ZeroTrace BLELogger
Installation & Setup
Flash firmware, plug the keyboard, pair the BLE host
Three phases: flash (one-time), plug (USB keyboard in), pair (BLE host).
What you need
- ZeroTrace BLELogger (ships pre-flashed)
- USB-C data cable for the COM port
- USB keyboard you want to bridge
- BLE-capable host (phone, tablet, laptop)
- Chrome or Edge for firmware updates
1. Flash firmware (only if needed)
Pre-flashed devices skip this. Flash for updates or recovery.
- Connect the device's COM port to your computer with a USB-C data cable.
- Open the ZeroTrace Web Flasher in Chrome or Edge.
- Click Connect, pick the serial port, Flash Firmware.
- Wait ~2 minutes. Don't unplug.
- Re-power.
Linux serial permissions. If the browser shows Failed to execute 'open' on 'SerialPort':
# Debian / Ubuntu / Pop / Mint
sudo usermod -a -G dialout $USER
# Arch / Manjaro
sudo usermod -a -G uucp $USER
Log out and back in.
2. Port roles
| Port | Plug into |
|---|---|
| COM (USB-C) | Computer for firmware/config; or any 5 V power source. |
| USB (USB-A) | The keyboard you want to bridge. |
Wrong port: nothing breaks but nothing works.
3. Plug the keyboard
- Connect a USB keyboard into the BLELogger's USB-A port.
- Power BLELogger via the COM port (any USB charger, laptop, or power bank).
- The device reads the keyboard's USB descriptors within ~1 s and starts auto-spoofing the BLE identity to match.
The keyboard is now active — keystrokes are buffered and forwarded as soon as a host pairs.
4. Pair the BLE host
- On your phone/tablet/laptop, open Bluetooth settings.
- Search for a device with the keyboard's name (e.g.
Logitech K120). - Pair. No PIN required for standard HID profiles.
- Type on the USB keyboard — keystrokes appear on the host.
First-pair character mismatch? Run keyboard calibration in the web UI before logging or substitution rules will be wrong. See section 6.
5. Web UI access
Default AP credentials:
| Setting | Value |
|---|---|
| SSID | [DeviceName] ZT |
| Password | ZeroTrace |
| URL | http://192.168.4.1 |
Connect to the AP, open the URL — see Web UI.
6. Calibrate the keyboard
The web UI's Calibration panel walks you through a one-time per-keyboard handshake — you press a guided sequence of keys, BLELogger maps physical scancodes to layout characters, calibration profile saves to flash.
Without calibration, BLELogger sees raw scancodes and can't reconstruct typed text accurately for keylogging or regex matching. Bridging still works for typing — only the inline-log side needs calibration.
Troubleshooting
| Symptom | Fix |
|---|---|
| Keyboard not detected | Try another USB keyboard or a known-good cable. Some gaming keyboards expose multiple HID interfaces — BLELogger pairs to the first one. |
| BLE not pairing | Restart BLELogger and the host's Bluetooth radio. Forget any old pairing on the host. |
| Wrong characters logged | Run calibration. |
| Web UI unreachable | Confirm you joined the ... ZT SSID; try a different browser. |
| Flashing fails | Use a stable USB data cable directly into the host (no hub). |