added bluetooth example code
Alasdair Allan
rodzic
35f9a54463
commit
2cfb06c8f7
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@ -0,0 +1,93 @@
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# Helpers for generating BLE advertising payloads.
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from micropython import const
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import struct
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import bluetooth
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# Advertising payloads are repeated packets of the following form:
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# 1 byte data length (N + 1)
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# 1 byte type (see constants below)
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# N bytes type-specific data
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_ADV_TYPE_FLAGS = const(0x01)
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_ADV_TYPE_NAME = const(0x09)
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_ADV_TYPE_UUID16_COMPLETE = const(0x3)
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_ADV_TYPE_UUID32_COMPLETE = const(0x5)
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_ADV_TYPE_UUID128_COMPLETE = const(0x7)
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_ADV_TYPE_UUID16_MORE = const(0x2)
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_ADV_TYPE_UUID32_MORE = const(0x4)
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_ADV_TYPE_UUID128_MORE = const(0x6)
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_ADV_TYPE_APPEARANCE = const(0x19)
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# Generate a payload to be passed to gap_advertise(adv_data=...).
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def advertising_payload(limited_disc=False, br_edr=False, name=None, services=None, appearance=0):
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payload = bytearray()
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def _append(adv_type, value):
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nonlocal payload
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payload += struct.pack("BB", len(value) + 1, adv_type) + value
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_append(
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_ADV_TYPE_FLAGS,
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struct.pack("B", (0x01 if limited_disc else 0x02) + (0x18 if br_edr else 0x04)),
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)
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if name:
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_append(_ADV_TYPE_NAME, name)
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if services:
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for uuid in services:
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b = bytes(uuid)
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if len(b) == 2:
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_append(_ADV_TYPE_UUID16_COMPLETE, b)
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elif len(b) == 4:
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_append(_ADV_TYPE_UUID32_COMPLETE, b)
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elif len(b) == 16:
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_append(_ADV_TYPE_UUID128_COMPLETE, b)
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# See org.bluetooth.characteristic.gap.appearance.xml
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if appearance:
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_append(_ADV_TYPE_APPEARANCE, struct.pack("<h", appearance))
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return payload
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def decode_field(payload, adv_type):
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i = 0
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result = []
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while i + 1 < len(payload):
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if payload[i + 1] == adv_type:
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result.append(payload[i + 2 : i + payload[i] + 1])
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i += 1 + payload[i]
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return result
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def decode_name(payload):
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n = decode_field(payload, _ADV_TYPE_NAME)
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return str(n[0], "utf-8") if n else ""
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def decode_services(payload):
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services = []
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for u in decode_field(payload, _ADV_TYPE_UUID16_COMPLETE):
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services.append(bluetooth.UUID(struct.unpack("<h", u)[0]))
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for u in decode_field(payload, _ADV_TYPE_UUID32_COMPLETE):
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services.append(bluetooth.UUID(struct.unpack("<d", u)[0]))
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for u in decode_field(payload, _ADV_TYPE_UUID128_COMPLETE):
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services.append(bluetooth.UUID(u))
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return services
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def demo():
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payload = advertising_payload(
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name="micropython",
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services=[bluetooth.UUID(0x181A), bluetooth.UUID("6E400001-B5A3-F393-E0A9-E50E24DCCA9E")],
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)
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print(payload)
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print(decode_name(payload))
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print(decode_services(payload))
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if __name__ == "__main__":
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demo()
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@ -0,0 +1,270 @@
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# This example finds and connects to a BLE temperature sensor (e.g. the one in ble_temperature.py).
