PiCow Bluetooth communication - integers

# Save as BLE_server.py
# Modified to send random integers much faster
# Tony Goodhew 19th June 2023
# This is quick and dirty. It uses the Environmental Sensing and Temperature UUIDs
import bluetooth
import random
import struct
import time
import machine
import ubinascii
from ble_advertising import advertising_payload
from micropython import const
from machine import Pin
import random ############################# EXTRA LINE ###########
_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=""):
        self._sensor_temp = machine.ADC(4)
        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()
        if len(name) == 0:
            name = 'Pico %s' % ubinascii.hexlify(self._ble.config('mac')[1],':').decode().upper()
        print('Sensor name %s' % name)
        self._payload = advertising_payload(
            name=name, services=[_ENV_SENSE_UUID]
        )
        self._advertise()

    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)
        elif event == _IRQ_CENTRAL_DISCONNECT:
            conn_handle, _, _ = data
            self._connections.remove(conn_handle)
            # Start advertising again to allow a new connection.
            self._advertise()
        elif event == _IRQ_GATTS_INDICATE_DONE:
            conn_handle, value_handle, status = data

    def update_temperature(self, notify=False, indicate=False):
        # Write the local value, ready for a central to read.
        data = random.randint(0,9999)   # Generate a random number
#        print("write temp %.2f degc" % temp_deg_c);
        print(data,"Current value being sent");
        self._ble.gatts_write(self._handle, struct.pack("<h", data)) ###
        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=5000):  # was 500000
        self._ble.gap_advertise(interval_us, adv_data=self._payload)
'''
    def _get_temp(self):   #################### Modified here ##########
        x = random.randint(0,9999)

        return float(x)
'''

def demo():
    ble = bluetooth.BLE()
    temp = BLETemperature(ble)
    counter = 0
    led = Pin('LED', Pin.OUT)
    while True:
        if counter % 2 == 0:
            temp.update_temperature(notify=True, indicate=False)
        led.toggle()
        time.sleep_ms(100)
        counter += 1

if __name__ == "__main__":
    demo()


############ SECOND PROGRAM BELOW ############

# Save as BLE_reader.py
# Finds and connects to a BLE temperature sensor but reads integers
# Modified to receive random integers much faster
# Tony Goodhew 19th June 2023
import bluetooth
import random
import struct
import time
import micropython
from ble_advertising import decode_services, decode_name
from micropython import const
from machine import Pin

_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)

_ADV_IND = const(0x00)
_ADV_DIRECT_IND = const(0x01)
_ADV_SCAN_IND = const(0x02)
_ADV_NONCONN_IND = const(0x03)

# org.bluetooth.service.environmental_sensing
_ENV_SENSE_UUID = bluetooth.UUID(0x181A)
# org.bluetooth.characteristic.temperature
_TEMP_UUID = bluetooth.UUID(0x2A6E)
_TEMP_CHAR = (
    _TEMP_UUID,
    bluetooth.FLAG_READ | bluetooth.FLAG_NOTIFY,
)
_ENV_SENSE_SERVICE = (
    _ENV_SENSE_UUID,
    (_TEMP_CHAR,),
)

class BLETemperatureCentral:
    def __init__(self, ble):
        self._ble = ble
        self._ble.active(True)
        self._ble.irq(self._irq)
        self._reset()
        self._led = Pin('LED', Pin.OUT)

    def _reset(self):
        # Cached name and address from a successful scan.
        self._name = None
        self._addr_type = None
        self._addr = None

        # Cached value (if we have one)
        self._value = None

        # Callbacks for completion of various operations.
        # These reset back to None after being invoked.
        self._scan_callback = None
        self._conn_callback = None
        self._read_callback = None

        # Persistent callback for when new data is notified from the device.
        self._notify_callback = None

        # Connected device.
        self._conn_handle = None
        self._start_handle = None
        self._end_handle = None
        self._value_handle = None

    def _irq(self, event, data):
        if event == _IRQ_SCAN_RESULT:
            addr_type, addr, adv_type, rssi, adv_data = data
            if adv_type in (_ADV_IND, _ADV_DIRECT_IND):
                type_list = decode_services(adv_data)
                if _ENV_SENSE_UUID in type_list:
                    # Found a potential device, remember it and stop scanning.
                    self._addr_type = addr_type
                    self._addr = bytes(addr) # Note: addr buffer is owned by caller so need to copy it.
                    self._name = decode_name(adv_data) or "?"
                    self._ble.gap_scan(None)

        elif event == _IRQ_SCAN_DONE:
            if self._scan_callback:
                if self._addr:
                    # Found a device during the scan (and the scan was explicitly stopped).
                    self._scan_callback(self._addr_type, self._addr, self._name)
                    self._scan_callback = None
                else:
                    # Scan timed out.
                    self._scan_callback(None, None, None)

        elif event == _IRQ_PERIPHERAL_CONNECT:
            # Connect successful.
            conn_handle, addr_type, addr = data
            if addr_type == self._addr_type and addr == self._addr:
                self._conn_handle = conn_handle
                self._ble.gattc_discover_services(self._conn_handle)

