A "Hey Keryx" voice speaker for the Hermes agent. A XIAO ESP32S3 on a Seeed reSpeaker Flex XVF3800 listens for its wake word on the device, then lets you talk to Hermes out loud: your request goes over Wi-Fi to a small voice bridge next to Hermes, and the answer comes back as speech. A sibling of RaspiDR on different hardware.
Keryx (κῆρυξ) is Greek for a herald — the one who speaks aloud for Hermes.
The first Keryx, built into an Edifier R1100 speaker (how):
| Front | Back | Demo (download) |
|---|---|---|
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demo.mp4 |
🔧 How it was built: the wiring, the parts and photos of the assembly.
- Wake word on the board. "Hey Keryx" (or «Хей / Эй, Керикс») is recognized by a small streaming model trained for this project and running on the ESP32-S3; nothing leaves the room until it is said.
- Talk, not commands. After the wake word the conversation goes on without it: ask a follow-up, or talk over an answer to stop it. A few seconds of silence end the conversation.
- Hermes does the thinking. Requests go to Hermes through its OpenAI-compatible API, with all its tools, memory and skills; the answers are short and written for the ear.
- Hermes can speak first. The bridge gives Hermes
say.shfor reminders, timers and anything you asked to be told later, andset_volume.shfor the speaker's volume. - The room stays clean. The XVF3800 cancels Keryx's own voice from the microphones (its playback is the echo reference), beam-forms towards the speaker and suppresses noise; the bridge filters what echo is left.
From the end of a sentence to the first sound takes about a second plus Hermes' own thinking time. Speech costs roughly $0.004 per exchange with xAI (why xAI).
- A reSpeaker Flex XVF3800 with a XIAO ESP32S3 and its U.FL Wi-Fi antenna, and a speaker on its 3.5 mm output (or a 4 Ω speaker on its JST amplifier output, which needs the 12 V input).
- Hermes with its API server enabled.
- An xAI API key for speech-to-text and text-to-speech.
- A Linux machine on the same network for the bridge — usually the one running Hermes. Python 3.10+, git-lfs.
On the machine that will run the bridge, with the board connected by USB:
git clone https://github.com/Flopsstuff/keryx.git && cd keryx
./setup.shsetup.sh installs the bridge as a service, asks for the keys, flashes the board and pairs it with the bridge over
Wi-Fi; after that the board runs on any USB power supply. The XVF3800 itself needs Seeed's I2S firmware once,
before anything else — see flashing.
docs/index.md is the map: flashing and pairing, the bridge, building the firmware, training the wake word, the board's hardware notes and the measurements behind the design choices.
Apache License 2.0. Vendored components keep their own licenses: firmware/components/micro_frontend
(TensorFlow Lite Micro's frontend, Apache-2.0, with KISS FFT, BSD-3-Clause) and
firmware/components/usb_device_uac (Espressif, Apache-2.0).
Work in progress.