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import bluetooth
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import random
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import struct
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import time
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import micropython
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from ble_advertising import decode_services, decode_name
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from micropython import const
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from machine import Pin
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_IRQ_CENTRAL_CONNECT = const(1)
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_IRQ_CENTRAL_DISCONNECT = const(2)
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_IRQ_GATTS_WRITE = const(3)
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_IRQ_GATTS_READ_REQUEST = const(4)
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_IRQ_SCAN_RESULT = const(5)
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_IRQ_SCAN_DONE = const(6)
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_IRQ_PERIPHERAL_CONNECT = const(7)
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_IRQ_PERIPHERAL_DISCONNECT = const(8)
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_IRQ_GATTC_SERVICE_RESULT = const(9)
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_IRQ_GATTC_SERVICE_DONE = const(10)
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_IRQ_GATTC_CHARACTERISTIC_RESULT = const(11)
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_IRQ_GATTC_CHARACTERISTIC_DONE = const(12)
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_IRQ_GATTC_DESCRIPTOR_RESULT = const(13)
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_IRQ_GATTC_DESCRIPTOR_DONE = const(14)
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_IRQ_GATTC_READ_RESULT = const(15)
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_IRQ_GATTC_READ_DONE = const(16)
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_IRQ_GATTC_WRITE_DONE = const(17)
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_IRQ_GATTC_NOTIFY = const(18)
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_IRQ_GATTC_INDICATE = const(19)
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_ADV_IND = const(0x00)
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_ADV_DIRECT_IND = const(0x01)
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_ADV_SCAN_IND = const(0x02)
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_ADV_NONCONN_IND = const(0x03)
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# org.bluetooth.service.environmental_sensing
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_ENV_SENSE_UUID = bluetooth.UUID(0x181A)
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# org.bluetooth.characteristic.temperature
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_TEMP_UUID = bluetooth.UUID(0x2A6E)
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_TEMP_CHAR = (
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_TEMP_UUID,
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bluetooth.FLAG_READ | bluetooth.FLAG_NOTIFY,
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)
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_ENV_SENSE_SERVICE = (
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_ENV_SENSE_UUID,
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(_TEMP_CHAR,),
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)
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class BLETemperatureCentral:
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def __init__(self, ble):
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self._ble = ble
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self._ble.active(True)
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self._ble.irq(self._irq)
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self._reset()
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self._led = Pin('LED', Pin.OUT)
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def _reset(self):
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# Cached name and address from a successful scan.
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self._name = None
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self._addr_type = None
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self._addr = None
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# Cached value (if we have one)
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self._value = None
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# Callbacks for completion of various operations.
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# These reset back to None after being invoked.
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self._scan_callback = None
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self._conn_callback = None
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self._read_callback = None
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# Persistent callback for when new data is notified from the device.
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self._notify_callback = None
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# Connected device.
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self._conn_handle = None
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self._start_handle = None
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self._end_handle = None
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self._value_handle = None
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def _irq(self, event, data):
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if event == _IRQ_SCAN_RESULT:
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addr_type, addr, adv_type, rssi, adv_data = data
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if adv_type in (_ADV_IND, _ADV_DIRECT_IND):
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type_list = decode_services(adv_data)
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if _ENV_SENSE_UUID in type_list:
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# Found a potential device, remember it and stop scanning.
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self._addr_type = addr_type
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self._addr = bytes(addr) # Note: addr buffer is owned by caller so need to copy it.
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self._name = decode_name(adv_data) or "?"
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self._ble.gap_scan(None)
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elif event == _IRQ_SCAN_DONE:
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if self._scan_callback:
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if self._addr:
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# Found a device during the scan (and the scan was explicitly stopped).
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self._scan_callback(self._addr_type, self._addr, self._name)
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self._scan_callback = None
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else:
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# Scan timed out.
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self._scan_callback(None, None, None)
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elif event == _IRQ_PERIPHERAL_CONNECT:
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# Connect successful.
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conn_handle, addr_type, addr = data
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if addr_type == self._addr_type and addr == self._addr:
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self._conn_handle = conn_handle
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self._ble.gattc_discover_services(self._conn_handle)
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elif event == _IRQ_PERIPHERAL_DISCONNECT:
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# Disconnect (either initiated by us or the remote end).
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conn_handle, _, _ = data
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if conn_handle == self._conn_handle:
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# If it was initiated by us, it'll already be reset.
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self._reset()
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elif event == _IRQ_GATTC_SERVICE_RESULT:
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# Connected device returned a service.
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conn_handle, start_handle, end_handle, uuid = data
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if conn_handle == self._conn_handle and uuid == _ENV_SENSE_UUID:
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self._start_handle, self._end_handle = start_handle, end_handle
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elif event == _IRQ_GATTC_SERVICE_DONE:
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# Service query complete.
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if self._start_handle and self._end_handle:
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self._ble.gattc_discover_characteristics(
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self._conn_handle, self._start_handle, self._end_handle
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)
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else:
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print("Failed to find environmental sensing service.")
