Nabu Casa shipped the Home Assistant Connect Aux-2 on November 11 for $69, introducing a card-sized hardware hub designed to pull non-smart electronics into home automation networks.
Hardware Architecture and Ports
The Connect Aux-2 runs on an Espressif ESP32-S3 microcontroller module paired with 8MB of pseudo-static RAM and 8MB of flash storage. The device includes a Texas Instruments PCM5122 audio chip and a WIZnet W5500 Ethernet controller, delivering single-band 2.4GHz Wi-Fi, Bluetooth 5 Low Energy, and wired Ethernet with Power-over-Ethernet support alongside USB Type-C power.
Physical connections span a USB Type-A port, a digital and analog audio jack, a Grove port for sensors, buttons, and LEDs, and two RS-232 serial ports. Users can add a $15 USB-to-RS485 adapter to communicate with Modbus devices, or plug in a ZWA-2 Z-Wave adapter to extend wireless coverage.
The box is built around ESPHome, letting users add it to Home Assistant like any other ESPHome device without needing a separate app or account. “set up your ESPHome device page” was the prompt given to users after installing ESPHome, which discovers the hardware and opens a configuration page explaining its capabilities, the reporter said.
Audio Synchronization and Local Control
The hardware pairs with Music Assistant to stream local files and services like Spotify and Tidal to older hi-fi amplifiers and receivers. Audio output relies on the Sendspin protocol for synchronized whole-home playback across different speaker brands, letting older legacy audio equipment play alongside compatible Sonos or Apple HomePod speakers.
Serial connections allow users to govern power, volume, and input selection on older AV receivers and televisions without relying on manufacturer cloud servers. Home Assistant notes that local TV control lets households disconnect smart displays from the internet to limit data collection.
The serial ports can also manage solar inverters and AV equipment directly through RS-232 cables, while the audio jack connects to powered speakers or external amplifiers to stream music to vintage gear.
The most sustainable device is the one you already own. No device should be left behind because it doesn’t have smart capabilities, or worst of all, its cloud services get turned off.
Paulus Schoutsen, founder of Home Assistant and Nabu Casa
Home Assistant Connect AUX-2 Costs $69 in the United States
Priced at $69 in the United States and €59 in Europe, the Home Assistant Connect AUX-2 arrives alongside alternative hardware options like Apollo Automations’ $35 Cast-1. Nabu Casa and Apollo both finance the Open Home Foundation, which governs Home Assistant, ESPHome, Music Assistant, and Sendspin.
“So bring back that great-sounding, but forgotten, hi-fi and have it play in sync with Sonos or AirPlay speakers. Take that solar inverter or TV with an annoying app and wire it into Home Assistant with a serial connection. Connect AUX-2 helps you take back control of the devices in your home, and because it's fully open, our community will keep finding amazing new uses for it,” Home Assistant founder Paulus Schoutsen said.
The device ships with an unlocked bootloader running ESPHome firmware, and Nabu Casa plans to release its circuit board design and 3D-print files for enthusiasts building custom integrations. The system handles multiple platform setups by mixing Google Home, Apple Home, and Home Assistant environments.
