Nabu Casa – the commercial arm of the Open Home Foundation, which runs Home Assistant – has just launched Home Assistant Connect Aux-2, a multifunction box designed to help you integrate more non-smart devices into your smart home. This is part of Home Assistant’s ongoing efforts to become more user-friendly. And it works.
I’ve been testing the Aux-2 for a few days and found it unsurprisingly useful and surprisingly easy to set up. The Aux-2 is a $69 box the size of a deck of cards. It features 2.4GHz Wi-Fi, Bluetooth, Ethernet, USB-A, USB-C, a digital/analog audio jack, a Grove port for interfacing with peripherals such as sensors, buttons and LEDs, and a pair of RS-232 serial ports.
It can link Bluetooth devices to your Home Assistant setup. Its USB port allows you to plug in a Nabu Casa Z-Wave or Zigbee antenna in case your Home Assistant hub isn’t in the right place. You can control devices such as TVs, AV receivers, solar inverters and more through a serial connector. And you can connect an amplifier or powered speakers to its audio jack to stream music to older audio equipment.
All of these things leverage Home Assistant’s capabilities as an open source platform. The Aux-2 is based on ESPHome, an open platform for making smart home devices from flexible, low-cost ESP boards, and uses existing Home Assistant/ESPHome integrations for all its functionality. Serial integration was developed earlier this year; Music Assistant and SendSpin, which power the audio output feature, are in active development.
I installed Home Assistant, but even after several years, it’s not my primary smart home platform simply due to friction and time constraints. Instead, I have a hodgepodge of Google Home, Apple Home, and a few devices only available in Home Assistant. The situation is not ideal.
But the Aux-2’s capabilities intersect nicely with two things I was planning to do anyway, for which I already use Home Assistant. First, I have a garage refrigerator, because I live in Texas. I also have children, so sometimes the refrigerator or freezer door is left open. I want to know when this will happen before all my food goes bad.
A few years ago, I installed a few Aqara temperature sensors, connected to Home Assistant via a now-discontinued Zigbee dongle, and set up an automation to alert me if the fridge or freezer gets too hot. But they drop the connection frequently (probably because they’re in a refrigerator in the garage), they chew button batteries, and they don’t have a screen, which means I also have a cheap Acu-rite hygrometer in the refrigerator so I can see the temperature without taking out my phone. Someone told me about Govee’s Bluetooth hygrometers, but I would need a Bluetooth proxy to integrate them with Home Assistant. This happens to be a feature of the Aux-2.
I also have a set of wall speakers in my living room that I’ve never used. I was planning on getting an amp, but analysis paralysis set in. Do I get a Wiim amp? A stereo receiver? A cheap Bluetooth amplifier? Should I try to make them work with my four Sonos speakers? Maybe my old Google Home speaker? It turns out I don’t do anything for five years. Maybe the Aux-2 could help.
Setting up the Aux-2 was much easier than expected. I plugged it into my computer via USB-C and was able to download and install the latest firmware directly from a browser. I could also add my Wi-Fi credentials. Then I unplugged it, moved it to my media console and connected it to power (requires USB-C or power over Ethernet), and did the rest of the setup in the Home Assistant interface.
In HA, I was prompted to install ESPHome, which discovered the Aux-2 and sent me to a “configuring your ESPHome device page” that guided me through the features. Enabling the Bluetooth proxy took a few clicks; I added the Govee Bluetooth integration and put batteries in the sensors and they showed up automatically. Luckily, they maintained their Bluetooth connection through three walls and a refrigerator, and now my refrigerator monitoring setup works again.
The audio capability took a little longer, but most of it was spent hooking up the speakers to the amp I ended up purchasing and setting up Music Assistant, which I didn’t have installed. Music Assistant lives on your Home Assistant hardware and can play from many different services – from Spotify to YouTube Music to local files and more – and has many different outputs, like Sonos, Wiim, AirPlay, Google Cast and others, but they all need to be set up, and that took a while. Not a long pace: less than half an hour in total.
I can now listen to music on the wall speakers using Music Assistant. Sendspin, the whole-home audio standard (also developed by the Open Home Foundation) is supposed to be able to let you group speakers of different protocols together under certain conditions, but I haven’t gotten that to work yet. The standard is still under development and I’ve also been busy, so I don’t know if this is an issue for me or them.
I’d also like to see the Aux-2 show up as an AirPlay or Spotify Connect target, which (again) is probably just something I need to configure.
Serial control is the most intriguing feature of the Aux-2, and it’s unfortunately the one thing I haven’t had time to test yet. But the ability to connect things like solar inverters, TVs and receivers is fascinating and one I want to explore further when I get the chance. Maybe I’ll connect it to my LG TV.
The Aux-2 doesn’t do anything that you can’t already do with an ESP32 board and various accessories, or even other ESP-based devices. The Apollo Automations Cast-1, for example, costs $35 and supports the same music streaming and Bluetooth proxy features I currently use from the Aux-2. You could create something even cheaper with DIY parts.
This is not a knock against the Aux-2. That’s all indicate. The ecosystem is open by design, which I find endlessly refreshing. Both Nabu Casa and Apollo fund the Open Home Foundation, which develops Home Assistant and ESPHome (as well as Sendspin and Music Assistant), and both provide hardware that’s a bit easier to use than DIY options. But nothing stops you from making your own devices. This is actively encouraged.
I bought a three-pack of ESP32 boards for $16 three years ago. I could have created a Bluetooth proxy from one of these. I could have built an LED controller. I could have built a floor sensor, a media player, or a dozen other things. I didn’t do anything at all.
But now that I’ve used the Aux-2 and dipped my toes into the ESPHome waters, maybe I will.
Gn tech
