lego-blockly

A Blockly environment in the browser that drives LEGO interfaces from Interface A to LPF2. JavaScript with a little C++, installable as an app.

VLL support

It explicitly supports "Virtual Light Link (Code Pilot, MicroScout)" alongside Interface A/B, RCX/ControlMaster, WeDo, and LPF2.

VLL implementation (device/DeviceLegoVLL.js)

• Emitter = an LED on a serial control line via Web Serial → lego-blockly.
• sendVLL(data7): preamble 1000 ms, start, 3 checksum bits + 7 data bits MSB-first, stop (ON 1u / OFF 3u). unit = 20 ms.
• VLL checksum = 7-((n+(n>>2)+(n>>4))&7) — identical to the one used by Flash Force.
• Opcodes are entered by the user (no built-in table); blocks: vll_senddata, vll_preamblems, vll_unitms.

Send VLL to a Micro Scout (quick start)

1. Open the live editor in Chrome/Edge (needs Web Serial). Wire a genuine FT232R/FT232H + red LED on the DTR pin — see lego-blockly.
2. Pick the VLL (Code Pilot/MicroScout) device and Connect (Web Serial picker).
3. Drop a vll_senddata block with a code from the VLL opcode table (e.g. 0 forward, 4–8 beeps, 33 Run, 34 Delete); tune vll_preamblems / vll_unitms if needed.
4. Run — Highlight Execution shows the active block, Log shows what was sent.

Build a stored program = Delete (34) → script steps 16–32 → Run (33), same flow as Flash Force.

Other devices

Serial via USB-RS232 / HC-05 BT / BLE / WebSocket. SketchArduino/ is Interface A firmware.

Significance

A second implementation of the VLL frame, written from another codebase, and an emitter that is one diode on a serial control line.

Links

• Live editor (try it in the browser): blissca.github.io/lego-blockly
• github.com/BlissCA/lego-blockly

How it drives the light

The browser side is one call: Web Serial's port.setSignals({dataTerminalReady}) drives a serial control line high and low, and a diode on that line is the whole emitter. Edges are timed by busy-waiting on performance.now() rather than by setTimeout, which is why its 20 ms unit holds.

The same job can be done from Python instead of a browser, with vllftdi.py from JorgePe/mindstorms-vll. One trap: pass auto_detach=False, or it segfaults.