Scrolling LED Sign Maker for Concerts

What is a scrolling LED sign maker?

A free tool that turns whatever text you type into a full-screen scrolling display, like the running-text signs used for cheer boards, arrival pickups and shop counters. It runs entirely in your browser, so nothing you type is uploaded anywhere.

Can I make one without installing an app?

Yes — that is the whole point of this being a web page rather than an app. Open it, type your text, pick a color and mode, and press fullscreen. There is nothing to download and no account to create, and the text never leaves your device.

How do I use it?

1. Type the text you want to display
2. Pick a text color and background color, from the presets or a color picker
3. Choose a display mode (scroll, bounce, blink or static), a speed and a font size
4. Toggle Dot matrix for the LED grain, Vertical to stack the text downwards, and Orientation to rotate the sign
5. Press Show fullscreen to fill the screen with your banner

Turning your phone sideways lets each line of text render larger and easier to read at a distance. If rotation lock is on and the screen stays portrait, press Orientation to turn the sign itself instead.

Copy link with these settings puts the text, colors, mode, speed, font size, vertical setting and orientation into a URL. Whoever opens it starts from the same sign you built.

In fullscreen the close button fades out after a few seconds so the display is just text. Tap anywhere on the screen to bring the controls back before pressing close.

Which of the four display modes should I use?

It depends on the length of the message and how much attention it needs to grab. Long lines suit scroll, short words suit bounce, blink is for a split-second attention grab, and static is for holding a message in place.

When in doubt, scroll works for almost anything — there is no character limit, and even a long line eventually reads end to end. Blink is the exception: it costs attention from anyone nearby, so keep it brief. For an arrivals pickup where someone is scanning a crowd for a name, static is usually easier to spot than a moving line.

Can it look like a real dot-matrix LED board?

Yes — the Dot matrix toggle lays a grid mask over the text so the letters read as a field of lit dots, the way a real LED board does. It is on by default.

Dot spacing follows the font size, sized so a character's height splits into roughly 18 dots. Coarser than that and the thin strokes in kanji and kana break apart between dots; finer and the grain disappears into plain text. A 60px font gives 3px spacing, and the 300px maximum gives 17px. It never drops below 3px however small the text gets.

The difference shows up most in photos. With the mask off you have large plain text; with it on the grain reads as a sign. For maximum legibility at a distance, turn it off — the letter edges stay sharper without the grid.

How is the loop time calculated?

One full loop takes (screen width + estimated text width) ÷ speed seconds. Text width is estimated at the font size for wide (CJK) characters and 0.55 times the font size for narrow (Latin) characters — which covers ordinary English text.

For example, at a 60px font size, the seven-character word "WELCOME" comes out to roughly 231px wide. On a 375px-wide phone screen at 120px/sec, the full loop distance is 375 + 231 = 606px, so it takes about 5.0 seconds to loop once. Longer text or a slower speed both stretch that out.

With the same assumptions (screen width 375px, font size 60px), here is how loop time changes with message length and speed:

Speed ranges from 10 to 400px/sec, so the three columns above are only a slice of what is available. Go slower if you want people to stop and read it, faster if it just needs to catch a passing eye.

Why does the blink mode have a speed limit?

To keep it clear of the photosensitive-seizure threshold. The shortest interval you can set is 250ms, and the tool will not go faster than that.

Blink alternates on and off once per cycle, so the flash rate in Hz works out to 1000 ÷ (2 × interval in ms). At the fastest setting that is 1000 ÷ (2 × 250) = 2.0Hz — comfortably under the 3Hz limit the WCAG photosensitive-epilepsy guideline sets as a safety threshold.

Why does my screen keep dimming while I'm holding it up?

Pressing Show fullscreen asks the browser to keep the screen awake using the Screen Wake Lock API. Most desktop and Android browsers support it, but iOS Safari only gained support in version 16.4 — on an older iPhone, or in a browser that otherwise blocks it, the display will still time out on its own.

If your device isn't covered, tap the screen occasionally while it's up to reset the sleep timer.

Can the text run down the screen instead?

