BTHome: An open standard for broadcasting sensor data

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2023-03-17 01:30:09

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Many wireless sensors broadcast their data using Bluetooth Low Energy (BLE). Their data is easy to receive, but decoding it can be a challenge. Each manufacturer uses its own format, often tied to its own mobile apps. Integrating all of these sensors into a home-automation system requires a lot of custom decoders, which are generally developed by reverse-engineering the protocols. The goal of the BTHome project is to change this: it offers a standardized format for sensors to broadcast their measurements using BLE. BTHome is supported by the Home Assistant home-automation software and by a few open-firmware and open-hardware projects.

The chances are high that the manufacturer of a BLE device requires the use of a smartphone app to remotely view its data. But, technically, there's no need to use the app. The device advertises its name and some data; anyone with a BLE receiver in the neighborhood is able to pick up those BLE advertisements. What those apps do is to convert the raw data to information such as a temperature or humidity value using a protocol decoder for the proprietary data format.