How can I include Manufacturer Data in BLE advertisements?

[DavesCodeMusings]

I've put together a proof of concept DIY Bluetooth Low Energy beacon using an ESP32 and the Arduino C++ platform. What it does is to communicate a battery level in the manufacturer data portion of the BLE advertisement.

I'd like to do the same with MicroPython and aioble.

The idea is to broadcast data at periodic intervals rather than requiring clients to connect and poll a GATT characteristic. That way the ESP32 can spend most of its time in deep sleep, waking up just long enough to send out a few dozen advertisements.

It works great with Arduino BLE. Here's the key part of the code:

byte data[3] = { 0xA3, 0x09, (byte) batteryPercent};
BLE.stopAdvertise();  // Need to re-advertise new data, so stop, update, and start.
BLE.setManufacturerData(data, 3);
BLE.advertise();

The data[] array contains two bytes for the manufacturer's ID (at the mement, I'm using 0x09A3 which is reistered to Arduino SA.) The last byte is the level of the battery charge between 0 and 100.

The problem I'm running across is I cannot find the MicroPython equivalent of BLE.setManufacturerData()

Any suggestions as to how I can set this manufacturer data portion of the BLE Advertisement with MicroPython and aioble?

[Walkline80]

Here's the way to set manufacturer data, but it's not an API way, you have to modify your code, for example:

• Define a constant in examples/bluetooth/ble_advertising.py

  _ADV_TYPE_MANUFACTURER_SPECIFIC_DATA = const(0xFF)

• In the same file, append a new line in advertising_payload function.

  _append(_ADV_TYPE_MANUFACTURER_SPECIFIC_DATA, pack('<2H', 0x09a3, 0x03))

• And then you will got these results
  
  

Please ignore the duplicated items in these screenshots.

[DavesCodeMusings]

With the suggestion from @Walkline80 in mind, I started looking into advertising with aioble. I found this example of a peripheral server

I'm wondering if this bit might be what I'm looking for:

while True:
    connection = await aioble.advertise(
            _ADV_INTERVAL_US,
            name="temp-sense",
            services=[_ENV_SENSE_UUID],
            appearance=_GENERIC_THERMOMETER,
            manufacturer=(0xabcd, b"1234"),
        )

The line with manufacturer=(0xabcd, b"1234"), looks suspiciously like the format used to set manufacturer data: a 16-bit manufacturer ID followed by some arbitrary amount of byte data.

[DavesCodeMusings]

I got it to work by taking the aioble temperature sensor example and adding in manufacturer=(0xabcd, b"1234").

So this...

async def peripheral_task():
    while True:
        async with await aioble.advertise(
            _ADV_INTERVAL_MS,
            name="mpy-temp",
            services=[_ENV_SENSE_UUID],
            appearance=_ADV_APPEARANCE_GENERIC_THERMOMETER,
        ) as connection:
            print("Connection from", connection.device)
            await connection.disconnected(timeout_ms=None)

Became this...

async def peripheral_task():
    while True:
        async with await aioble.advertise(
            _ADV_INTERVAL_MS,
            name="mpy-temp",
            services=[_ENV_SENSE_UUID],
            appearance=_ADV_APPEARANCE_GENERIC_THERMOMETER,
            manufacturer=(0xabcd, b"1234")
        ) as connection:
            print("Connection from", connection.device)
            await connection.disconnected(timeout_ms=None)

And bingo! Manufacturer data showed up in the scan.

[bidrohini]

Have you installed the aioble library from here? https://github.com/micropython/micropython-lib/blob/master/micropython/bluetooth/aioble/README.md

[DavesCodeMusings]

Yes. I actually got this working with aioble. I have the code on my GitHub site, along with a short write up of the process and how to send the advertised readings into Home Assistant using ESPHome's Bluetooth gateway.