        elif event == _IRQ_PERIPHERAL_DISCONNECT:
            # Disconnect (either initiated by us or the remote end).
            conn_handle, _, _ = data
            if conn_handle == self._conn_handle:
                # If it was initiated by us, it'll already be reset.
                self._reset()

        elif event == _IRQ_GATTC_SERVICE_RESULT:
            # Connected device returned a service.
            conn_handle, start_handle, end_handle, uuid = data
            if conn_handle == self._conn_handle and uuid == _ENV_SENSE_UUID:
                self._start_handle, self._end_handle = start_handle, end_handle

        elif event == _IRQ_GATTC_SERVICE_DONE:
            # Service query complete.
            if self._start_handle and self._end_handle:
                self._ble.gattc_discover_characteristics(
                    self._conn_handle, self._start_handle, self._end_handle)

            else:
                print("Failed to find environmental sensing service.")

        elif event == _IRQ_GATTC_CHARACTERISTIC_RESULT:
            # Connected device returned a characteristic.
            conn_handle, def_handle, value_handle, properties, uuid = data
            if conn_handle == self._conn_handle and uuid == _TEMP_UUID:
                self._value_handle = value_handle

        elif event == _IRQ_GATTC_CHARACTERISTIC_DONE:
            # Characteristic query complete.
            if self._value_handle:
                # We've finished connecting and discovering device, fire the connect callback.
                if self._conn_callback:
                    self._conn_callback()
            else:
                print("Failed to find temperature characteristic.")

        elif event == _IRQ_GATTC_READ_RESULT:
            # A read completed successfully.
            conn_handle, value_handle, char_data = data
            if conn_handle == self._conn_handle and value_handle == self._value_handle:
                self._update_value(char_data)
                if self._read_callback:
                    self._read_callback(self._value)
                    self._read_callback = None

        elif event == _IRQ_GATTC_READ_DONE:
            # Read completed (no-op).
            conn_handle, value_handle, status = data

        elif event == _IRQ_GATTC_NOTIFY:
            # The ble_temperature.py demo periodically notifies its value.
            conn_handle, value_handle, notify_data = data
            if conn_handle == self._conn_handle and value_handle == self._value_handle:
                self._update_value(notify_data)
                if self._notify_callback:
                    self._notify_callback(self._value)

        # Returns true if we've successfully connected and discovered characteristics.
    def is_connected(self):
        return self._conn_handle is not None and self._value_handle is not None

    # Find a device advertising the environmental sensor service.
    def scan(self, callback=None):
        self._addr_type = None
        self._addr = None
        self._scan_callback = callback
        self._ble.gap_scan(2000, 30000, 30000)

    # Connect to the specified device (otherwise use cached address from a scan).
    def connect(self, addr_type=None, addr=None, callback=None):
        self._addr_type = addr_type or self._addr_type
        self._addr = addr or self._addr
        self._conn_callback = callback
        if self._addr_type is None or self._addr is None:
            return False
        self._ble.gap_connect(self._addr_type, self._addr)
        return True

    # Disconnect from current device.
    def disconnect(self):
        if not self._conn_handle:
            return
        self._ble.gap_disconnect(self._conn_handle)
        self._reset()

    # Issues an (asynchronous) read, will invoke callback with data.
    def read(self, callback):
        if not self.is_connected():
            return
        self._read_callback = callback
        try:
            self._ble.gattc_read(self._conn_handle, self._value_handle)
        except OSError as error:
            print(error)

    # Sets a callback to be invoked when the device notifies us.
    def on_notify(self, callback):
        self._notify_callback = callback

    def _update_value(self, data):
    # Data is sint16 in degrees Celsius with a resolution of 0.01 degrees Celsius.
        try:
            self._value = struct.unpack("<h", data)[0]   ####### Modified
        except OSError as error:
            print(error)

    def value(self):
        return self._value

def sleep_ms_flash_led(self, flash_count, delay_ms):
    self._led.off()
    while(delay_ms > 0):
        for i in range(flash_count):
            self._led.on()
            time.sleep_ms(100)
            self._led.off()
            time.sleep_ms(100)
            delay_ms -= 200
        time.sleep_ms(10) # was 1000
        delay_ms -= 1000

def print_temp(result):
    print(result, "Received")  ### Modified

def demo(ble, central):
    not_found = False

    def on_scan(addr_type, addr, name):
        if addr_type is not None:
            print("Found sensor: %s" % name)
            central.connect()
        else:
            nonlocal not_found
            not_found = True
            print("No sensor found.")

    central.scan(callback=on_scan)

    # Wait for connection...
    while not central.is_connected():
        time.sleep_ms(100)
        if not_found:
            return

    print("Connected")

    # Explicitly issue reads
    while central.is_connected():
        central.read(callback=print_temp)
        sleep_ms_flash_led(central, 1, 2) ## was 2000

    print("Disconnected")

if __name__ == "__main__":
    ble = bluetooth.BLE()
    central = BLETemperatureCentral(ble)
    while(True):
        demo(ble, central)
        sleep_ms_flash_led(central, 1, 10000)