Works with stock LEGO firmware over BLE. Uses the Pybricks BLE UART service when Pybricks firmware is installed. Chrome/Edge on any OS, Android Chrome, or the desktop app.
1Make sure the hub is on and Bluetooth is enabled on your device.
2Click Connect via Bluetooth. A device picker opens — select your hub (named Technic Hub, LEGO Hub, or similar).
3Hub running Pybricks firmware: full REPL available. Hub running stock LEGO firmware: limited (beep/status only — use Download .lms for full programs).
🔌 USB Hub Connection (Web Serial)
Requires Pybricks firmware on the hub. Stock LEGO firmware exposes a HID device, not a serial port — use Bluetooth or download .lms files instead.
2Click Connect Hub via USB. Pick the port — usually USB Serial Device (COMx) on Windows or /dev/ttyACM0 on Linux.
3If the port picker is empty, try Show all ports or install the LEGO MINDSTORMS app to register the COM driver.
Hub Terminal
Send raw commands to the hub REPL (BLE or USB, Pybricks firmware required). Try: hub.speaker.beep()
Open .lms Files
Inspect any .lms file (Python or Blocks) saved from the LEGO MINDSTORMS app or downloaded from this tool.
🔌 RCX IR Tower (Serial / USB‑to‑Serial)
Connect the original LEGO RCX 1.x/2.0 brick via the serial IR tower and a USB-to-serial adapter (Prolific PL2303, FTDI, etc.). Requires Chrome or Edge with Web Serial API enabled.
1Install adapter driver. Plug adapter + IR tower into USB. Windows: check Device Manager for the COM port number.
2Turn the RCX on. The LCD should show a running timer. Aim the tower at the RCX’s IR window (front of brick, ~30 cm or less).
3Click Connect RCX and select the COM port from the browser picker.
4Click Ping to verify two-way IR communication, then use the motor controls below.
Motor A
Motor B
Motor C
To upload compiled programs: generate NQC code in the Code tab, then use BricxCC or nqc CLI. Direct program upload via Web Serial is in progress.
Edge Impulse Keyword Spotting
Load your Edge Impulse KWS model (WebAssembly deployment) to control the robot with voice commands. Train a model at edgeimpulse.com with keywords like forward, stop, left, right, wave, then export as WebAssembly → Standalone.
1In Edge Impulse: go to Deployment → WebAssembly → Standalone and download the ZIP.
2Extract the ZIP and pick the edge-impulse-standalone.js file below.
3Click Load Model, then Start Listening. Allow microphone access when prompted.
4Speak a keyword — detected words above the confidence threshold will trigger robot actions via USB REPL.
— or —
Keyword → Action Mapping
Map each model label to a robot action. Actions run as REPL commands on the connected hub (requires Pybricks) or as server code-gen + download.
