt.UUID(0x2A6F), bt.FLAG_READ | bt.FLAG_NOTIFY | bt.FLAG_INDICATE,)
# org.bluetooth.characteristic.string
_STR_CHAR = (bt.UUID(0x2A3D), bt.FLAG_READ | bt.FLAG_NOTIFY | bt.FLAG_INDICATE,)
# org.bluetooth.service.environmental_sensing
_ENV_SENSE_UUID = bt.UUID(0x181A)
_ENV_SENSE_SERVICE = (_ENV_SENSE_UUID, (_TEMP_CHAR, _HUM_CHAR, _STR_CHAR, _PRES_CHAR),)
_SERVICES = (_ENV_SENSE_SERVICE,)
_ADV_APPEARANCE_UNKNOWN = const(0)
_ADV_APPEARANCE_GENERIC_THERMOMETER = const(768)
_ADV_TYPE_FLAGS = const(0x01)
_ADV_TYPE_NAME = const(0x09)
_ADV_TYPE_UUID16_COMPLETE = const(0x3)
_ADV_TYPE_UUID32_COMPLETE = const(0x5)
_ADV_TYPE_UUID128_COMPLETE = const(0x7)
_ADV_TYPE_UUID16_MORE = const(0x2)
_ADV_TYPE_UUID32_MORE = const(0x4)
_ADV_TYPE_UUID128_MORE = const(0x6)
_ADV_TYPE_APPEARANCE = const(0x19)
# Interrupt vectors
_IRQ_CENTRAL_CONNECT = const(1)
_IRQ_CENTRAL_DISCONNECT = const(2)
_IRQ_GATTS_WRITE = const(3)
_IRQ_GATTS_READ_REQUEST = const(4)
_IRQ_SCAN_RESULT = const(5)
_IRQ_SCAN_DONE = const(6)
_IRQ_PERIPHERAL_CONNECT = const(7)
_IRQ_PERIPHERAL_DISCONNECT = const(8)
_IRQ_GATTC_SERVICE_RESULT = const(9)
_IRQ_GATTC_SERVICE_DONE = const(10)
_IRQ_GATTC_CHARACTERISTIC_RESULT = const(11)
_IRQ_GATTC_CHARACTERISTIC_DONE = const(12)
_IRQ_GATTC_DESCRIPTOR_RESULT = const(13)
_IRQ_GATTC_DESCRIPTOR_DONE = const(14)
_IRQ_GATTC_READ_RESULT = const(15)
_IRQ_GATTC_READ_DONE = const(16)
_IRQ_GATTC_WRITE_DONE = const(17)
_IRQ_GATTC_NOTIFY = const(18)
_IRQ_GATTC_INDICATE = const(19)
_IRQ_GATTS_INDICATE_DONE = const(20)
class BtSensors(object):
"""Bluetooth LE sensor peripheral.
"""
def __init__(self):
printInfo("Initializing BLE...")
self.__resetCache()
self.__conn = set()
self.__ble = ble = bt.BLE()
ble.active(True)
ble.config(gap_name="envsensors")
addrType, addr = ble.config("mac")
addr = ubinascii.hexlify(addr, ":").decode("ascii")
addrType = {
0: "(public)",
1: "(random)",
2: "(rpa)",
3: "(nrpa)",
}[addrType]
printInfo("BLE MAC:", addr, addrType)
ble.irq(self.__isr)
srv = ble.gatts_register_services(_SERVICES)
self.__hndTemp, self.__hndHumRel, self.__hndHumAbs, self.__hndPres = srv[0]
self.__advPl = self.__advPayload(name="envsensors",
limitedDiscoverable=True,
br_edr=False,
serviceUUIDs=(_ENV_SENSE_UUID,),
appearance=_ADV_APPEARANCE_GENERIC_THERMOMETER)
self.__advertise()
printInfo("BLE initialized.")
@staticmethod
def __advPayload(name,
limitedDiscoverable=False,
br_edr=False,
serviceUUIDs=(),
appearance=_ADV_APPEARANCE_UNKNOWN):
"""Generate advertisement payload.
name: Name string.
limitedDiscoverable: Discoverable for limited period of time.
br_edr: Supports Basic Rate / Enhanced Data Rate.
servicesUUIDs: List of service UUIDs.
appearance: Appearance ID.
"""
pl = bytearray()
def add(advType, value):
pl.extend(pack("BB", len(value) + 1, advType))
pl.extend(value)
flags = 0x01 if limitedDiscoverable else 0x02
flags |= 0x18 if br_edr else 0x04
add(_ADV_TYPE_FLAGS, pack("B", flags))
add(_ADV_TYPE_NAME, name.encode("UTF-8"))
for uuid in serviceUUIDs:
uuid = bytes(uuid)
if len(uuid) == 2:
add(_ADV_TYPE_UUID16_COMPLETE, uuid)
elif len(uuid) == 4:
add(_ADV_TYPE_UUID32_COMPLETE, uuid)
elif len(uuid) == 16:
add(_ADV_TYPE_UUID128_COMPLETE, uuid)
else:
assert False
add(_ADV_TYPE_APPEARANCE, pack("<h", appearance))
return pl
def __isr(self, event, data):
"""Interrupt service routine.
"""
ble = self.__ble
def enter(name):
printInfo("BLE IRQ:", name)
if event == _IRQ_CENTRAL_CONNECT:
enter("_IRQ_CENTRAL_CONNECT")
conn, _, _, = data
self.__conn.add(conn)
self.__resetCache()
elif event == _IRQ_CENTRAL_DISCONNECT:
enter("_IRQ_CENTRAL_DISCONNECT")
conn, _, _, = data
self.__conn.remove(conn)
self.__advertise()
elif event == _IRQ_GATTS_INDICATE_DONE:
conn, handle, status, = data
enter("_IRQ_GATTS_INDICATE_DONE")
else:
printError("BtSensTemp unhandled IRQ: event=%s data=%s" % (
repr(event), repr(data)))
def __advertise(self):
"""Start advertising.
"""
self.__ble.gap_advertise(500000, adv_data=self.__advPl)
def __resetCache(self):
self.__prevTemp = self.__prevHumRel = self.__prevHumAbs = self.__prevPres = None
def __setValue(self, handle, prev, val):
ble = self.__ble
if val != prev:
ble.gatts_write(handle, val)
for conn in self.__conn:
ble.gatts_notify(conn, handle)
ble.gatts_indicate(conn, handle)
return val
def setValues(self, temp, relHum, absHum, pres):
"""Set new sensor values.
temp: Temperature, in degree Celsius.
hum: Relative humidity range 0.0 - 1.0.
absHum: Absolute humidity in g/m3.
pres: Pressure in Pascal.
"""
if temp is not None:
self.__prevTemp = self.__setValue(
self.__hndTemp,
self.__prevTemp,
pack("<h", lim(round(temp * 1e2), -27315, 32767)))
if relHum is not None:
self.__prevHumRel = self.__setValue(
self.__hndHumRel,
self.__prevHumRel,
pack("<H", lim(round(relHum * 1e4), 0, 10000)))
if absHum is not None:
self.__prevHumAbs = self.__setValue(
self.__hndHumAbs,
self.__prevHumAbs,
("Humidity %.1f g/m³" % absHum).encode("UTF-8"))
if pres is not None:
self.__prevPres = self.__setValue(
self.__hndPres,
self.__prevPres,
pack("<I", lim(round(pres * 1e1), 0, 0xFFFFFFFF)))
# vim: ts=4 sw=4 expandtab
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