Support for LYWSD03MMC with pvvx's bthome.io advertising format?

[Heiko-L]

There is a new advertising format in town:

https://bthome.io/

It integrates directly with home assistant so I could uninstall Passive BLE monitor integration for sensors in range of my raspberry pi.

I would like to use this format with pvvx flashed xiaomi devices

https://github.com/pvvx/ATC_MiThermometer#readme

[koenvervloesem]

A full BTHome decoder would probably be a bit much (see a previous discussion), but if you're targeting specific devices that implement a fixed subset of BTHome that should be possible. For instance, I recently added a decoder for the ShellyBLU Button1, which uses the BTHome format to advertise a button press type, battery percentage and packet ID.

[Heiko-L]

Thank you
I changed the title accordingly

[koenvervloesem]

Can you show an example of the advertised data by this device?

[Heiko-L]

I will flash a sensor with the new firmware and dump it.
Is it also possible to process encrypted data (bthome supports AES with pre-shared key https://bthome.io/encryption/)?

[koenvervloesem]

Encryption is not supported yet, we'll need to look into it how to implement that first.

[DigiH]

Hi @Heiko-L

While I generally understand your request for BTHome decoding in OpenMQTTGateway, and with your comment

It integrates directly with home assistant so I could uninstall Passive BLE monitor integration for sensors in range of my raspberry pi.

Using the native PVVX protocol should already be supported by the HA integration, for devices near your RPi Bluetooth adapter, as well as with OpenMQTTGateway for devices further away.

So apart from a protocol fondness the scenario should already be working nicely.

[Heiko-L]

Using the native PVVX protocol should already be supported by the HA integration

Tell me more. I was only able to add my pvvx flashed LYWSD03MMCs with pvvx advertisements via HACS->Passive BLE monitor.

[DigiH]

Admittedly, I do not have any LYWSD03MMCs, hence the should in the above statement ;) but from what I understood with the shift from ble-monitor to the native HA BLE integration, was that the same format decodings would be ported over, so that the xiaomi-ble part would also be able to decode the Xiaomi (MiBeacon), ATC1441 and PVVX native protocols along with the BTHome protocol.

Please correct me if this is not the case, as I will then have to totally reevaluate my understanding of the native HA BLE integration.

[Heiko-L]

If I try to add the Xiaomi->Xiaomi BLE or BTHome integration I get "No devices found on the network".
Or do I have to disable Passive BLE monitor first?

[DigiH]

I'm afraid I really am not sure. Or could be really that the native HA BLE integration only does support BTHome, which would be a surprise for me. Also then the Xiaomi BLE page also only seem to talk about the MiBeacon protocol, not even BTHome. Even more confusing now :(

[DigiH]

This seems to indicate that it should work with the PVVX protocol with the Xiaomi HA integration, but

… it works but not as well as Passive BLE Monitor. If your BLE signal strength is low you get gaps in your data, rather than using the previous temperature the sensors show “unavailable” or similar. I have both running, but I only use the data from Passive BLE Monitor, which also provide signal strength.
…
As of HA 2022.09 and later, just wait for BTHome to discover the sensors, give you a notification, at which point you can add them to HA.

https://community.home-assistant.io/t/home-asssistant-xiaomi-mijia-lywsd03mmc-temperature-and-humidity-sensor-tutorial-september-2022/456403

So now being mid 2023 I would assume it should still work as described, and possibly has been improved since then.

[Heiko-L]

You are right- I also read a thread where Ernst79 stated that he implemented the ATC and pvvx format in BTHome, so my underlying problem seems to be a non working Bluetooth/BTHome integration so I opened an issue in home assistant for this.

I hope I have the time to get a "BTHome" dump of a LYWSD03MMC this weekend...

[DigiH]

I'm also very curious as to what the issue might be, and the resolution.

Nonetheless, as @koenvervloesem pointed out above, the BTHome protocol and decryption is something we're also looking into for the future.

[Heiko-L]

I'm also very curious as to what the issue might be, and the resolution.

pvvx advertisement format seems to be dropped, as soon I flashed the LYWSD03MMC to use BTHome advertisements BTHome created a new device in HA.

Can you show an example of the advertised data by this device?

It is using the legacy format: https://bthome.io/v1/ with packet ids:

020106 11 161C18 020045 23024107 0303C316 020157 0B 094154435F43656C6C6172
020106 0D 161C18 020044 021001 030C000B 0B 094154435F43656C6C6172