TL;DR
Nabu Casa has launched the $69 Home Assistant Connect Aux-2, a compact device that adds connections including Bluetooth, USB, audio and serial to Home Assistant. A hands-on account reports easy setup for Bluetooth sensors and music playback, while serial control and cross-platform 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 compact device that adds ways to connect Bluetooth devices, audio equipment and serial-controlled hardware to Home Assistant. In a hands-on test, Bluetooth sensors and music playback worked after setup, while serial control had not yet been tested.
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The Aux-2 is roughly the size of a deck of cards and includes 2.4GHz Wi-Fi, Bluetooth, Ethernet, USB-A and USB-C, an audio jack that supports digital or analog output, a Grove port for peripherals such as sensors and buttons, and two RS-232 serial ports. Its USB connection can also host a Nabu Casa Zigbee or Z-Wave antenna, which may help when a Home Assistant hub is poorly placed for wireless coverage.
Here are five ways to put those connections to use. First, bridge Bluetooth sensors into Home Assistant: the reviewer used the Aux-2 to connect Govee temperature and humidity sensors monitoring a garage refrigerator and freezer. The sensors appeared after Bluetooth proxying was enabled and the Govee integration was added. In that home, they maintained their connection through three walls and a fridge.
Second, add Zigbee or Z-Wave coverage by plugging a compatible Nabu Casa antenna into USB and placing the Aux-2 where it can reach devices more reliably. Third, use its serial ports to control or communicate with equipment such as TVs, receivers or solar inverters. That use is supported as a capability, but the reviewer had not tested it. Fourth, connect an amplifier or powered speakers to the audio jack to play music through older audio equipment. Fifth, attach Grove peripherals such as sensors, buttons or LEDs for additional Home Assistant projects; the source lists the port’s purpose but does not describe a specific tested Grove setup.
5 ways to use Home Assistant’s Aux-2
Nabu Casa’s $69 device adds connections for sensors, audio and existing equipment. Two uses worked in one hands-on test; others still need testing or development.
Connecting Older Gear to Home Assistant
The Aux-2’s appeal is not a new smart-home platform; it is a way to bring devices that already exist into one. A Bluetooth proxy can make otherwise separate sensors available to Home Assistant, while USB, serial and audio connections can extend the system to equipment that does not have a convenient direct connection.
That flexibility may reduce the need to replace working equipment or buy a separate bridge for every use. But its practical value depends on compatible integrations and setup. The reported refrigerator-monitoring and music examples worked for one reviewer; they do not establish that every device or setup will work the same way.
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Built on ESPHome Integrations
The Aux-2 is based on ESPHome, an open platform for building and connecting devices based on ESP boards. Its functions use existing Home Assistant and ESPHome integrations rather than a single proprietary control system. The reviewer connected the Aux-2 to a computer by USB-C, installed firmware through a browser, added Wi-Fi details, then completed setup in Home Assistant using an ESPHome setup flow.
Audio uses Music Assistant, which runs on Home Assistant hardware and can play from configured services and to configured outputs. The reviewer said configuring it and connecting an amplifier took less than half an hour. The serial integration was developed earlier in 2026, while Music Assistant and SendSpin, the software associated with the audio feature, were described as being in active development.
“Setting up the Aux-2 was much easier than I expected.”
— The reviewer
Serial Control and Audio Grouping
The reviewer had not tested the serial ports, so the account does not establish how easily specific TVs, receivers or solar inverters can be controlled, or which models are compatible. The Aux-2’s listed ports and intended uses should not be taken as confirmation that every device will work with it.
Cross-platform speaker grouping is also unsettled. SendSpin is described as a whole-home audio standard in development, and the reviewer had not succeeded in grouping speakers from different protocols. The reviewer also had not established whether the Aux-2 could appear directly as an AirPlay or Spotify Connect target. Pricing is given as $69, but the source does not provide full availability, regional pricing or a release schedule.
Testing Compatibility in More Setups
The next useful test is whether serial control works with specific equipment and how much configuration those integrations require. Music Assistant and SendSpin development may also change the available audio options over time. Buyers should check current Home Assistant and ESPHome documentation for supported integrations and device requirements before choosing the Aux-2 for a particular setup.
For now, the reported results establish working Bluetooth sensor access and music playback in one home, not universal compatibility. Further testing and product details would clarify how well the remaining functions work across different devices.
Key Questions
What is the Home Assistant Connect Aux-2?
It is a $69 Nabu Casa device with Bluetooth, Wi-Fi, Ethernet, USB, audio, Grove and serial connections intended to connect more equipment to Home Assistant.
Can the Aux-2 connect Bluetooth sensors to Home Assistant?
Yes. In the reported test, enabling Bluetooth proxying and adding the Govee integration brought Bluetooth temperature and humidity sensors into Home Assistant. Results may vary by location and device.
Can it play music through older speakers?
The audio jack can connect to an amplifier or powered speakers. The reviewer used Music Assistant to play music through in-wall speakers after connecting an amplifier.
What does the serial connection support?
The Aux-2 has two RS-232 ports intended for equipment such as TVs, receivers and solar inverters. The reviewer had not tested serial control, and compatibility with specific models remains unclear.
Does the Aux-2 group speakers across different systems?
SendSpin is intended to support grouping speakers from different protocols under certain conditions, but it is still in development. The reviewer had not gotten that setup working.
Source: theverge.com
