openmv/scripts/examples/10-Bluetooth/ble_temperature.py
iabdalkader 0101917e0e scripts/examples: Refactor WiFi and Bluetooth examples.
Unified set of examples for all WiFi/BT modules.
2023-10-28 17:25:57 +02:00

103 lines
3.3 KiB
Python

# This work is licensed under the MIT license.
# Copyright (c) 2013-2023 OpenMV LLC. All rights reserved.
# https://github.com/openmv/openmv/blob/master/LICENSE
#
# This example demonstrates a simple temperature sensor peripheral.
#
# The sensor's local value updates every second, and it will notify
# any connected central every 10 seconds.
import bluetooth
import random
import struct
import time
from ble_advertising import advertising_payload
from machine import LED
from micropython import const
_IRQ_CENTRAL_CONNECT = const(1)
_IRQ_CENTRAL_DISCONNECT = const(2)
_IRQ_GATTS_INDICATE_DONE = const(20)
_FLAG_READ = const(0x0002)
_FLAG_NOTIFY = const(0x0010)
_FLAG_INDICATE = const(0x0020)
# org.bluetooth.service.environmental_sensing
_ENV_SENSE_UUID = bluetooth.UUID(0x181A)
# org.bluetooth.characteristic.temperature
_TEMP_CHAR = (
bluetooth.UUID(0x2A6E),
_FLAG_READ | _FLAG_NOTIFY | _FLAG_INDICATE,
)
_ENV_SENSE_SERVICE = (
_ENV_SENSE_UUID,
(_TEMP_CHAR,),
)
# org.bluetooth.characteristic.gap.appearance.xml
_ADV_APPEARANCE_GENERIC_THERMOMETER = const(768)
class BLETemperature:
def __init__(self, ble, name="mpy-temp"):
self._ble = ble
self._ble.active(True)
self._ble.irq(self._irq)
((self._handle,),) = self._ble.gatts_register_services((_ENV_SENSE_SERVICE,))
self._connections = set()
self._payload = advertising_payload(
name=name,
services=[_ENV_SENSE_UUID],
appearance=_ADV_APPEARANCE_GENERIC_THERMOMETER,
)
self._advertise()
self.led = LED("LED_BLUE")
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)
self.led.on()
elif event == _IRQ_CENTRAL_DISCONNECT:
conn_handle, _, _ = data
self._connections.remove(conn_handle)
# Start advertising again to allow a new connection.
self._advertise()
self.led.off()
elif event == _IRQ_GATTS_INDICATE_DONE:
conn_handle, value_handle, status = data
def set_temperature(self, temp_deg_c, notify=False, indicate=False):
# Data is sint16 in degrees Celsius with a resolution of 0.01 degrees Celsius.
# Write the local value, ready for a central to read.
self._ble.gatts_write(self._handle, struct.pack("<h", int(temp_deg_c * 100)))
if notify or indicate:
for conn_handle in self._connections:
if notify:
# Notify connected centrals.
self._ble.gatts_notify(conn_handle, self._handle)
if indicate:
# Indicate connected centrals.
self._ble.gatts_indicate(conn_handle, self._handle)
def _advertise(self, interval_us=500000):
self._ble.gap_advertise(interval_us, adv_data=self._payload)
if __name__ == "__main__":
ble = bluetooth.BLE()
temp = BLETemperature(ble)
t = 25
i = 0
while True:
# Write every second, notify every 10 seconds.
i = (i + 1) % 10
temp.set_temperature(t, notify=i == 0, indicate=False)
# Random walk the temperature.
t += random.uniform(-0.5, 0.5)
time.sleep_ms(1000)