Hotaru - Live Penlight

Live penlight on your wrist

Free

Virtual penlight for concerts, festivals, and stadium cheering. Control it from your wrist — no ads, no signup, no data collection. Free forever. Hotaru is a virtual penlight app that lights up both your iPhone and Apple Watch — for concerts, festivals, sports games, and any moment that calls for cheering. Keep your phone in your pocket and change colors right from your wrist. Just rotate the Digital Crown to cycle through 16 colors. Even in the darkest venue, every control happens at your fingertip. 【 Features 】 ■ Apple Watch as the main control Raise your wrist and rotate the crown to switch colors. The Apple Watch screen itself glows in your chosen color, working as a small penlight on its own. Single-tap to light up, double-tap to turn off, long-press for an immediate blackout. ■ 16 curated colors Snow, Crimson, Coral, Tangerine, and more — 16 refined colors that shine at the venue, cycling smoothly with the crown. ■ Show your message inside the penlight Display the name of your favorite, a heartfelt message, or any text you love — right inside the penlight. Short messages appear large and centered; longer messages scroll smoothly like an LED message board. Mix Latin letters, kanji, hiragana, katakana, and emoji in any combination. Beautiful LINE Seed JP Bold typography. Tap any of your 8 most recent entries to reuse them instantly. ■ Vertical / Horizontal text (v1.4 new) Toggle between Japanese-style vertical writing and Western-style horizontal layout right from the input sheet. Match the style to your show — a traditional Japanese live atmosphere or a clean, social-media-ready look. ■ Landscape LED ticker mode (v1.4 new) Set your phone down sideways and the penlight transforms into a horizontal LED ticker. Perfect for stadiums, festivals, and marathon cheering — anywhere you want your message to be seen from a distance. 【 Beyond concerts — sports & cheering 】 Hotaru is not just for live music. The 16-color palette and LED ticker mode shine just as bright at: · Baseball stadiums — pick your team's color and rally with chants · Soccer / football matches — display your player's name or number · Marathons — cheer your runner with their name from the roadside · Festivals & school events — light up the crowd in your team's color Whatever you want to cheer for, Hotaru turns your phone into a personal cheering tool. ■ Brightness lock In fullscreen mode, the app overrides iOS auto-brightness and locks at a fixed value. Match the brightness of other penlights in the venue. Adjust the maximum from the Settings tab. ■ Dark UI Bright white screens can be distracting in a venue. Switch to Dark in Settings and the entire UI goes low-light, while the glow color in fullscreen mode stays unaffected. ■ Built-for-the-dark haptics Every action provides tactile feedback so you never need to look down. ■ Safety reminders A drop-prevention modal appears on first launch, and a wrist-strap reminder pops up before entering fullscreen mode. 【 Privacy 】 · No ads · No signup (no email, no social login) · All data stays on your device · Zero third-party SDKs, zero analytics 【 Before you use 】 Please check your venue's smartphone usage rules before use. Always attach a wrist strap (or similar drop-prevention accessory) and slip it onto your wrist before swinging. The developer assumes no responsibility for any accidents or damages resulting from the use of this app. 【 About 】 KARABINA LLC (Tokyo, Japan) A small studio building utilities for live show fans.

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v1.6 update 【 Improvements 】 ■ Scroll / Fixed toggle for the ticker Horizontal mode now has a Scroll / Fixed toggle. Let a short name flow across the screen, or hold a longer message in place — your choice, regardless of length. ■ Smoother scrolling Fixed an issue where scrolling text could visibly jump at the seam. It now loops seamlessly from edge to edge. ■ Other Minor display polish and stability improvements. Thank you for using Hotaru, and have a great show!

Version 1.6

The developer, KARABINA, LLC, indicated that the app’s privacy practices may include handling of data as described below. For more information, see the developer’s privacy policy .

  • Data Not Collected

    The developer does not collect any data from this app.

    Privacy practices may vary based, for example, on the features you use or your age. Learn More

    Accessibility

    The developer has not yet indicated which accessibility features this app supports. Learn More

    Information

    Provider
    • KARABINA, LLC
    Size
    • 8.2 MB
    Category
    • Entertainment
    Compatibility
    Requires iOS 17.0 or later.
    • iPhone
      Requires iOS 17.0 or later.
    • Apple Watch
      Requires watchOS 10.0 or later.
    Languages
    • English and Japanese
    Age Rating
    4+
    Copyright
    • © 2026 KARABINA LLC.
  • Developer Website
  • Privacy Policy

    • More by KARABINA, LLC

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