feat(ble): Add BLE beacon advertising example with OLED display.

BLE/BLE_Beacon/BLE_Beacon_temperature.py

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+"""BLE beacon advertising example using aioble and SSD1327 OLED.
+
+Broadcasts a BLE advertisement containing the board name and a live
+temperature reading from the WSEN-PADS sensor. The beacon is visible
+from any BLE scanner app (nRF Connect, LightBlue, etc.).
+
+Hardware:
+    - STM32WB55 BLE radio
+    - SSD1327 128x128 OLED display (round)
+    - WSEN-PADS pressure + temperature sensor
+
+BLE payload:
+    - Complete Local Name: "STeaMi-XXXX" (last 2 bytes of MAC address)
+    - Manufacturer Specific Data: temperature as int16 (x100, in 0.01 C)
+"""
+
+import bluetooth
+import struct
+import uasyncio as asyncio
+
+import aioble
+import ssd1327
+from machine import I2C, SPI, Pin
+from steami_screen import GRAY, GREEN, LIGHT, Screen, SSD1327Display, WHITE
+from wsen_pads import WSEN_PADS
+
+# === BLE setup ===
+ble = bluetooth.BLE()
+ble.active(True)
+
+mac_bytes = ble.config("mac")[1]
+mac_suffix = "".join(f"{b:02X}" for b in mac_bytes[-2:])
+DEVICE_NAME = f"STeaMi-{mac_suffix}"
+print("Device name:", DEVICE_NAME)
+
+# === Display ===
+spi = SPI(1)
+dc = Pin("DATA_COMMAND_DISPLAY")
+res = Pin("RST_DISPLAY")
+cs = Pin("CS_DISPLAY")
+display = SSD1327Display(ssd1327.WS_OLED_128X128_SPI(spi, dc, res, cs))
+screen = Screen(display)
+
+# === Sensor ===
+i2c = I2C(1)
+pads = WSEN_PADS(i2c)
+
+# === BLE parameters ===
+ADV_INTERVAL_US = 200_000  # 200 ms between advertisements
+ADV_TIMEOUT_MS = 500  # advertise for 500 ms per cycle
+SENSOR_INTERVAL_MS = 1000  # read sensor every 1 second
+
+# === Shared state ===
+temperature = 0.0
+
+
+def build_adv_payload(name, temp_raw):
+    """Build a BLE advertising payload.
+
+    Contains:
+        - Complete Local Name (type 0x09)
+        - Manufacturer Specific Data (type 0xFF): int16 temperature x100
+    """
+    payload = bytearray()
+
+    # Complete Local Name
+    name_bytes = name.encode()
+    payload += bytes((len(name_bytes) + 1, 0x09)) + name_bytes
+
+    # Manufacturer Specific Data: temperature encoded as int16 (x100)
+    man_data = struct.pack("h", temp_raw)
+    payload += bytes((len(man_data) + 1, 0xFF)) + man_data
+
+    return payload
+
+
+async def sensor_task():
+    """Read temperature from WSEN-PADS every second."""
+    global temperature
+    while True:
+        try:
+            temperature = pads.temperature()
+        except Exception as e:
+            print("Sensor error:", e)
+        await asyncio.sleep_ms(SENSOR_INTERVAL_MS)
+
+
+async def ble_task():
+    """Advertise BLE beacon with device name and temperature."""
+    while True:
+        # Encode temperature as int16 (multiply by 100 to keep 2 decimals)
+        temp_raw = int(temperature * 100)
+        adv_payload = build_adv_payload(DEVICE_NAME, temp_raw)
+
+        try:
+            await aioble.advertise(
+                interval_us=ADV_INTERVAL_US,
+                adv_data=adv_payload,
+                connectable=False,
+                timeout_ms=ADV_TIMEOUT_MS,
+            )
+        except asyncio.TimeoutError:
+            pass  # Normal: non-connectable advertisement timeout
+
+        await asyncio.sleep_ms(100)
+
+
+async def display_task():
+    """Update OLED display with current beacon state."""
+    while True:
+        screen.clear()
+        screen.title("BLE BEACON")
+        screen.value(f"{temperature:.1f}", unit="C")
+        screen.subtitle(DEVICE_NAME, "Advertising...")
+        screen.show()
+        await asyncio.sleep_ms(500)
+
+
+async def main():
+    await asyncio.gather(
+        sensor_task(),
+        ble_task(),
+        display_task(),
+    )
+
+
+asyncio.run(main())