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. A hands-on test found setup straightforward and used it to connect Bluetooth temperature sensors and play music through older speakers, while serial control and cross-protocol speaker grouping remain untested or in development.
Nabu Casa, the commercial arm of the Open Home Foundation, has launched the $69 Home Assistant Connect Aux-2, a small device that adds connections for Bluetooth, audio equipment and serial-controlled hardware to a Home Assistant setup. In a hands-on report for The Verge, the reviewer said it was straightforward to configure and used it to connect Bluetooth temperature sensors and play music through in-wall speakers.
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About the size of a deck of cards, the Aux-2 includes 2.4GHz Wi-Fi, Bluetooth, Ethernet, USB-A and USB-C, plus an audio jack, a Grove port for peripherals and two RS-232 serial ports. A USB port can also take a Nabu Casa Zigbee or Z-Wave antenna, allowing users to position that radio separately from their Home Assistant hub.
The reviewer tested the device for a couple of days. After installing firmware through a browser and entering Wi-Fi details, they plugged it in near their media equipment and completed setup through the Home Assistant interface. The ESPHome integration discovered the Aux-2 and presented options for enabling its capabilities.
For a fridge-monitoring setup, the reviewer enabled Bluetooth proxying, added the Govee Bluetooth integration and inserted batteries into the sensors. The sensors appeared in Home Assistant and, according to the report, kept their connection through three walls and a refrigerator. The reviewer also connected an amplifier to in-wall speakers and set up Music Assistant, which took less than half an hour overall. They did not test serial control.
Adding Connections Without Replacing Devices
The Aux-2 is aimed at a familiar smart-home problem: useful devices and equipment may not have built-in network features, or may be difficult to reach from the main Home Assistant hub. Its Bluetooth proxy can bring nearby Bluetooth devices into Home Assistant, while USB support for Zigbee or Z-Wave radios may help users place those connections where reception is better.
Audio and serial connections broaden the possible uses beyond sensors. The device can feed audio to an amplifier or powered speakers, and its serial ports are intended for controlling compatible equipment such as TVs, AV receivers and solar inverters. That could let Home Assistant users connect older or specialized hardware without replacing it. The hands-on test, however, establishes only that Bluetooth sensing and audio playback worked in this setup; it does not verify the full range of supported devices or serial-control use cases.
The price and setup experience matter because Home Assistant can require users to assemble integrations and hardware themselves. The reviewer described the Aux-2 setup as easier than expected. That is an individual test, not evidence that every installation will be equally simple: results can depend on the equipment, integrations and network involved.
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ESPHome and Existing Integrations
The Aux-2 is based on ESPHome, an open platform for creating devices using ESP boards. Rather than requiring a separate system for each function, it relies on existing Home Assistant and ESPHome integrations. Nabu Casa is the commercial side of the Open Home Foundation, which runs Home Assistant.
The reviewer tested the Aux-2 against two needs in their own home: getting reliable readings from Bluetooth temperature sensors in a garage fridge and putting previously unused in-wall speakers to work. Their earlier fridge-monitoring sensors had connection and battery-life problems, while the speaker installation had remained unused as the reviewer weighed amplifier options. These are examples from one home, not formal product tests across different devices or households.
The software behind the audio features is at different stages. Music Assistant runs on Home Assistant hardware and can play from services including Spotify, YouTube Music and local files to configured outputs such as Sonos, AirPlay and Google Cast. Sendspin, a whole-home audio standard developed by the Open Home Foundation, is still in development, according to the report. The serial integration was developed earlier in 2026.
““unsurprisingly useful and surprisingly easy to set up.””
— The Verge reviewer
Serial Control and Audio Grouping Untested
The reviewer had not yet tested the Aux-2’s RS-232 serial control, so the report does not confirm how well it works with particular TVs, receivers, solar inverters or other equipment. Compatibility and setup requirements for those devices remain unclear from the hands-on test.
The reviewer also could not get Sendspin grouping across different speaker protocols working during the test. Sendspin is still in development, and the report does not establish whether the problem came from the setup or the software. The reviewer had not yet configured the Aux-2 as an AirPlay or Spotify Connect target, either. Those functions were not confirmed as working in the test.
Further Testing Will Clarify Compatibility
The next useful test would be to connect the Aux-2 to serial-controlled equipment and document which devices work, what configuration they require and how reliably commands are handled. The reviewer also said they would like to test the audio setup further, including Sendspin grouping and making the Aux-2 available as an AirPlay or Spotify Connect target.
For now, the reported results are limited to one Home Assistant installation: Bluetooth sensors were detected and stayed connected in the reviewer’s fridge setup, and Music Assistant played music through the newly connected in-wall speakers. Broader device compatibility, the status of Sendspin as it develops and the effort required for different configurations remain open questions.
Key Questions
What is the Home Assistant Connect Aux-2?
It is a $69 device from Nabu Casa that adds Bluetooth, audio and serial connections to Home Assistant, alongside Wi-Fi, Ethernet, USB and a Grove port.
What did the hands-on test confirm?
The reviewer set up Bluetooth proxying for Govee temperature and humidity sensors, which appeared in Home Assistant and reportedly stayed connected through three walls and a refrigerator. The reviewer also played music through in-wall speakers using an amplifier and Music Assistant.
Can the Aux-2 control a TV or solar inverter?
Its two RS-232 serial ports are intended to connect compatible equipment, including TVs, AV receivers and solar inverters. The reviewer had not tested serial control, so working compatibility with specific devices was not established.
Does it support grouped audio across different speaker systems?
The report says Sendspin is intended to support grouping speakers across protocols under certain conditions, but the standard is still in development. The reviewer had not got grouping working during testing.
How difficult was setup?
The reviewer installed firmware through a browser, entered Wi-Fi details and completed the remaining setup in Home Assistant. They described the process as easier than expected, but setup may vary with a user’s hardware and integrations.
Source: theverge.com
