Helmet Decal Charger Keeps Them Ready To Glow

When firefighters are battling a blaze, it’s difficult for them to find each other in the smoky darkness. To help stand out they wear glow-in-the-dark decals on their helmets, but since they spend so much of their down time stowed away in a dark locker, they don’t always have a chance to charge up.

[Bin Sun]’s firefighter friend inspired them to build a portable charging system that can stuff those helmet decals full of photons in a matter of minutes. Although phosphorescent materials will charge in any light, they charge the fastest with ultraviolet light. This uses a pair of UV LED strips controlled by an off-the-shelf programmable timer, and powered with an 18-volt drill battery stepped down to 12 V. The timer makes it easy for [Bin Sun]’s friend to schedule charge times around their shifts, so the battery lasts as long as possible while keeping the decals ready to glow.

We love that [Bin Sun] seems to have thought of everything. The light strips are nestled into 3D-printed holders that also house small magnets. This makes it easy to position the lights on either side of the locker so both the front and back decals soak up the light.

Phosphorescent materials are great as a reusable display medium, especially when they’re designed to look like Nixie tubes.

9 thoughts on “Helmet Decal Charger Keeps Them Ready To Glow

    1. The light doesn’t need to be stronger than daylight, and it won’t be on all the time. Also, most commercial UV LEDs have a limited spectrum so they probably don’t cause much chemical damage.

  1. As a firefighter, this makes no sense whatsoever from a practical standpoint. If there are visibility concerns (smoke), a decal isn’t going to cut through the haze one bit. A good flashlight and knowing how to get around the smoke is what helps visibility until you get proper ventilation. A decal that glows won’t help. Might just be a cool gag, I dunno.

    1. The author was not very specific on this point, but uniforms, protective equipment, and even firefighting tools are often designed for high visibility to ensure that fire scenes are safe and that people are accounted for. There are, of course, many hazards at a scene other than the fire itself, and visibility is one way to mitigate these. Even the brightest luminescent materials would be hard to spot in an active fire, but may be helpful in making sure that people can be seen in poorly lit areas, and that no firefighter, tool, or helmet is accidentally overlooked or left behind.
      Regardless, seems like a nicely designed device and build, and LEDs seem like a must given the durability needs of the general fire house environment (at least in my experience).

    2. What about blinking/breathing LED waistband packs? You could even have them play a unique chirp pattern tone at intervals, when you press a button, or whenever *anyone* presses the “echo” button (With a wireless signal) so if you can’t find someone, you press echo on your own pack and listen for the reply?

      They could be also be integrated with accelerometers to alarm in case anyone stops moving for X seconds too.

  2. These glow-in-dark materials usualy stopped working pretty soon for me. Becoming really faint in year or so. Is there something specific that i can do to prevent them from aging? Eg. not exposing them to the light when not in use? When i blast aged one with UV, it kinda glows, but stops in few seconds. I guess there is no real way to revive them. And yes, you can use tritium if you want something to keep glowing for long time. But that’s not really suitable for toys and stickers.

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