Traffic Lights

Recommended before this lesson:

Your objective

Run at least two cycles: red LED 1 for at least 2 seconds → green LED 2 for at least 2 seconds → yellow LED 3 for at least 1 second. Only one light may be ON, including between waits.
Read the timestamped trace and exported code. Explain which state changed, how long it lasted, and why the input caused that response. Change your blocks and run again; Stop cancels, Reset keeps your blocks. Explanations are for reflection, not automatically graded.

Translations are draft and need educator review.

Drag blocks from the toolbox into the workspace. Connect statement blocks beneath Start. Use the zoom controls to see your program.

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My Projects

Run and follow this lesson’s rubric and hints. Completion requires observed behavior in one finished run.

Stop ends the current run and keeps the current device state. Reset clears the device and output, keeping blocks.

Virtual Traffic Lights

Three virtual signals with red, yellow and green LED illustrations. Teaching GPIO assumptions: 2 / 4 / 16; board compatibility unverified.

Red · LED 1: OFF

Yellow · LED 3: OFF

Green · LED 2: OFF

0 ms

Execution output

Read-only code preview

Connect one Start and all supported blocks with valid values to preview or run.

Editor keyboard and screen reader access has not been verified. The surrounding instructions and controls are keyboard accessible. Practical alternatives: run the preloaded starter program, import/export workspace JSON, or inspect the read-only JavaScript, MicroPython, and C++ code preview.