Home Assistant AUX-2: $69 Box Makes Old Gear Smart

Nabu Casa has launched the Home Assistant Connect AUX-2, a $69 smart home multi-tool designed to give the devices you already own a second life. The compact box went on sale worldwide on November 11, 2026, priced at $69 in the US and €59 in Europe, and it tackles a problem every long-time smart home owner knows well: perfectly good speakers, amplifiers, and TVs that were never built to be smart.

“A smart home multi-tool that makes the devices you already own smart” is how Nabu Casa describes it. Rather than replacing old gear, the AUX-2 connects it to Home Assistant, the open-source smart home platform, using local control that keeps working even if a cloud service disappears.

What the AUX-2 actually does

About the size of a deck of cards at 106 x 63 x 25 mm, the AUX-2 packs a surprising range of connections into a small enclosure: 2.4GHz Wi-Fi, Bluetooth, Ethernet with Power over Ethernet support, a USB-A port, USB-C, a digital and analog audio jack, a Grove port for sensors, buttons, and LEDs, and two RS-232 serial ports.

Each connection serves a different job:

• Audio output: Stream music to an older amplifier, soundbar, or powered speaker through the audio jack, turning it into a networked speaker for whole-home audio.
• Serial control: Two RS-232 ports send commands to older AV receivers, TVs, and other equipment that still speaks serial, including Modbus devices with an inexpensive USB adapter.
• Bluetooth proxy: Extend Bluetooth coverage so Home Assistant can reach sensors and devices in rooms far from the main hub.
• USB radio hosting: Plug in a Connect ZWA-2 Z-Wave stick or a Connect ZBT-2 Zigbee stick and place it wherever it gets the best coverage, instead of tethering it to the server running Home Assistant.
• Grove port: Attach peripherals such as sensors, buttons, and LEDs for custom projects.

The device runs on ESPHome, the open platform for building smart home devices, and uses existing Home Assistant and ESPHome integrations for its features. Setup requires Home Assistant 2026.9 or later; the Zigbee option needs Home Assistant 2026.11.

Whole-home audio for the stereo you already own

The headline use case is audio. Many households have a good amplifier or soundbar that sounds great but cannot receive music from a phone or a multi-room system. The AUX-2 gives that equipment a network audio input: it streams lossless audio to the connected amp or speaker, powered by Music Assistant and the Sendspin player.

Early hands-on coverage shows the appeal in practice. Reviewer Rosemary Orchard connected the AUX-2 to an older Bose soundbar and had it playing in sync with her HomePods, while the same box doubled as a Bluetooth proxy and a new home for her Z-Wave stick. It is the kind of consolidation the device is built for: one small box replacing several single-purpose adapters.

There are limits worth knowing before buying. The AUX-2 has no audio input, so it cannot digitize a turntable or another analog source. It cannot send or receive Bluetooth audio, and it contains no speaker amplifier of its own. It is an output for your existing stereo, not a speaker in itself. No audio, serial, or power cable is included in the box.

Serial control that outlives the cloud

The two RS-232 ports may be the most interesting feature for long-term smart home owners. Serial is a two-way connection over a single cable, and it is still found on plenty of older amplifiers, receivers, and TVs. Because serial control does not rely on the cloud, it keeps working after a service shuts down, and your data stays in your home.

“Serial control doesn’t rely on the cloud, so it keeps working after a service shuts down and your data stays in your home,” said Paulus Schoutsen, founder of Home Assistant, at the launch. That local-first philosophy runs through the whole product: the AUX-2 is designed to keep useful equipment in service rather than pushing owners toward replacements.

The serial integration was developed earlier this year, while the audio software built on Music Assistant and Sendspin is still in active development. That is worth keeping in mind: this is a launch-day product whose software will keep maturing, and no independent long-term testing exists yet.

What it is not

As important as what the AUX-2 does is what it does not do. It contains no Z-Wave, Zigbee, or Thread radio of its own; it only hosts external sticks over USB. Zigbee support through the ZBT-2 is still officially in testing, and Thread connectivity is not supported and not planned for this product, according to Nabu Casa.

That makes the AUX-2 a complement to, not a replacement for, a dedicated hub such as the Home Assistant Connect ZBT-2 or ZWA-2. It is also useless without a Home Assistant setup: there is no standalone app or cloud service to run it.

Open hardware, repairable by design

In keeping with the open-source ethos of Home Assistant, Nabu Casa says it will release the AUX-2’s circuit board files and 3D-print files, letting owners repair, modify, or rehouse the device. It is a small but meaningful gesture against planned obsolescence, and it fits the product’s pitch: keep good hardware working instead of throwing it away.

Price, availability, and the bigger picture

The Home Assistant Connect AUX-2 is available now for $69 in the US and €59 in Europe, excluding tax in the US, with retailer prices and stock varying by region. It requires Home Assistant 2026.9 or later to set up and manage.

The launch comes as Home Assistant continues to grow beyond its hobbyist roots. Nabu Casa, the commercial side of the Open Home Foundation that runs Home Assistant, recently renamed Home Assistant Cloud to Link and has a successor to its Green hub in the works. The AUX-2 slots neatly into that strategy: affordable, open hardware that lowers the barrier to a local-first smart home.

For anyone with a shelf of older audio gear, a serial-controlled TV, or Bluetooth devices just out of reach, the AUX-2 is an unusually practical $69 purchase. It will not replace a hub, and it will not make a dumb speaker smart on its own. But as a bridge between the equipment you already own and the smart home you want, it is one of the most useful gadgets Nabu Casa has shipped.