Nabu Casa, the company that builds official Home Assistant hardware, has released the Home Assistant Connect AUX-2, a $69 box meant to drag old stereos, TVs and solar inverters into a modern smart home. The company calls it “a smart home multi-tool,” and the spec sheet backs that up: audio output, two serial control ports, a USB port, a sensor connector, a Bluetooth hub and Power over Ethernet in one small case.
It went on sale worldwide on November 11 for $69 in the US and €59 in Europe. Nabu Casa, formed in 2018 to run the paid Home Assistant Cloud service, has since built a line of official hubs and radio adapters, from Home Assistant Blue in 2020 to Home Assistant Green in 2023.
What the ports actually do
- Audio: a combined analog and optical digital jack. The box detects which cable is plugged in and switches output on its own, so a vintage amplifier can play a lossless music library.
- Two RS-232 serial ports: the decades-old control socket on the back of many receivers, TVs, projectors and inverters. Through it, Home Assistant can change volume, input and power, even waking gear from standby.
- USB-A: lets a Connect ZWA-2 Z-Wave adapter sit anywhere on the network instead of being stuck next to the server. A cheap RS-485 adapter on the same port opens the door to Modbus equipment.
- Grove connector: plug-in temperature, humidity or light sensors without opening the case.
- Bluetooth proxy: a tuned antenna that discovers Bluetooth devices as soon as the box joins Home Assistant.
- Power: USB-C or Power over Ethernet, which means one network cable can carry both data and power.
The name is a small joke. Nabu Casa product manager Shay Redmond explained in the launch post that AUX stands for Audio, USB and “X for serial,” adding that “it also sounds cool.”
The pitch: keep the gear you own
Most smart home launches ask buyers to replace something. This one argues the opposite. Redmond wrote that “the most sustainable device is the one you already own,” and the company frames AUX-2 as a way to rescue equipment from landfill or from a maker’s shaky cloud app.
The clearest example is the living-room TV. Nabu Casa suggests cutting a smart TV off the internet entirely and controlling it over serial instead, so the set keeps working while its tracking features lose their connection. Old hi-fi gets similar treatment: with Music Assistant and its new Sendspin protocol, an AUX-2 hooked to a 1990s amplifier can play in sync with HomePods or Sonos speakers in other rooms.
The trend fits a wider push toward local control. Earlier today we reported on a developer who tricked a Coway smart air purifier into talking to his Raspberry Pi instead of Coway’s cloud, a hack that took custom work. AUX-2 aims to make that kind of escape a plug-in job for any device with a serial port.
What it costs to run, and what it cannot do
Nabu Casa says the box never draws more than a watt or two. At 2 watts around the clock, that works out to about 17.5 kilowatt-hours a year, or roughly $3 at a typical US rate of 17 cents per kilowatt-hour.
There are limits. Thread devices do not work through it, because the protocol is too sensitive to network delay. Zigbee adapters do work, but Nabu Casa is not advertising that yet and wants more testers first. Some devices also need serial control switched on in their own menus before Home Assistant can see them.
The hardware is open to tinkerers: four Phillips screws, no glue, and firmware owners can replace. Nabu Casa says it will publish the circuit board and 3D-print files so modders can build their own versions. More gadget coverage is on our Tech page.
Further reading
Image: david falkner, CC BY 2.0 via Wikimedia Commons
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