LED Scroller

Simulates a classic red LED scrolling marquee in the browser. Type up to 20 uppercase characters, pick a speed from 1 to 10, and start a self-running animation that scrolls the text through a 20-character window on a red LED-style panel.

1. Enter your message (auto-converted to uppercase, max 20 chars). 2. Drag the Speed slider (1 = slow, 10 = fast). 3. Click Start to begin scrolling; click Stop (red) to pause. 4. Click Reset to halt and show the raw text statically. 5. Click Copy to copy the currently displayed frame to the clipboard.

A timer advances one character position per tick, with the tick interval equal to 1000 / speed milliseconds. Each frame renders 20 characters drawn cyclically from the input plus 5 trailing spaces for continuous wraparound. On Stop the timer is cleared; on unmount any running timer is cleaned up automatically.