Plug the board in
Use a real USB-C data cable — charge-only cables won't show up as a serial port. If it's your first flash, hold the BOOT button while plugging in.
Click Flash
Chrome, Edge, or Opera on desktop. Your browser will show a list of serial ports — pick the XIAO. The install takes about 30 seconds and wipes the board clean before installing.
Listen for the boot jingle
The board reboots on its own and plays four ascending beeps — it's awake and already scanning for Axon gear. That's the whole setup. There is deliberately no Wi-Fi to join and no portal to open.
- Wi-Fi
- none
- Portal
- none
- Interface
- beeps only
4 ascending beeps
G4 → C5 → E5 → G5. Power on, jingle, scanning. Armed in about a second and a half, no buttons, no config.
8-bit ascending arpeggio
An Axon device was just heard — body cam, Taser 7/10, Signal sidearm, Fleet. Seven signatures across BLE and WiFi: company ID 0x034D, service UUIDs 0xFC81 / 0xFE6B / 0xFE6C, IEEE OUI 00:25:DF on both radios.
Lub-dub, rate = proximity
While the target stays in range a two-beep heartbeat keeps time — about every 2 seconds when it's far or weak, down to every 250 ms when it's close and strong. Walk it down like a foxhunt.
Descending 2-beep
8 seconds of silence and the target is gone — one falling pair of beeps, then AXEOFF goes back to idle and the next fresh hit re-triggers the arpeggio.
All passive, all the time
AXEOFF never transmits: passive BLE scan (no SCAN_REQ) plus promiscuous listen-only WiFi, with a randomized MAC on every boot. It hears everything, says nothing.
Nothing shows up in the port picker
Try a different USB-C cable (charge-only won't work), or hold BOOT while plugging in to force download mode.
Flashed but completely silent
AXEOFF needs a buzzer on GPIO3 (D2) — a bare XIAO ESP32-S3 doesn't have one onboard, and it must be a passive buzzer (active ones just wail). The OUI-SPY board already has it integrated.
I want to see what's happening
Serial at 115200 baud prints one JSON line per detection — MAC, RSSI, signature, human note. pio device monitor -b 115200, or any serial terminal.
Where's the web portal?
There isn't one — that's the point. No AP, no config page, no MQTT. Power, buzzer, ears. If you want the full dashboard experience, run OUI-SPY Unified — AXEOFF is also Mode 7 there.