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elif event == _IRQ_GATTC_CHARACTERISTIC_RESULT:
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# Connected device returned a characteristic.
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conn_handle, def_handle, value_handle, properties, uuid = data
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if conn_handle == self._conn_handle and uuid == _TEMP_UUID:
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self._value_handle = value_handle
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elif event == _IRQ_GATTC_CHARACTERISTIC_DONE:
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# Characteristic query complete.
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if self._value_handle:
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# We've finished connecting and discovering device, fire the connect callback.
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if self._conn_callback:
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self._conn_callback()
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else:
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print("Failed to find temperature characteristic.")
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elif event == _IRQ_GATTC_READ_RESULT:
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# A read completed successfully.
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conn_handle, value_handle, char_data = data
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if conn_handle == self._conn_handle and value_handle == self._value_handle:
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self._update_value(char_data)
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if self._read_callback:
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self._read_callback(self._value)
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self._read_callback = None
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elif event == _IRQ_GATTC_READ_DONE:
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# Read completed (no-op).
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conn_handle, value_handle, status = data
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elif event == _IRQ_GATTC_NOTIFY:
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# The ble_temperature.py demo periodically notifies its value.
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conn_handle, value_handle, notify_data = data
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if conn_handle == self._conn_handle and value_handle == self._value_handle:
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self._update_value(notify_data)
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if self._notify_callback:
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self._notify_callback(self._value)
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# Returns true if we've successfully connected and discovered characteristics.
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def is_connected(self):
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return self._conn_handle is not None and self._value_handle is not None
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# Find a device advertising the environmental sensor service.
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def scan(self, callback=None):
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self._addr_type = None
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self._addr = None
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self._scan_callback = callback
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self._ble.gap_scan(2000, 30000, 30000)
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# Connect to the specified device (otherwise use cached address from a scan).
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def connect(self, addr_type=None, addr=None, callback=None):
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self._addr_type = addr_type or self._addr_type
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self._addr = addr or self._addr
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self._conn_callback = callback
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if self._addr_type is None or self._addr is None:
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return False
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self._ble.gap_connect(self._addr_type, self._addr)
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return True
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# Disconnect from current device.
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def disconnect(self):
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if not self._conn_handle:
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return
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self._ble.gap_disconnect(self._conn_handle)
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self._reset()
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# Issues an (asynchronous) read, will invoke callback with data.
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def read(self, callback):
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if not self.is_connected():
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return
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self._read_callback = callback
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try:
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self._ble.gattc_read(self._conn_handle, self._value_handle)
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except OSError as error:
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print(error)
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# Sets a callback to be invoked when the device notifies us.
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def on_notify(self, callback):
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self._notify_callback = callback
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def _update_value(self, data):
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# Data is sint16 in degrees Celsius with a resolution of 0.01 degrees Celsius.
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try:
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self._value = struct.unpack("<h", data)[0] / 100
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except OSError as error:
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print(error)
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def value(self):
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return self._value
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def sleep_ms_flash_led(self, flash_count, delay_ms):
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self._led.off()
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while(delay_ms > 0):
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for i in range(flash_count):
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self._led.on()
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time.sleep_ms(100)
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self._led.off()
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time.sleep_ms(100)
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delay_ms -= 200
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time.sleep_ms(1000)
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delay_ms -= 1000
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def print_temp(result):
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print("read temp: %.2f degc" % result)
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def demo(ble, central):
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not_found = False
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def on_scan(addr_type, addr, name):
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if addr_type is not None:
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print("Found sensor: %s" % name)
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central.connect()
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else:
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nonlocal not_found
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not_found = True
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print("No sensor found.")
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central.scan(callback=on_scan)
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# Wait for connection...
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while not central.is_connected():
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time.sleep_ms(100)
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if not_found:
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return
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print("Connected")
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# Explicitly issue reads
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while central.is_connected():
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central.read(callback=print_temp)
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sleep_ms_flash_led(central, 2, 2000)
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print("Disconnected")
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if __name__ == "__main__":
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ble = bluetooth.BLE()
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central = BLETemperatureCentral(ble)
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while(True):
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demo(ble, central)
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sleep_ms_flash_led(central, 1, 10000)
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@ -0,0 +1,107 @@
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# This example demonstrates a simple temperature sensor peripheral.
