Pybricks Hub Tester

Browser dashboard for Pybricks hubs. It connects over Web Bluetooth, scans hub ports, shows connected LEGO Powered Up / SPIKE devices, streams live values, and includes a motor DC sweep test.

Features

• Web Bluetooth connection to Pybricks firmware hubs.
• Hub model, firmware, profile, battery, voltage, current, and IMU readouts.
• Port dashboard for 2, 4, and 6 port hubs.
• Device detection for known Powered Up / SPIKE motors and sensors.
• Live values for motors, force sensor, ultrasonic sensor, color sensor, and color distance sensor.
• Per-port value mode selector, including angle, speed, force, pressed, distance, reflection, ambient, HSV, RGB, and color where supported.
• Motor Test tab with DC step selection, DC to RPM chart, DC to hub-current chart, startup duty, max RPM, peak acceleration, backlash, progress bar, and PNG export.
• Local BLE diagnostic script for debugging Pybricks GATT, REPL, PortView, and port scan behavior outside the browser.

Compatibility

• Requires a hub running Pybricks firmware.
• Requires a browser with Web Bluetooth support, usually Chrome or Edge.
• Requires a secure context. localhost works for local development, GitHub Pages works over HTTPS.
• Port scanning and live values use the Pybricks REPL and interrupt the current hub program.
• Live dashboard keeps a monitor program running on the hub while connected.
• Motor Test drives the selected motor through positive and negative duty cycles. Use it only when the mechanism can move safely.

Run Locally

npm start

Open:

http://localhost:4173

GitHub Pages

The app is static and can run from GitHub Pages:

https://aztechell.github.io/pybricks-hub-tester/

If the page looks mixed after an update, hard refresh the browser tab. The app also uses static asset version query strings to reduce stale-cache issues.

Test

npm test
node --check src\main.js
node --check src\pybricks.js
node --check src\parser.js

BLE Diagnostics

The browser UI is the main app. For lower-level debugging, use the Python diagnostic script:

python scripts\diagnose_hub.py --verbose
python scripts\diagnose_hub.py --port-view --verbose

Diagnostic traces are written to diagnostics/, which is ignored by Git.

Notes

• Battery percent is estimated from available hub battery data and voltage curves when the standard battery service does not provide a direct percent.
• Current shown in the dashboard is hub battery current. Motor Test current chart uses hub current delta, not a separate inline motor current sensor.
• Ambient light mode on color sensors is read only when selected, because it changes the sensor illumination behavior.