TL;DR
Nabu Casa has launched the $69 Home Assistant Connect Aux-2, a compact device that adds Bluetooth proxying, audio output and serial connections to Home Assistant setups. A hands-on report found its Bluetooth setup straightforward and used it to reconnect fridge sensors, while audio setup required additional software and equipment. Serial control and some whole-home audio features were not tested or remain in development.
Nabu Casa, the commercial arm of the Open Home Foundation, has launched the $69 Home Assistant Connect Aux-2, a compact device that adds Bluetooth proxying, audio output and serial connections to Home Assistant setups. The box is designed to help users connect equipment that may not have built-in smart-home support, though some of its audio features are still in active development.
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The Aux-2 is about the size of a deck of cards and has 2.4GHz Wi-Fi, Bluetooth and Ethernet, along with USB-A, USB-C, an audio jack, a Grove port for peripherals such as sensors and buttons, and two RS-232 serial ports. Its USB connection can also be used with a Nabu Casa Zigbee or Z-Wave antenna, which may help users whose Home Assistant hub is poorly placed for wireless coverage.
The device is built on ESPHome, an open platform for configuring devices based on ESP boards, and uses existing Home Assistant and ESPHome integrations. A hands-on report described installing firmware through a web browser, adding Wi-Fi details, then completing setup in Home Assistant. Bluetooth proxying took a few clicks; the reviewer then added Govee Bluetooth hygrometers, which appeared in the system and supplied readings from a fridge and freezer.
Audio playback required an amplifier, speakers and Music Assistant, software that runs on Home Assistant hardware and can route music from services and local files to supported outputs. The reviewer said setup took less than half an hour once the speakers were connected to an amplifier. The Aux-2’s serial-control capability, which could connect devices such as TVs, receivers and solar inverters, was not tested in the report.
A new link for smart homes and older gear
The $69 Home Assistant Connect Aux-2 adds Bluetooth, audio and serial connections. Early hands-on results show promise, with some features still untested or in development.
What it connects
One compact device brings several routes for adding equipment to Home Assistant.
Bring in nearby sensors
The reviewer connected Govee hygrometers that supplied fridge and freezer readings.
Add an audio output
Playback worked with an amplifier, speakers and Music Assistant.
Connect older equipment
The ports are intended for devices such as TVs, receivers and solar inverters.
Setup takes extra pieces
The experience depends on the connection you want to use.
Use a web browser, add Wi-Fi details and finish setup in Home Assistant.
The reviewer enabled proxying in a few clicks and added Bluetooth sensors.
Connect speakers to an amplifier and set up Music Assistant for playback.
Ready now and still developing
The listed connections do not guarantee that every use case is ready or compatible.
- Bluetooth sensor setup in one home
- Audio playback with extra hardware and software
- Serial control was not tested
- SendSpin speaker grouping remains in development
- Compatibility varies by device and integration
Connecting Older Equipment to Home Assistant
The Aux-2’s significance is its attempt to make Home Assistant more useful beyond purpose-built smart devices. Bluetooth proxying can bring nearby sensors into a Home Assistant installation without relying on a Bluetooth connection at the main hub. Its USB ports can accommodate radio adapters, while the audio jack and serial ports offer routes to older speakers and equipment that might otherwise sit outside a smart-home setup.
That flexibility may reduce the need for separate bridges or entirely different control systems, but the device is not a universal plug-and-play solution. Users still need compatible integrations and, for audio, additional hardware and software. The hands-on account illustrates both sides: fridge sensors were relatively quick to add, while audio required an amplifier and Music Assistant configuration. How well serial control works across specific devices remains unverified in the report.
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ESPHome Provides the Common Framework
The Aux-2 is part of Nabu Casa’s work to make Home Assistant easier to use, according to the supplied report. Home Assistant is an open-source smart-home platform, while Nabu Casa is the commercial side of the Open Home Foundation. The Aux-2 builds on ESPHome and existing integrations rather than presenting each connection as a separate proprietary system.
The capabilities are at different stages. The report says the serial integration was developed earlier in 2026. Music Assistant and SendSpin, the technologies associated with audio output and grouping, are in active development. SendSpin is described as a whole-home audio standard developed by the Open Home Foundation; the reviewer had not succeeded in grouping speakers using it. These distinctions matter because the hardware’s listed connections do not by themselves confirm that every intended use is ready or works with every device.
“Setting up the Aux-2 was much easier than I expected.”
— The hands-on reviewer
Audio Grouping and Serial Tests Remain Open
The supplied material does not establish how broadly the Aux-2’s serial connections work across brands or models, and the reviewer had not tested serial control. Compatibility with particular TVs, receivers or inverters therefore remains unknown. The report also does not provide independent performance testing, long-term reliability data or battery-life results for the Bluetooth sensors.
SendSpin grouping had not worked for the reviewer, who said it was unclear whether the issue was their setup or the still-developing standard. They also wanted the Aux-2 to appear as an AirPlay or Spotify Connect target, but did not establish whether that was supported or simply required more configuration. These are unresolved observations, not confirmed product limitations.
More Integration Testing Needed
The next useful evidence will come from broader testing of the serial ports, device compatibility and audio features as their software develops. The reviewer said they hoped to try connecting the Aux-2 to an LG television, but the supplied report does not say that test has taken place. It also leaves open whether they will get SendSpin speaker grouping or direct AirPlay and Spotify Connect targeting working.
For prospective buyers, the immediate step is to check whether the integrations and extra equipment needed for their intended setup are available. The reported Bluetooth sensor setup worked in one home, and audio playback was achieved after adding an amplifier and configuring Music Assistant. Those results show possible uses, but they do not establish identical results for every Home Assistant installation.
Key Questions
What is the Home Assistant Connect Aux-2?
It is a $69 multi-function device from Nabu Casa that adds connections including Bluetooth proxying, audio output and RS-232 serial ports to a Home Assistant setup.
Can the Aux-2 connect Bluetooth sensors to Home Assistant?
Yes. The hands-on report enabled Bluetooth proxying and added Govee Bluetooth hygrometers through Home Assistant. That is a reported result from one setup, not a guarantee for every sensor or home.
Can it play music through older speakers?
It can provide an audio connection for an amplifier or powered speakers. In the report, playback also required an amplifier and Music Assistant, which runs on Home Assistant hardware and needs to be configured with sources and outputs.
Does the Aux-2 control TVs and solar inverters?
Its two RS-232 serial ports are intended to connect equipment such as TVs, receivers and solar inverters. The reviewer had not tested serial control, so compatibility and performance with particular devices remain unclear.
Is whole-home audio grouping ready?
The report says SendSpin is still in development and that the reviewer had not managed to group speakers. It does not establish whether the problem was configuration or the developing standard.
Source: theverge.com