Yes — Vertical stacks the characters one per line, top to bottom, so you can hold the phone upright and nobody has to tilt their head to read it.

This is how Japanese signage usually runs, and it is the better setting for holding up a name at an arrivals gate. Character size is the same either way: the screen's short edge caps it whether the text runs across or down. What changes is how you hold the phone and whether the reader tilts.

Each character gets one cell, so the spacing stays even however Latin, kana and kanji are mixed. Long vowel marks and Japanese brackets are laid on their side to match vertical typesetting; commas and full stops sit centred in the cell rather than in the upper-right corner, because a real LED board places everything on a fixed grid.

Latin letters stack upright, the way vertical shop signs and banners set them. Word boundaries get harder to pick out that way, so for English the horizontal default usually reads better.

Can I hold it sideways with rotation lock on?

Yes — Orientation turns the sign itself 90° at a time, so you get a landscape banner without unlocking rotation in your device settings.

With rotation lock on, tipping the phone sideways leaves the screen in portrait, and clearing it means going back to settings or the control centre. Turning the sign instead skips that. The button steps through 0°, 90°, 180° and 270°, so stop at whichever matches how you're holding the phone — 180° is for holding it upside down to keep a charging cable out of the way.

Rotating a portrait screen to landscape makes the sign's long edge horizontal, which lengthens the distance the text travels and stretches the loop time to match. If the same message feels slower after rotating, nudge the speed up.

This is a different job from Vertical: vertical is for reading the sign with the phone held upright, orientation is for holding the phone on its side. You can use both together.

What color combination is easiest to read from a distance?

High-saturation text on a black background reads best — the same setup real LED signs use. The bigger the difference in lightness between text and background, the more the letters hold their shape from far away.

For a night show, pick a black background — the darker the room, the more the text alone seems to glow. Outdoors in daylight, that contrast washes out, so switch to static mode and a larger font instead; motion only makes low-contrast text harder to catch.

Avoid pairs with similar lightness, such as gray on white or navy on purple — readable up close, blurred at a few meters. Push one color toward pure black or pure white if you're unsure; black background is the safer default.

Tips for using it as a fan sign at a concert

Keep the message to 6–8 characters. That keeps each loop short enough to read in a single glance, which matters more than it sounds — the table above shows how much loop time grows once a line passes a dozen characters. Pick either a name or a short phrase, not both; cramming both in means the line scrolls off before anyone finishes reading it.

• Holding up a name? Use Vertical — the phone stays upright and nobody tilts their head
• For horizontal text, hold the phone landscape; if rotation is locked, use the Orientation button instead
• Turn the screen brightness all the way up and disable auto-brightness
• Fullscreen mode drains the battery faster (it's keeping the screen from sleeping); bring a power bank for a long show
• Blink mode is visible to everyone nearby, not just you — keep it short

Concert etiquette to keep in mind

Hold the sign at chest height rather than overhead — the same courtesy that applies to a paper sign applies here, and a lit phone screen is if anything more noticeable in a dark venue. Lower or turn it off during quiet moments between songs or when the artist is speaking.

Many venues and tours publish rules on light sticks, signs and phone use, and some restrict them outright — check before the show, since being asked to leave is worse than not bringing one.

Keeping the display from being interrupted mid-show

Turn on airplane mode or a do-not-disturb focus before you start. The most common interruption is a notification banner or an incoming call sliding over the display right when someone looks up.

Turn off low-power mode too — it dims the screen and shortens the auto-lock timer, both of which can cut a display short. A power bank plugged in during use is more reliable than relying on low-power mode to stretch the battery.

Notes

• Some venues restrict light sticks or lit phone screens — check the rules before you go
• Blink mode carries a photosensitive-seizure risk; skip it if you or someone nearby has a seizure disorder
• Nothing you type is saved, on the device or on a server — reloading resets everything to the defaults. To keep a sign, copy the link with its settings
• On devices without the Fullscreen API, the display fills the screen using a simplified fullscreen view instead

Need something else to make and share? The custom emoji generator turns text into a transparent-background PNG for Slack and Teams — also free, also entirely in your browser.