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#
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# The sensor's local value is updated, and it will notify
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# any connected central every 10 seconds.
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import bluetooth
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import random
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import struct
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import time
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import machine
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import ubinascii
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from ble_advertising import advertising_payload
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from micropython import const
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from machine import Pin
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_IRQ_CENTRAL_CONNECT = const(1)
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_IRQ_CENTRAL_DISCONNECT = const(2)
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_IRQ_GATTS_INDICATE_DONE = const(20)
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_FLAG_READ = const(0x0002)
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_FLAG_NOTIFY = const(0x0010)
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_FLAG_INDICATE = const(0x0020)
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# org.bluetooth.service.environmental_sensing
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_ENV_SENSE_UUID = bluetooth.UUID(0x181A)
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# org.bluetooth.characteristic.temperature
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_TEMP_CHAR = (
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bluetooth.UUID(0x2A6E),
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_FLAG_READ | _FLAG_NOTIFY | _FLAG_INDICATE,
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)
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_ENV_SENSE_SERVICE = (
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_ENV_SENSE_UUID,
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(_TEMP_CHAR,),
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)
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# org.bluetooth.characteristic.gap.appearance.xml
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_ADV_APPEARANCE_GENERIC_THERMOMETER = const(768)
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class BLETemperature:
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def __init__(self, ble, name=""):
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self._sensor_temp = machine.ADC(4)
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self._ble = ble
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self._ble.active(True)
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self._ble.irq(self._irq)
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((self._handle,),) = self._ble.gatts_register_services((_ENV_SENSE_SERVICE,))
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self._connections = set()
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if len(name) == 0:
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name = 'Pico %s' % ubinascii.hexlify(self._ble.config('mac')[1],':').decode().upper()
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print('Sensor name %s' % name)
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self._payload = advertising_payload(
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name=name, services=[_ENV_SENSE_UUID]
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)
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self._advertise()
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def _irq(self, event, data):
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# Track connections so we can send notifications.
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if event == _IRQ_CENTRAL_CONNECT:
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conn_handle, _, _ = data
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self._connections.add(conn_handle)
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elif event == _IRQ_CENTRAL_DISCONNECT:
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conn_handle, _, _ = data
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self._connections.remove(conn_handle)
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# Start advertising again to allow a new connection.
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self._advertise()
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elif event == _IRQ_GATTS_INDICATE_DONE:
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conn_handle, value_handle, status = data
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def update_temperature(self, notify=False, indicate=False):
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# Write the local value, ready for a central to read.
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temp_deg_c = self._get_temp()
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print("write temp %.2f degc" % temp_deg_c);
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self._ble.gatts_write(self._handle, struct.pack("<h", int(temp_deg_c * 100)))
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if notify or indicate:
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for conn_handle in self._connections:
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if notify:
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# Notify connected centrals.
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self._ble.gatts_notify(conn_handle, self._handle)
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if indicate:
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# Indicate connected centrals.
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self._ble.gatts_indicate(conn_handle, self._handle)
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def _advertise(self, interval_us=500000):
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self._ble.gap_advertise(interval_us, adv_data=self._payload)
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# ref https://github.com/raspberrypi/pico-micropython-examples/blob/master/adc/temperature.py
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def _get_temp(self):
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conversion_factor = 3.3 / (65535)
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reading = self._sensor_temp.read_u16() * conversion_factor
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# The temperature sensor measures the Vbe voltage of a biased bipolar diode, connected to the fifth ADC channel
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# Typically, Vbe = 0.706V at 27 degrees C, with a slope of -1.721mV (0.001721) per degree.
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return 27 - (reading - 0.706) / 0.001721
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def demo():
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ble = bluetooth.BLE()
|
||||
temp = BLETemperature(ble)
|
||||
counter = 0
|
||||
led = Pin('LED', Pin.OUT)
|
||||
while True:
|
||||
if counter % 10 == 0:
|
||||
temp.update_temperature(notify=True, indicate=False)
|
||||
led.toggle()
|
||||
time.sleep_ms(1000)
|
||||
counter += 1
|
||||
|
||||
if __name__ == "__main__":
|
||||
demo()
|
||||
Ładowanie…
Reference in New Issue